Category Archives: High Altitude

Acclimation, Altitude Science, Health, High Altitude, High Altitude Training & Fitness, Mountaineering

Understanding the effects of nocturnal hypoxemia in healthy individuals at high altitude: A chance to further our understanding of the physiological effects on residents in Colorado’s mountain communities

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The population of Summit County, Colorado is projected to grow by 56% between 2010 and 2030. Along with adjacent Park and Lake Counties there are now over 40,000 people living above 2800 meters elevation. This is the largest high altitude population in North America. As opposed to native populations in South America, Africa and Asia who have been residing above 2800 m for centuries, the North American residents are acclimatized but not adapted. Symptoms related to hypobaric hypoxemia are notable above 2500 m.  Recognized conditions associated with altitude include central sleep apnea leading to hypoxemia (abnormally low oxygen level in the blood) which activates the sympathetic nervous system. In susceptible persons this can cause systemic and pulmonary hypertension. The incidence of this potentially devastating side effect of mountain living is unknown.  In order to better understand the potential side effects of nocturnal oxygen desaturation in healthy individuals, it is beneficial to investigate the normal physiological changes that occur during sleep, which leads to low oxygen levels in all individuals.

When the body enters the sleep state, many of the behavioral mechanisms that are active during wakefulness are blunted, and it’s been found that different sleep stages have varying effects as well.  One of the major changes is a diminished response to hypercapnia (high carbon dioxide levels in the blood) and hypoxia.  During sleep, the CO2 set point is elevated from 40 mmHg to 45 mmHg, which results in reduced alveolar ventilation.   It’s also observed that minute ventilation is reduced, which is due to decreased tidal volumes that is normally compensated for with an increase in breathing frequency during wakefulness.  Also, during sleep, there tends to be upper airway narrowing that is normal and there is reduced reflex muscle activation of the pharyngeal dilator muscle.  All of the above factors contribute to decreased ventilation during sleep. 

A lot of what is understood about the effects of nocturnal hypoxemia is due to extensive studies in individuals with underlying diseases, and these studies are not always conducted at higher altitudes.  One such study investigated the effects of nocturnal desaturation (SaO2 < 90% occurring for > 30% of the sleep study) in chronic obstructive pulmonary disease (COPD) patients without a diagnosis of sleep apnea.  The authors found higher rates of dyspnea, increasing rates of worsening COPD symptoms, poorer quality of sleep and health-related quality of life.  Another such study found that some patients with COPD experience increased transient arterial hypoxemia (TAH) during rapid eye movement (REM) sleep.   In this study, the authors observed that the study subjects experienced increased pulmonary vascular resistance (which can lead to pulmonary hypertension) and a few subjects experienced an increase in their cardiac output. The authors found that individuals could experience a decrease in this phenomena by using nighttime oxygen therapy.

Studies, such as above, do not assist in identifying healthy individuals that may need early intervention due to nocturnal hypoxemia at altitude.  What about the healthy individuals without underlying diseases?  In the study conducted by Gries and Brooks in 1996, the authors collected data from 350 patients.  Their recorded average low saturation in the study of 350 subjects was a reported 90.4% lasting an average 2 seconds.  This study was conducted at the Rainbow Babies and Children’s Hospital located in Cleveland Ohio, at an elevation of 653 feet (198 m). This is one of the largest studies done to assess normal oxygen levels observed during sleep, and the results, along with results from other studies are displayed in Table 1.  As of right now, there is no equivolent study for subjects at elevations like that of Summit County, CO, which is at an average of 9110 feet (2777 m). Aside from the normal physiological changes noted above, the rates of developing underlying central sleep apnea leading to systemic and pulmonary hypertension is unknown.  Further, there are no guidelines as to initiating treatment in patients that may be experiencing adverse effects of high altitude nocturnal hypoxemia, because there is a lack of data to establish baseline normal values observed at this elevation.  This leads to unnecessary sleep studies, and further involvement of a myriad of healthcare professionals that have no specific guideline to reference when approached by one of these patients. 

In order to further our understanding of the effects of high altitude and nocturnal hypoxemia in healthy individuals, like that of Summit County, there has to be preliminary and ongoing research in these individuals.  Dr. Chris Ebert-Santos is currently conducting an overnight pulse oximetry study, which aims to recognize which symptoms they may or may not be experiencing, that are related to high altitude or sleep disorders, so that they may receive treatment, feel better, and remain active. 

At this moment, initial study results reveal a decreased average low night oxygen saturation from that of the study conducted by Gries and Brooks.  In a sample of just 14 individuals, the average low SpOs recorded overnight is at 81.3%, which is 9% lower than that recorded by Gries and Brooks (Graph 1).  The study is also revealing a trend in lower night oxygen saturations in individuals that have lived at elevation for a longer period of time (Graph 2). These findings suggest the need to expand and build on the current study being conducted by Dr. Chris and her team at Ebert Family Clinic. If interested, you may apply in-person at Ebert Family Clinic, where you will be required to fill out a health questionnaire on your length of residence at altitude, medical history, and possible symptoms related to high altitude.  Your basic vitals will be logged at the appointment.  After the first study, you will then be rescheduled in 12 months for a follow-up overnight study to monitor for any changes.  Overall, this study is designed to help with an understanding on the potential impact of high altitude on healthy individuals that are acclimated, but not necessarily adapted, to this environment.

Robert Clower is a second year physician assistant student at Red Rocks Community College in Arvada, CO.  His undergraduate degree was in Biology, which incorporated both medical health science courses as well as independent research courses in general biology and ecology.  While attending school at the University of North Georgia, Robert served in the Army National Guard for a cumulative time in service of 8 years.  After completing his undergraduate degree, Robert gained medical experience as an operating room assistant, which included assisting support staff with surgical preparation and patient transport throughout the hospital for surgical appointments.  Outside of his studies, Robert enjoys snowboarding, hiking, snowshoeing, exercising and spending time with family and friends. 

Sources

Summit County Population Projections: Summit County, CO – Official Website. Summit County Population Projections | Summit County, CO – Official Website. http://www.co.summit.co.us/519/Population-Projections. Accessed March 3, 2020.

Tintinalli JE, Ma OJ, Yealy DM, et al. Tintinallis Emergency Medicine: a Comprehensive Study Guide. New York: McGraw Hill Education; 2020.

Gupta P, Chhabra S. Prevalence, predictors and impact of nocturnal hypoxemia in non-apnoeic patients with COPD. 52 Monitoring Airway Disease. 2015.

Lemos VA, Antunes HKM, Santos RVT, Lira FS, Tufik S, Mello MT. High altitude exposure impairs sleep patterns, mood, and cognitive functions. Psychophysiology. 2012; 49 (9): 1298-1306.

Cingi C, Erkan AN, Rettinger G. Ear, nose, and throat effects of high altitude. European Archives of Oto-Rhino-Laryngology. 2009; 267 (3): 467-471.

Acclimation, Altitude Science, Athletic Training, Health, High Altitude, High Altitude Training & Fitness

Altitude Training 101

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High elevation prompts physiologic changes in the body. As elevation increases, oxygen concentration in the air decreases; this is why some people suffer from altitude sickness when travelling to high altitude environments like Summit County, Colorado from a lower elevation. Training and/or living at elevation increases our red blood cell mass in order to compensate for the lower oxygen concentration, thus increasing our oxygen-carrying capacity. Red blood cells are like microscopic rafts that flow down the rivers of our blood vessels, picking up oxygen from our lungs when we breathe and then transporting it to all the muscles and organs that need it to function properly. For athletes, this physiologic concept can be used to their advantage in order to improve their performance. If they can train their blood cells to carry more oxygen by forcing them to grow in a more hypoxic (low-oxygen) environment, then they can have more oxygen available to their muscles to perform in any activity.

There is a modern training model that some athletes have adopted called “Live High, Train Low”. This means that the athlete performs high intensity training sessions at a lower elevation, but maintains general training and living at higher altitude. Your body begins making metabolic changes immediately when exposed to high altitude and hypoxia, but it can take a couple weeks for the maximum effect. Expert Dr. Gustavo Zubieta-Castillo, who spoke in La Paz, Bolivia at the 7th Annual Chronic Hypoxia Conference that Dr. Chris attended in 2019, claims that it takes him about 40 days to build up his hematocrit to be back to functional in La Paz which is situated at nearly 12,000 ft. All in all, the goal of living and/or training high, while including high intensity sessions at lower altitude, is to give your body enough time to build up some acclimatization to the hypoxic environment. Several studies in the last 25 years have taken various groups of athletes and placed them on different training regimens over 4 weeks. Some would live at low altitude and also train low, some trained low and lived high, and others trained high and low while living at high altitude. One study completed in 2008 concluded that athletes who either live high and train low, or live high while training low and high, showed about a 1.4% improvement in sea level endurance performance.

How high is too high, and how low is too low?

Snowshoeing above 9000 ft., Summit County, Colorado.

It was found in this same study, that there is in fact a “sweet spot” for implementing the “Live High, Train Low” paradigm. If subjects were living lower than 1800 m, there was not a significant improvement in athletic performance. On the other hand, if subjects were living too high, they could not adequately recover from training and therefore did not show improvement because their bodies struggled to keep up with the hypoxic environment. The best elevation to live and/or train at in order to increase RBC (red blood cell) production, RBC mass, and oxygen-carrying capacity is between 2100 m-2800 m, or about 7000 ft-9000 ft.

What does this mean for athletes in Summit County who live high and train high?

Great news! There are still major benefits to those who live and train in Summit Country, as well as for people who visit the mountains and train while they are in town. This is because of a physiologic process called autophagy. Autophagy is described as our cells’ process of degrading old proteins and damaged cell parts. This is a normal process that modulates cell survival, is important for cell renewal, and is also a promoting factor of exercise performance from altitude training.

When exposed to a hypoxic environment, our cells produce adaptive responses that ramp up autophagy and cell renewal elements. These responses include factors that promote skeletal muscle growth, boost skeletal muscle capillary concentration, and enhance coronary arteries (the arteries that feed your heart). Living and training at altitude is good for your heart and it can help build muscle while decreasing body fat mass. It also shows significant increase in cardiac output and strength of your heart stroke.

However, excessive exercise and especially excessive exercise at altitude can prove harmful to our skeletal muscle. It has been observed in male subjects running 20 km that the excessive exercise induces autophagy too much which leads to degradation of muscle protein, damage, and eventual loss of skeletal muscle all together. Therefore, just as there is a sweet spot for altitude training, it is also a good idea to monitor training in order to maximize the benefits of training in a place like beautiful Summit County.

So, how should I be training if I live in Summit County or if I am visiting for some time?

I had the pleasure of speaking with Mary Scheifley about this particular strategy. Mary is the owner of Peak One Fitness, a 24-hour gym in Frisco, Colorado (9000 ft.). She has over 20 years of experience in fitness and athletic training. She competed semi-professionally in mountain bike racing, and continues to bike today as well as cross-country ski, snowboard, weightlift, hike, and anything else that keeps her active. She loves Frisco and has found that being outside and active is almost spiritual. She is passionate about fitness and nutrition, and she works extremely hard to tailor her training regimens to each of her clients based on their individual needs or goals.

Cardio machines at Peak One Fitness, Frisco, Summit County, Colorado

When she trained people in Denver, she typically was running high-intensity aerobic classes. However, here in Frisco, she prefers to focus on strength and only include high-intensity interval training (HIIT) in short spurts. She believes that you don’t need to be over-exerting your body to see a positive response. She has a client who lives near sea level for most of the year where her main training regimen includes Cross Fit. When she comes to Frisco though, she can see a significant decrease in BMI and body fat index in just two months of lower-intensity training. Though frustrated that she cannot run on the treadmill as fast or as long as she can at home, by the end of her stay in Frisco, this client understands that difference of the elevation and appreciates the process that Mary provides for her.

Mary recognizes that fitness is not “one size fits all”. She typically likes to start people out at 80% of their maximum heart rate when exercising, but there are factors that may change this. Her clients that live in Summit County have already been acclimatized to the elevation so she can add a little to their 80% max heart rate because for them, 80% may feel like 70%. On the flip side, if you are visiting from sea level, she may have to decrease your 80% of maximum because of the hypoxia at elevation. Other factors that play a role in how Mary develops her training regimens include age, the client’s goals, their previous fitness level, and their overall reaction to altitude.

I also asked Mary about her experience with competition and professional athletes. Personally, she could tell that her endurance was superior to her competition when she raced at altitude against bikers from Denver. She also noticed that when she was in Denver, the racers there were stronger and bulkier than her. She also has experience training athletes who are preparing for competitions such as the Leadville 100 or who are professional skiers who tell her that it is more beneficial for them to come to altitude about 3 weeks prior to competition in order to prepare rather than just training at lower altitude. This is because their body will better adapt if they give it a little more time before competition while training.

At the end of the day, whether you are training for a competition, or just trying to stay healthy, being at altitude can pose challenges as well as benefits to our bodies. The following are some tips from Mary on maximizing your workouts at altitude without compromising your health and wellness.

Mary’s tips for athletic training and exercising at high altitude:

  • Increase water intake, even before you come to elevation. You should be drinking at least 3-4 liters of water per day.
  • Increase caloric intake. At altitude you are burning more calories than at sea level, and if you are wanting to train you need to fuel your body appropriately. Especially increase protein intake.
  • No alcohol. If you enjoy one drink here and there you should be fine, but if you are wanting to train at a high level alcohol should not be on the menu.
  • Add electrolytes. In addition to increasing water, you need to make sure you are replenishing your body with the salts it requires.
  • Take it slow. Maybe start with some yoga or moderate stretching before moving into running or HIIT classes. You may need to decrease your level of training by 20%.
  • Consider spending a night in Denver before heading up the mountain to Summit County. Dr. Chris has expressed this frequently to travelers and visitors of Frisco; it gives your body a chance to acclimatize prior to ascending to 9,000+ feet.
  • Don’t expect to be at your “home” level of endurance or fitness. Do not get discouraged if you cannot run your typical 7-minute mile, or you can’t easily warm up with a set of 10-15 squats. Your body needs to adjust, and you may need to just take it easy in the altitude. Ultimately, have fun and enjoy the beautiful outdoors!

Sarah Brzecezk is a 2nd year Physician Assistant student attending Midwestern University in Glendale, Arizona. She graduated from Northern Arizona University in Flagstaff, AZ with a Bachelor’s in Biomedical Sciences and then worked as a medical assistant in Internal Medicine prior to starting PA School. She is passionate about healthy eating and maintaining a physically active lifestyle, and she hopes to specialize in Orthopedics when she graduates this Fall. During her 6 weeks at elevation in Frisco, Colorado, she has enjoyed numerous hikes, two hut trips, yoga classes, and running in the gorgeous outdoors. Her goal as a provider is to help others overcome injury and illness in order to return to physical activity and athletics, enabling them to combat chronic illness and stay healthy for their future years.

References

Zhang, Y., & Chen, N. (2018). Autophagy Is a Promoter for Aerobic Exercise Performance during High Altitude Training. Oxidative medicine and cellular longevity, 2018, 3617508. doi:10.1155/2018/3617508

Brocherie, F., Millet, G. P., Hauser, A., Steiner, T., Rysman, J., Wehrlin, J. P. & Girard, O. (2015). “Live High–Train Low and High” Hypoxic Training Improves Team-Sport Performance. Medicine & Science in Sports & Exercise, 47(10), 2140–2149. doi: 10.1249/MSS.0000000000000630.

Stray‐Gundersen, J. and Levine, B.D. (2008), Live high, train low at natural altitude. Scandinavian Journal of Medicine & Science in Sports, 18: 21-28. doi:10.1111/j.1600-0838.2008.00829.x

Acclimation, Health, High Altitude, Mountaineering

High Altitude Hawai’i

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Rising 13,803′ (4207 m) from the surface of the Pacific Ocean, Hawai’i’s tallest dormant volcano, Mauna Kea, reaches well into its own unique high altitude environment. Measured from its base on the ocean floor, it is the tallest mountain in the world, about 33,000′ (10,000 m) in height.

A frozen Haleakalā silversword. PC: Lyle Krannichfeld & Pueo Gallery

You may never have thought to find a high altitude environment on the tropical island chain, but Mauna Kea is just one of four peaks that summit over 8,000′. The next three are Mauna Loa (13,679′), Haleakalā (10,023′), and Hualālai (8,271′), with Haleakalā (“House of the Sun”) on the island of Maui and the other three on the Big Island. Each of these dormant volcanoes is home to species of plants and animals found only in Hawai’i, many of them only found around their respective peaks.

Sacred lands, whose access was once restricted to only the divine rulers of Hawaiian society, Mauna Kea now hosts 13 observatories and research staff in addition to its foreign and local visitors, many of whom make the historic pilgrimage to the summit from sea level in a matter of hours via an access road established in 1964.

Visitors to Mauna Kea are advised to acclimate at the Visitor Information Center which sits at 9,200′, although a particular length of time is not specified. In addition to the more intuitive precautions regarding pregnancy or heart and respiratory conditions, visitors in Hawaii are also warned against making an ascent within 24 hours of having been SCUBA diving, which may not be so obvious. You can find this and more helpful tips consistent with current high altitude research on their Public Safety brochure, which includes information about symptoms of HAPE (High Altitude Pulmonary Edema, featured in a previous article, and very common in the Colorado high country).

Poliahu visits Haleakalā. PC: Lyle Krannichfeld & Pueo Gallery

In addition to the hypoxic conditions, Mauna Kea and its aforementioned counterparts are also prone to the dryness and weather systems we see in Colorado, with snowfall above 10,000′ as recent as the past few days, a visit from Poliahu, Hawai’i’s own goddess of snow, and the subject of songs and hula dances in her honor.

Roberto Santos is from the remote island of Saipan, in the Commonwealth of the Northern Mariana Islands. He has since lived in Japan and the Hawaiian Islands, and has made Colorado his current home, where he is a web developer, musician, avid outdoorsman and prolific reader. When he is not on a computer, you can find him performing with the Denver Philharmonic Orchestra, snowboarding Vail or Keystone, soaking in hot springs, or reading non-fiction at a brewery.

Acclimation, Altitude Science, Asthma, Child Growth & Development, Doc Talk, Health, High Altitude, Medicine

Dr. Chris’s HAPE Cheat Sheet

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Inflammation and altitude can cause low oxygen. Inflammation is commonly caused by viral infections such as colds or influenza, but can occasionally occur with bacterial infections such as strep throat or pneumonia. Low oxygen, or hypoxia, is the result of fluid collecting in the air sacs of the lungs, called pulmonary edema.

There are three types of high altitude pulmonary edema (HAPE).

  1. Classic HAPE, recognized for over a century. occurs in visitors to altitudes above 8000 ft (2500m) beginning during the first 48 hours after arrival. Symptoms include cough, congestion, trouble breathing, and fatigue, all worse with activity.
  2. Re-entry HAPE occurs in people who are living at altitude, travel to lower altitude, and develop symptoms during the first 48 hours after returning home
  3. High Altitude Resident Pulmonary Edema (HARPE) is a recently recognized illness that occurs mostly in children who have an underlying respiratory illness and live at altitude, with no recent history of travel. They have oxygen levels below 89 and lower but do not appear toxic. They are fatigued but rarely have increased work of breathing.
Parents are often worried their children won’t wear a canula for oxygen, but they don’t typically mind.

Treatment of HAPE is oxygen. There may also be signs of asthma or pneumonia which are treated with bronchodilators and antibiotics. Most people with pneumonia at altitude do NOT have hypoxia. All three types of HAPE can reoccur, but typically not with every arrival at altitude or viral illness. Many of these patients are told they have pneumonia again and again, or severe asthma, and are treated with inhalers and steroids. Usually, this adds nothing to their recovery.

A chest x-ray may show typical infiltrates seen with pulmonary edema, but in mild or early cases, can look normal. There is no blood test for HAPE. Oxygen should be used continuously at a rate that raises the oxygen saturation into the 90’s. Length of treatment may be as short as 2 days or as long as ten days

Most importantly, owning a pulse oximeter and measuring oxygen levels in anyone at altitude with symptoms of cough, congestion, fatigue and trouble breathing with exertion can keep people out of the ER and ICU. HAPE can rapidly progress to respiratory failure and death if not recognized and treated expediently.

Automotives at Altitude, High Altitude, Road Safety

i-70: Surviving Colorado’s Mountain Corridor

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Between Utah and Maryland runs over 2,000 miles of Interstate 70. Every year, caravans of cars commute via I-70 across the Rocky Mountain Continental Divide, right in the middle of Colorado, where road, weather and traffic conditions make for some of the most dangerous driving in the country. Year after year, fatalities are in the hundreds. Storms in every season are liable to obscure vision and make surfaces slick on steep grades and tight curves reaching well over 9,000′, and at speeds over 70 mph. Summit County, Colorado, surrounded by mountain passes up to 11,000′ and above, is the highway traveler’s gauntlet of possible peril. As another year comes to a close and Winter peak season gets into full swing, preparing to get up to this elevation is just as important as preparing for the altitude while you are here.

Born and raised at Colorado’s highest elevations, Chris Erickson is well into his fourth year working for the Colorado Department of Transportation (CDOT), up at the Eisenhower-Johnson Tunnel, as an Operator Dispatcher: he monitors traffic flow and conditions, deploying staff, services and heavy machinery when necessary. They operate the Colorado traffic management center from his roost right at the Continental Divide, which covers I-70’s mountain corridor. Over 200 miles of winding highway from Dotsero to Golden. He’s seen his share of disasters, so it occurred to me that he may have some valuable observations and advice for the rest of us.

The most intimidating aspect of his role is pretty much the same now as it was when he first started: Winter storms. When the snow gets heavy, they get out the big guns, snow plows deployed from every affected region, operating over stretches of 10 to 20 miles. There is a lot more to this than the drivers think, and I’ve seen cars trying to squeeze around side-by-side plows on icy roads, not aware that they are in formation to control traffic while effectively clearing snow and debris.

What is one thing you wish people would stop doing, knowing what you know now?

Obey the laws, observe speed limits. I wish semi drivers would stop catching on fire all the time. Their brakes catch on fire when they haul ass going down the hill [from the tunnel]. 

How could we forget about the variety of vehicles on the highway? You will often find yourself right next to literal tons of machinery flying down steep grades. Trucks jackknifing is not an uncommon sight, especially in the Winter, and there are enough runaway truck ramps to suggest these monsters losing their brakes is not uncommon, either.

What is one thing you wish drivers would start doing?

I wish people would educate themselves more on driving conditions in the mountains before they came up here. I wish people would educate themselves more on the difficulties of travel on this mountain corridor. There are just so many things: cliffs, rocks that fall all the time … we’re trying, but we only have so many plow drivers and we can’t be plowing every inch of the road every minute. For example, Silverthorne Hill, if that starts to get backed up, the plows can’t get through when they turn around and head back uphill. It’s difficult to manage this corridor with all the obstacles at elevation. People need to be more patient. 

When it comes to road and weather conditions, what do you consider to be the worst or most dangerous?

Black ice.

Stuck in Winter traffic at the Continental Divide

If you didn’t know, now you know. It’s in the local news year after year, but the very thing about black ice is its lack of visibility. Blending right into the black of the asphalt, this ice that has been sitting on the highway without warm conditions to allow it to melt is the cause of many accidents.

Animals on the road: moose, elk, deer … 

The sheer size of these animals rivals the weight of the largest SUVs you’ll see on the highway. Trying to predict the animal’s movement is useless, so it’s best to be prepared to come to a full stop when necessary. Road signs where animal activity are often present are up and down this corridor, and variable message signs (VMS) will always report the immediate presence of reported sightings.

Incidentally, writing the messages you see on these VMS is one of Erickson’s responsibilities. If you’ve paid any attention to each marquis in the mountain corridor (which you should be), you’ve read his work. He often jokes that he is the most widely read author in the state.

“Moose, marmots and motor homes: Spring Migration is on!” is the one he is most proud of, he says. I must admit, it’s pretty clever. When you put it that way, humans are arguably the most migratory animal on the planet.

Fortunately, drivers aren’t left completely without aid on this dangerous trek. CDOT provides a Courtesy Patrol that many are not aware of. This service will dispatch to the location of vehicles that need assistance moving out of the way of oncoming traffic to a safe space to troubleshoot all kinds of common car troubles from flat tires to running out of fuel. They won’t get you to your final destination, but they will give you up to a gallon of gas to move out of danger.

They’ll help you change a tire. They’ll give you a jump. They’d probably even let you use a phone or let you charge your own.

I ask Erickson if there’s anything else he’d like to share with drivers through the mountain corridor:

Buckle up. The worst wrecks often happen on clear, dry days with dry roads.

If you plan to be out there in the middle of the highway through the mountains, be patient, be kind, be courteous. There are long stretches of highway where cell service is unreliable. Being stuck roadside in the mountains requires more than the standard emergency kit. Temperatures are often below freezing in the winter, so bring gloves, hand warmers, blankets, washer fluid (don’t add water) for your car, water (don’t add washer fluid) for yourself, and warm, waterproof boots you can push a car in (worst case scenario). For more insight into how cars operate differently at altitude, check out our previous article on The Physiology of an Automobile.

Thanks for lookin’ out, Chris!

robert-ebert-santos

Roberto Santos is from the remote island of Saipan, in the Commonwealth of the Northern Mariana Islands. He has since lived in Japan and the Hawaiian Islands, and has made Colorado his current home, where he is a web developer, musician, avid outdoorsman and prolific reader. When he is not developing applications and graphics, you can find him performing with the Denver Philharmonic Orchestra, snowboarding Vail or Keystone, soaking in hot springs, or reading non-fiction at a brewery.


Acclimation, High Altitude, High Altitude Training & Fitness, Huts, Medicine, Mountaineering, Summit Huts, Wildlife

Section House in December: Moose Country

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Section House sits at 11,481′ (3499 m), on Boreas Pass, just south of Breckenridge, Colorado. It isn’t the highest hut in the Summit Huts system, but its unique location and history is what makes it one of the most challenging.

Many of the huts in the Summit and 10th Mountain Division systems sit on a hillside, below tree line, which provides a significant amount of weather mitigation. Section House is right at the tree line, on the pass, which means any wind and weather will likely be funneled right into you. And because you are in one of the highest counties in the United States, weather is highly variable.

I’ve done this hut in a blizzard before, arriving to find the padlock on the front door was frozen shut. That may have been the most I’d ever despaired in my life up until then.

Even in great weather, however, the temperature alone is a liability. When we set out from the trailhead this time, it was sunny and relatively balmy for December, in the 30’s (Fahrenheit). But the temperature in the shade can be several degrees lower, and as the sun sets below the Ten Mile Range, the temperature starts to drop by the tens of degrees really quickly.

The Stats

Distance: a little over 6 miles; GPS and some maps may differ by tenths of a mile. If you tell your friends 6, they may resent you.

Timing: the same hike has taken me a couple hours with no weight on my back besides water, on well-packed snow. This time, it took over an hour a mile, including frequent breaks, thanks to all the weight I was carrying and pulling. Additionally, we constantly had to redistribute weight among sleds and backpacks to relieve shoulders and keep sleds from tipping over. If you decide to pull a sled, keep the weight low and as evenly distributed as possible. The other very limiting factor was the last half of the trail was covered in at least a couple feet of unpacked, fresh powder. Our lead was breaking trail in snowshoes.

While the grade going back down to the trailhead isn’t steep enough to keep momentum without skating, it is significantly easier and faster, and took us half the time even after waiting for moose to safely cross our path.

Elevation gain: about 1100′.

Capacity: 12 people.

Packing

I’ve pulled a sled both times I’ve done this hut. I don’t regret it, but it is challenging at best in calm weather. Unless you are going for more than a couple nights, I’d recommend packing everything into a backpack.

Because the elevation gain is so gradual, the challenge with weight is the distance. Pack your weight so it will still be comfortable on your shoulders after three miles. The advantage of pulling a sled was having less weight on my shoulders, but after several miles, even minimal weight can dig into your muscles.

The only source of water around this hut is the snow you melt, which is why it isn’t open in the Summer season. Water purifying filters are the quickest way to refill all your containers at the hut, but you will want plenty of water for the hike in alone. Running out of water on the trail is dangerous. An added risk: when the sun went down on us after the first three hours in, the water in our CamelBak nozzles started freezing if we weren’t regularly sipping on them.

Bring a sleeping bag. Most huts I’ve been to have blankets and pillows on the mattresses, but this one does not. This is also one of the oldest and coldest cabins; built in 1882, it takes hours to heat up by wood stove, especially if no one has been in it recently.

Moose

Now forget all the advice I just gave you and center your whole packing strategy around how you plan to evade a charging moose.

This region is moose country: high, high meadows filled with willowy wetlands. They don’t care how cold it is. In the dead of night, one of us opened the front door to use the outhouse and a young bull was standing right in front. On the trail back, two different parties ran into a moose and her calf right on the trail. They are not in the way. You are on their trail.

But seriously, pack to be prepared for your comfort and sustenance on the trail and at the hut. The only thing you can do about the moose is give them a lot of space while avoiding any confrontational, jerky movements that may suggest any predatory intent. If moose perceive a threat, they are liable to charge, male or female. If they charge, drop everything weighing you down and pray-run (praying while running).

When we ran into the moose on the trail, we stayed over 50 meters away and just waited while the moose wandered further off our path. As soon as they were about 50 meters off our path, we proceeded with caution. But we waited for over 30 minutes, and would have waited longer if we needed to.

Skis vs. Skins vs. Snowshoes

This was the most highly contested logistical conversation among our party. In the end, four of us were on cross country skis (without skins), one was on skis with skins, one was on a split-board with skins, and one was on snowshoes.

This really depends on the conditions. Two weeks prior, three of us hiked the trail in boots, on well-packed snow after days of warm, dry weather. Days before we left for the trip, however, a series of storms blew several feet of snow in, which changed everything. Boots alone were definitely not an option.

Most people, who aren’t hiking to the hut, will stop and turn around at the halfway mark where historical Baker’s Tank stands. This means the trail up until that point will reliably be pretty packed down. Because of the recent snow, however, no one could be sure what conditions would be like for the second half of the trail.

Freshly-broken trail through fresh snow past the midway point to Section House.

Sure enough, Baker’s Tank to the hut was unbroken trail through deep, soft snow. Our lead, on snowshoes, was cursing all the way to the hut as he carved the path for the rest of us. But in deep snow, snowshoes are sometimes the most comfortable option for an ascent, especially if you are inexperienced on skis and skins.

The advantage to skinning up on a split-board or downhill skis is the width of the blades. They are wider than cross country skis, which makes balancing the extra weight more comfortable and stable.

On a packed track, cross country skis were relatively comfortable, if narrow. The boots are more similar to normal footwear, so are more flexible and comfortable than ski or snowboard boots. Price was also a determining factor: renting skis or a split-board can cost upwards of $45 per day at most rental shops. We found cross country skis for $10 per day at Wild Ernest Sports, above Silverthorne, and they worked well. One thing about cross country ski boots, however, is that they aren’t as well-insulated as downhill ski or snowboard boots. Trekking through deep snow in them requires much better waterproofing and insulation than we were prepared with.

Jupiter rising in the dusk on the way up to Section House.

As for skins, although the trail grade is very gradual, there is enough of a grade at times that you will be thankful for the traction that skins provide. So unless you’re on cross country blades, you’ll want some skins.

Altitude & Acclimatization

One advantage of carrying all the weight we did was that it forced us to make a slower ascent and take frequent breaks. These are two things you can do to minimize the affects of the altitude on any ascent. In our party, all but one of us have lived at an altitude over 7,000′ for at least one year. Most of us have lived over 9,000′ for several years. But this was the first hut trip over 10,000′ for three of us, one of whom flew in two days before from sea level.

Fortunately, no one in the group experienced any severe symptoms of acute mountain illness, and I credit that to our meticulous supervision of each person’s blood oxygen saturation as well as our slow ascent. The first night we were at the hut, the lowest oxygen saturation we saw was 85%, but most were between 85 and 90%, which, at over 11,000′ is not surprising. If some slow, deep breaths hadn’t brought oxygen levels up, I would have been more concerned.

Hitting kickers behind Section House.

As seems to be tradition on our expeditions, we arrived well after dark. But these days, sunset is at 4:30 pm. Luckily, the weather was calm, and the trail is quite obvious. Our biggest concern after dark was the tremendous drop in temperature. With no cloud cover and a recent cold front, it was well below freezing, and the only thing that kept us from freezing was the constant movement, which kept us progressing forward.

Ken’s Hut, next to Section House.

By the time we had all made it to the hut and built up a fire warm enough to kick our boots off, our socks were steaming in spite of how cold our extremities were. It took well into the night to heat up the hut, and we all spent the first night sleeping around the wood stove. Yes, it took seven hours for the last of us to make it to the front door of Section House, but the spring trip to the Benedict Huts outside of Aspen was still loads more difficult — and we didn’t even pull any sleds! The next day was windless, sunny, clear, and warmer outside than it was inside, which allowed us to get back out on our skis and snowboards to enjoy the backcountry without weight on our backs.

robert-ebert-santos

Roberto Santos is from the remote island of Saipan, in the Commonwealth of the Northern Mariana Islands. He has since lived in Japan and the Hawaiian Islands, and has made Colorado his current home, where he is a web developer, musician, avid outdoorsman and prolific reader. When he is not developing applications and graphics, you can find him performing with the Denver Philharmonic Orchestra, snowboarding Vail or Keystone, soaking in hot springs, or reading non-fiction at a brewery.

Acclimation, Altitude Science, Health, High Altitude

Effects of High Altitude on Appetite and Weight Loss

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It’s no secret that people living in high elevation areas such as Summit County seem to be healthier than the general population. But aside from the active lifestyles of many people who choose to live in the mountains, could there be other effects from living at high altitude that result in healthier outcomes?

Several studies have been conducted to examine the association between living at high altitude and weight loss. The overall findings suggest simply ascending to a higher altitude generally results in a reduction of weight. Whether this is due to relative low pressure hypoxia or increased physical activity is another question examined by researchers. Overall, a higher energy expenditure and decreased appetite have both been seen in those living at higher altitudes. One study found that those living below 500 m elevation on average had a 4.6 times higher risk of obesity compared to those living above 3000 m while controlling for differences in exercise, diet, and lifestyle.

Leptin is a hormone produced by the body that results in suppression of hunger. When our bodies secrete more leptin our hunger decreases. Multiple studies have shown that when people not acclimated to altitude are brought to higher elevation, leptin increases and appetite decreases. One such study took ten obese males to altitude and allowed them to eat as much as they would like and also did not allow them to exercise more than their regular amount during the study. After one week the study found the males consumed on average 730 calories less than what they usually ate at lower altitude. This resulted in a 3 pound weight loss over one week, and on average, they kept two pounds off after returning to their base altitude a month after the one week study was completed.

Leptin levels were increased for a time after returning to lower elevation and appetite remained lower than their baseline.

A follow-up study looked to determine exactly what factor of altitude causes this increase in leptin and used a hypobaric chamber to simulate a hypoxic environment similar to Mt. Everest. Subjects in this experiment lived in low oxygen conditions for 40 days and had an average of 16.7 pounds of weight loss and consumed 1,347 fewer calories. This study helped to suggest hypoxia as the driving factor for increases in leptin at altitude, and also showed an increased effect with the higher elevations.

Another possible factor leading to higher rates of weight loss at altitude could be linked to an increase in basal metabolic rate. Basal metabolic rate, or BMR, is the amount of energy or calories humans burn each day without accounting for exercise or general physical activity. In the same study that measured appetite and leptin levels in obese men brought to altitude for one week, BMR was also measured. These measurements showed an increased BMR at the end of one week at altitude and a return to baseline BMR two weeks after returning to lower altitude. This means that people tend to burn more calories just by being at a higher altitude, even without increasing exercise. This increased burning of calories paired with decreased appetite are likely the main driving forces between the weight loss seen in those newly introduced to altitude and lower weights and BMI’s seen in those that have lived at altitude for a long time.

With these findings of weight loss and overall decreased appetite when coming to altitude, it is important for visitors from low altitudes to be aware of these changes and plan appropriately. First of all, in order to avoid unintended weight loss, those new to the mountains should be aware of just how much they are eating. Apps such as MyFitnessPal are great for tracking your calories and can even factor in exercise such as hiking and skiing that may be causing you to burn extra calories. Based on your BMR and exercise, you can see just how many calories you should be eating to maintain your current weight. It is also essential to be aware of the kinds of food you are eating. In the studies showing decreased appetite, it was also shown that study subjects had a decreased likelihood of choosing carbs in their diet. Carbohydrates are an excellent source of energy and should be a main staple of the diet for anyone coming to altitude, especially if they plan to partake in any of the great outdoor activities places like Summit County have to offer. Good examples of healthy carbs include fruits, vegetables, nuts, and whole grains like quinoa, oats, and brown rice.

Ultimately, ascent to higher altitudes has been shown to cause a decrease in appetite, increase in basal metabolic rate, and an overall decrease in body weight. Some of these factors return to closer to baseline after acclimatization, but this can take weeks to months depending on the person. Anyone who is traveling to higher altitudes or who has recently moved to a higher altitude should take good notice of their general nutrition and calorie intake to make sure they are giving their body the fuel it needs to succeed in these unique conditions.

Mitch Tiedke is a physician assistant student at the Red Rocks PA Program in Arvada, Colorado. He grew up in Oak Grove, Minnesota and achieved his undergraduate degree in Genetics, Cell Biology, and Development, with a minor in Public Health from the University of Minnesota-Twin Cities. He has previously worked as a personal care assistant for developmentally delayed adults and as a nursing assistant on a pediatric oncology, GI, and med/surg inpatient unit. In his free time he enjoys hiking, snowboarding, biking, and movies.

References

Buchzik, B. (2014). Hypobaric hypoxia causes body weight reduction in obese males, double-blinded, placebo-controlled study. European Respiratory Journal, 44(58). Retrieved from https://erj.ersjournals.com/content/44/Suppl_58/P3650.short

Lippl, F. J., Neubauer, S., Schipfer, S., Lichter, N., Tufman, A., Otto, B., & Fischer, R. (2010). Hypobaric Hypoxia Causes Body Weight Reduction in Obese Subjects. Obesity, 18(4), 675–681. doi: 10.1038/oby.2009.509

Palmer, B. F., & Clegg, D. J. (2013). Ascent to altitude as a weight loss method: The good and bad of hypoxia inducible factor activation. Obesity, 22(2), 311–317. doi: 10.1002/oby.20499

Rose, M. S., Houston, C. S., Fulco, C. S., Coates, G., Sutton, J. R., & Cymerman, A. (1988). Operation Everest. II: Nutrition and body composition. Journal of Applied Physiology, 65(6), 2545–2551. doi: 10.1152/jappl.1988.65.6.2545

Voss, J. D., Masuoka, P., Webber, B. J., Scher, A. I., & Atkinson, R. L. (2013). Association of elevation, urbanization and ambient temperature with obesity prevalence in the United States. International Journal of Obesity, 37(10), 1407–1412. doi: 10.1038/ijo.2013.5

Automotives at Altitude, High Altitude, Road Safety, Technology

Physiology of an Automobile: Cars Need Oxygen, Too!

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There are seven establishments up here in Summit County, Colorado that offer auto maintenance. That means you will be on a waitlist weeks out to schedule any work you need done during the peak seasons. I finally got an appointment at High Country Auto in Frisco after my SUV started shaking when I drove over 40 mph. My undercarriage was caked in enough frozen mud and dirt that it was causing the car to rock. According to Carrie, who started the business with her husband Steve in 1998, this is a relatively common scenario in the high country. Something else she sees a lot up here is people from sea level putting water in with their washer fluid, which easily freezes on colder days. “The only way to unthaw it is to leave it in the garage overnight,” she says.

This prompted more conversation about how cars respond to the extremity of the altitude, incline and lack of oxygen up here.

“A lot of people up here try to run 91 Octane, the high-octane gas. But we don’t have enough oxygen up here to burn it. So they gum up their fuel injectors, they gum up their fuel system because they’re running too high of octane.

“The other thing people think that they can do is they think that they can chip their car to make it go faster … they try to bypass parameters on the computer to make it go faster. But it doesn’t work up here, because you need to have more oxygen.

“The other problem, too, is that they load their cars down with ten million people and all their [stuff], and then they try to go up the hills. And their car can only go so fast, because it can only take in so much oxygen, it can only process so much, plus they’re already fully weighted down. And then they hit altitude and their cars are [struggling].” (Insert Carrie’s imitation of a car struggling.)

“It’s like a big … 500 lb. guy going up four stories, and he gets up the first floor and he has a heart attack. Well, why? It’s because he’s exerting himself at altitude. It’s the same thing with cars. If a car has a little bit of a problem up here, and then you load it down with people and you try to get it to go up to 12,000, it overworks the car. And a lot of people don’t realize that cars have to work harder up here, just like people do.”

So what do you have to do to “prepare” your car for a trip up to altitude?

“Don’t overload it. And don’t push your car. Don’t try to go faster. When you’re going up a hill, be nice to your car. It’s like when you’re going down a hill, try to go into 3rd gear to let your transmission slow you down, take your foot off the brakes.

“The problem up here is people try to haul their trailers with Subarus. I’ve seen fifth-wheels being hauled with little, tiny cars. It doesn’t work up here … it can’t get enough oxygen for the car to process it. The biggest mistake people make up here is they overload everything.“

Another little thing you can do to take extra care of your car up here, she mentions, is let it warm up for two to five minutes when you first start it up in the morning. As the water freezes, all the fluids tend to gel, and it’s in your best interest to get these fluids warm again.

“When it’s 20-below, it takes a lot for the car to warm up. Just like us getting out of bed,” she laughs.

“This is not the place to push your car. If your car is gonna break down, it’s gonna break down up here.”

And if you’re an ASE-certified Master Technician, Carrie’s been looking to hire more mechanics for much more than they’re paid in the city. There used to be over 20 repair facilities in Summit County, but since it’s dwindled down to under 10, there is plenty of work for qualified mechanics up here.

And if you need your own blood oxygen, blood pressure, or undercarriage checked out, Ebert Family Clinic offers the former two for free!

robert-ebert-santos

Roberto Santos is from the remote island of Saipan, in the Commonwealth of the Northern Mariana Islands. He has since lived in Japan and the Hawaiian Islands, and has made Colorado his current home, where he is a web developer, musician, avid outdoorsman and prolific reader. When he is not developing applications and graphics, you can find him performing with the Denver Philharmonic Orchestra, snowboarding Vail or Keystone, soaking in hot springs, or reading non-fiction at a brewery.

Acclimation, Altitude Science, Health, High Altitude, Medicine, Surgery

Increased Risks of Orthopedic Surgery at Altitude

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With orthopedic surgeries becoming more common at higher altitudes, it is important that we understand the increased risks of surgery at higher elevations. Patients locally (Eagle, Summit, Pitkin, Grand, Lake and other high-altitude counties in Colorado) and those that travel from all over the world to undergo surgery by our orthopedic surgeons are at an increased risk for complications post-surgery. Patients that have surgery at a lower altitude and return to higher elevations post-surgery are also at higher risk for post-operative complications. These risks are higher for everyone having surgery at altitude regardless if you live at higher elevations or are from sea level.

High altitude is defined as 8-12,000 feet. However, increased surgical risks are seen starting at 4000 feet. There are no differences for increased risk if you are acclimated to the altitude (live here) or are visiting. The increased risk of surgery at high altitude is the same for all.

High altitude increases the coagulation state of blood (clotting ability) and hyperventilation (breathe out more than you breathe in), and oxygen saturation of blood and tissues is 10% lower at high altitude compared to low altitudes, leading to a hypoxic state. The hyperventilation state promotes the hypercoagulable state which causes the immune system to respond with a pro-inflammatory state. Acclimation does occur, we adapt, are able to breathe easier and function normally as our bodies make more red blood cells to compensate for the lower available oxygen in the air. However, the hypercoagulability of blood remains, because the hyperventilation state is sustained at high elevations (even if you live here). At high elevations there are physiological differences in pulmonary circulation (blood through the lungs), heart function, and fluid imbalances which induce dehydration that accompanies blood changes contributing to the increased risk of surgery at high elevations.

Risk factors for blood clots from orthopedic surgery for the general population include: decreased mobility or sitting around more, length of surgery (greater than 4 hours increases blood clot risk), joint replacements, smoking, diabetes, and other illnesses.

In general, there is a 40-60% chance of a blood clot following knee or hip replacement surgery. At altitude that risk doubles. There is a 3.8 times greater risk of thromboembolism (blood clots) for knee surgeries at high elevations. Total shoulder replacement surgery also demonstrates a 2-times greater risk of pulmonary embolism at altitude or 39.5%, compared to a 15% chance at sea-level. For rotator cuff repair of the shoulder, there is also an increased risk for blood clots. There is a 1.4-times greater risk for pulmonary embolism (blood clot in the lungs) for lumbar fusions at high altitude. Higher elevation is an independent risk factor for blood clots which lasts up to 90 days post orthopedic surgery.

Anesthesia at high altitude has its own risk. The sustained hyperventilation state at high altitude also leaves the patient more vulnerable to hypoxia and pulmonary edema with anesthesia. These risks can be minimized, however remain elevated for surgeries requiring general anesthesia above 4000 feet.

For patients returning to high altitude following surgery at lower elevations, there exists multiple risks due to hypercoagulable state, increased inflammatory response, and hyperventilation that higher elevations induce. Acclimatization to high altitude is lost within 2 days of being at a lower elevation and can take 3-4 months to achieve again. In as little as 2 hours after arriving at high altitude, the body initiates the above changes and this puts the post-operative patient returning to altitude at risk for a multitude of complications: dehydration, thromboembolisms, hypoxia, atelectasis, and pulmonary edema.

I recently spoke with a patient that grew up in Leadville (10,151 feet) and lives in Summit County (average of 7947 feet). She underwent hip surgery (twice) in Denver. Upon returning to Summit County, she developed high altitude pulmonary edema (HAPE) both times. When she underwent an ankle surgery in Edwards, the surgeon prophylactically treated her for high altitude sickness given her previous history. She did not develop HAPE, but was hypoxic and required oxygen therapy following surgery for a few days. She is a prime example that even those living their entire lives at altitude are susceptible to these increased risks from surgery.

These risks can be minimized by drinking plenty of fluids, using compression socks (TED hose) or sequential compression devices (SCDs), blood thinners (aspirin, Eliquis, or the like), doing ankle pumps and glute squeezes, and getting up and walking around every 1.5-2 hours for 10-15 minutes, all of which help decrease the likelihood that patients will experience blood clots following orthopedic surgeries.

To reduce respiratory or lung related complications it is important to do deep breathing exercises or incorporate the use of an inspirometer post-surgery, use supplemental oxygen if necessary, as well as continue to do these exercises after returning from a lower elevation for at least 2-3 weeks.

High altitude is an independent risk factor for orthopedic surgery complications. However, these increased risks have been seen in trauma patients and other surgical patients as well. The hyperventilation state, hypercoagulability, and elevated inflammatory response are not isolated to orthopedic patients, but exists in everyone living at and visiting higher elevations.

— Jessica Guthrie, BSN, RN

References

Cancienne, J., Diduch, D., & Werner, B. (2017). High altitude is an independent risk factor for postoperative symptomatic venous thromboembolism after knee arthroscopy: A matched case-control study of Medicare patients. Arthroscopy: The Journal of Arthroscopic and Related Surgery 33(2). https://dx.doi.org/10.1016/j.artho.2016.07.031

Damodar, D., Donnally, C., Sheu, J., Law, T., Roche, M., & Hernandez, V. (2018). High altitude an independent risk factor for venous thromboembolisms after total hip arthroplasty. Journal of Arthroplasty 33(8), 2627-2630. https://doi.org/10.1016/j.arth.2018.03.045

Damodar, D., Vakharia, R., Vakharia, A., Sheu, J., Donnally, C., Levy, J., Kaplan, L., & Munoz, J. (2018). A Higher altitude is an independent risk factor for venous thromboembolisms following total shoulder arthroplasty. Journal of Orthopedics 15(4). https://doi.org/10.1016/j.jor.2018.09.003

Donnally, C., Vakharia, A., Sheu, J., Vakharia, R., Damodar, D., Shenoy, K., & Gjolaj, J. (2019). High altitude is an independent risk factor for developing pulmonary embolism, but not a deep vein thrombosis following a 1 to 2 level lumbar fusion. Global Spine Journal 9(7) 729-734. https://doi.org/10.1177/2192568219828349

Tyson, J., Bjerke, B., Genuario, J., & Noonan, T. (2016). Thromboembolic events after arthroscopic knee surgery: Increased risk at high elevation. Arthroscopy: The Journal of Arthroscopic and Related Surgery 32(11), 2350-2354. https://dx.doi.org/10.1016/j.arthro.2016.04.008

Wani, Z. & Sharma, M. (2017). High altitude and anesthesia. Journal of Cardiac Critical Care 1(1), 30-33. https://doi.org/10.1055;s-0037-1604203

Acclimation, Alcohol at Altitude, Altitude Science, Doc Talk, Health, High Altitude, Medicine

Doc Talk: The Art of Saving Vacations

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In 1986, Dr. David Gray was asked to join a team of rafters on an exploration of the Yangtze River in China. Their goal, simple: to reach the undiscovered source of the Yangtze river and raft all the way down. Although simple is quite the understatement. The Yangtze River is the 3rd longest river in the world, and the source of the river is at approximately 19,000 feet (5791 m) above sea level. 

Dr. Gray, a young physician at the time, agreed to join the mission after being told by the mission frontman, Ken Warren, that “we want you there for trauma”. Dr. Gray, however, had an inkling that the high elevation could present some interesting challenges. He consulted with two pulmonologists, but at the time, understanding of treatment at high altitude was limited–he got little advice. With eagerness and reassurance that he would “have the final say on all things medical”, he began the mission. 

The team was comprised of an eclectic group of gentlemen. From 4 Chinese Olympic athletes, to a camera man from National Geographic, the crew set forth to uncharted territory. The took a bus up the first 14,000 ft, and they learned quickly about the effects of altitude. “Everyone was sick. I’m treating headaches with narcotics, treating vomiting with phenadrine, and guess what I had for pulmonary edema: lasix!” Despite the chaos, everybody improved and the crew trudged forward. 

In their slow ascent, there came a point when the snow was nearly six feet deep — vehicles were no longer an option. The rest of the mission would be on foot. On foot, with yaks carrying their gear, the crew moved up the glacier to what they presumed was the source of the river. The photographer from National Geographic, David Schippe, had not been doing well. As the mission progressed, Dr. Gray could hear crackles in the base of his lungs through a stethoscope and sent him down to receive medical attention. This was a case of  high altitude pulmonary edema (HAPE); he was diagnosed with pneumonia.

The rest of the crew reached the presumed source, “Tigers Leak Gorge”, which turned out to be one of the many Yangtze tributaries. On their decent down on “duckies”(blow-up rafts), they stopped at base camp and found David Schippe, the photographer that was supposed to have headed back to receive medical care. Their next checkpoint was at 11,000 ft; it was 600 miles away and they had no choice but to continue down with Schippe alongside. 

Unfortunately, this would be David Schippe’s last journey. “On the second day, Schippe started coughing; he gets very sick, and is put on IV. I said, ‘we need the helicopter,’ but there was no helicopter; that was all a lie. [Ken] had a short-wave radio, but he used the money for the emergency helicopter to pay his mortgage.” Dr. Gray, feeling the weight of this terrible deception, knew this would be the end of Schippe’s life.

We buried him on the river.

Dr. Gray distinctly remembers Ken Warren, the expedition leader’s announcement of their crew member’s death.

He said, ‘Dave’s dead. Suck it up, or you could be next.’

That was confirmation to Dr. Gray that this mission was not being run with any regard for crew safety. When they got to their checkpoint, Dr. Gray said “adios”. 

And so went Dr. Gray’s introduction to Altitude Medicine.

Fast forward to today, in a local brewery, Dr. Gray, equipped with the wisdom of 20 years of practice in Summit County, Colorado, after 25 years of Emergency Medicine in Corpus Christi, Texas, shares some of the essential knowledge for working in the hypoxic conditions of high altitude. An advocate for accessible and affordable health care, much of his practice involves bringing his medical services straight to his patients.

Has anything changed about what you put in your medical bag since you first started doing mobile health care?

No. I had a select group of medications I use that cover almost everything. I get an antibiotic prescription, so I can hand them their ZPak (my “go-to” medication).  I carry ventil, decadron, nubain (a synthetic narcotic) — it has some narcotic antagonist effects, so you have to be careful if you put someone on opioids on it, because it’ll put them in immediate withdrawal — Benadryl, and epinephrine.

First case of HAPE in Summit County?

He was from Scotland or somewhere in the British Isles. I sent him to the hospital, he gets in the ambulance, spends two days in the ICU in Denver, and $30K later, they send him back up!

Dr. Chris mentions that even physicians in Denver aren’t always familiar with high altitude care, and can order extensive testing for symptoms that are classic presentations of high altitude pulmonary edema. 

I got a guy from Austin; he was in his late 40’s. He had pulmonary edema, and  his O2 sats were maybe in the 70s. I said, ‘you need to go to the hospital, get out of the altitude, and go to Denver.’ He said, ‘I don’t want to leave my family, do I have to leave?’

I told him, ‘I’m going to work with you, but you have got to do everything I say. I’ll be back in the morning to give you another dose of decadron and you don’t get to sue me if this doesn’t end well.’

I see him the next day, give him another shot of decadron. He was one of the first people I allowed to stay at altitude. I wouldn’t leave anybody with that treatment if I couldn’t get him up to the high 70s.

Dr. Gray typically puts these patients on oxygen full-time at approximately 5 liters, monitors them closely, and finds patients’ oxygen saturations will typically go up into the 90’s.

I got confident with what I was doing.

He also makes a point that it’s essential to re-check vitals in these patients and to pay attention to symptoms. Too often, patients present with an acceptable oxygen saturation, around 93, and end up coming back hypoxic:

The oxygen can present normal initially because patients are hyperventilating! The respiratory muscles cannot maintain that work of breathing, and later, their oxygenation will drop! 

Dr. Gray and his own family have had their own experience with re-entry HAPE, as well:

We were back in Texas for a few weeks. I took them to the [alpine slide] back in Breckenridge, and Dillon (Dr. Gray’s son), who always got headaches, comes up to the car and throws up a bunch of red vomit. I told his sister, ‘Please tell me he drank a red soda before this.’ (He had.) Then we go home and he’s just feeling bad. I just figured, it’s his headache, or it’s a viral bug, then luckily, I put him in bed with me. At about 10 pm that night, he was coughing so much it was keeping me up. I put a stethoscope on him, and it was like a washing machine! His oxygen was 38!

I put him on five liters of oxygen and he quit coughing. The cough reflex was there because the lungs were trying to do anything to get more oxygen!

It’s not that the pulmonary edema was getting better quickly, necessarily; it took about three days for him to get better.

“It ain’t about water; it’s diet.”

What I believe happens when you come two miles in the sky as abruptly as people do: most Americans are dehydrated anyways. When they get here, the body goes into defense mode. It shunts blood and oxygen into your heart and kidneys and consequently … away from your stomach. Then, they (visitors) eat restaurant portion meals and greasy steaks on vacation. That’s why vomiting is sometimes the primary symptom. 

What I tell people is if you stop in a restaurant on your way up here, choose high carb, low fat, low protein meals — carbs are easy to transport through the system. Choose smartly, eat half of what they put on your plate, and take the rest home. The last meal should be at 5 pm. 

Also, alcohol is a mild diuretic at best! The real issue is that it’s a respiratory depressant! If you need to drink on this trip, drink in the morning!

Who gets acute mountain sickness? 

Young fit males. They come up here with a resting pulse of 52 beats per minute. A well-exercised person can’t get their heart rate up to counteract hypoxia. Then they ignore their symptoms because that’s what athletes do. As for athletes, I’ve given up on that. They go 100%, and they are not going to hold back.  

Another point that Dr. Gray emphasized was the seasonal factors: 

We see a marked difference in acute mountain sickness in Winter and Summer. You are by necessity in a hyper-metabolic state in the cold. Your body is working hard using oxygen to stay warm.  Plus, people are overusing muscles they haven’t used all year. In the summer, they come up in cars and ‘meander’ up. In the winter, they fly and ascend within hours. [Ages ago], you didn’t see any altitude sickness because they came on donkeys! Very slowly! 

And if you’re not sick by day two, you probably won’t be.

By the age of 50:

Everyone who lives here should sleep on oxygen. If you haven’t been here for generations, you need to be on night time supplemental oxygen. The only exception to this is in COPD patients due to oxygen deprivation driving respiration and CO2 retention.

I tell full-time residents, ‘you need an oxygen concentrator.’ It’s a night time problem. During the day, you’re ventilating. At night, you go into a somnolent state and your breathing goes down.

Muscles are healthier when you use them, that goes for the heart too. We (Summit county residents) are hyper-dynamic, cardiac-wise. If you supplement with oxygen at night, you keep the process of pulmonary hypertension from developing. 

Advice to the Traveler

Diamox: it changes your acid base chemistry, acidifying your serum, which, essentially, turns you into your own ventilator. Some people are aware of their increased respiratory depth and it may bother them. 125 mg twice a day, beginning two days before travel. Any dose greater than that will just increase side effects. 

The Water Issue: you can’t make up for chronic dehydration during the day. The biggest loss of fluid from the human body is insensible loss – moisturizing the air you breathe! Altitude also produces diarrhesis, as well as a lot of intestinal gas. The poor bacteria in your GI are also hypoxic.

Talking Altitude Medicine with Dr. David Gray

Dr. Gray opened his own practice in Breckenridge, CO caring primarily for travelers. With the motto “We save vacations,” he expresses a true passion for the demographics of the population and practice at high altitude. He developed his practice by networking closely with local ski industry workers, from lifties to ski shop employees, and provides fee for service immediate care to his patients. 

Autumn Luger is a physician assistant student at Des Moines University. She grew up in the small town of Bloomfield, Nebraska where the population of cattle vastly outnumbered humans. From there, she moved on to study biology and chemistry and eventually receive her bachelor’s degree at the University of Sioux Falls in South Dakota. She enjoys leisurely running, competitive sports, hikes in beautiful locations, attempting to bake, thrift shopping, and expressing creativity through art. Since being in Summit County, she has discovered some new interests as well: snowshoeing, hot yoga, and moonlit hikes.