Category Archives: Acclimation

What happens to your body’s physiology when you move between low and high elevations?

Acclimation, High Altitude, High Altitude Training & Fitness, Medicine, Mountaineering, Technology

Packing for a Spring Hut Trip

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Another winter has come and gone, and now Spring is in Colorado. Which means Winter will be back a couple more times before the snow all melts.

We’ve organized a team of friends from San Francisco, Denver, and Colorado high country for a backcountry excursion to one of Colorado’s 10th Mountain Division huts. The Benedict huts, our dwelling for two nights tucked into the wilderness outside of Aspen, are almost 6 miles from the trailhead, with an elevation gain of over 2000 ft. : a formidable trek, even for the experienced. And experience in wilderness trekking is one thing, but altitude is a game-changer. We will be well over 8000 ft. long before we reach the huts, so preparation for such an undertaking requires as much attention to mental, physical and physiological condition as much as clothing, gear and rations.

Weather & Conditions

This has everything to do with the weather, so it’s important to be on top of tracking all the resources available to you. At the top of my list in this region is the Colorado Avalanche Information Center. They provide up-to-date reports for high-risk areas around the state according to a comprehensive and easy-to-understand rating system. When considering this information, I always remember that our trek will take us through several types of terrain, and thus, several types of conditions: in and out of trees, varying steepness and exposure (to sun, wind, precipitation, etc.), all kinds of microclimates and environments (wetlands, scree fields).

The Colorado Avalanche Information Center provides no shortage of visuals to aid your risk assessment.

As far as incoming weather patterns are concerned, one of the most popular and reliable forecasts endorsed by people who play outside in Colorado is Open Snow. Founding meteorologist Joel Gratz updates local forecasts regularly, and provides information on what to expect with the outdoor adventurers in mind.

For our upcoming hut trip, it looks like the storm we’re expecting will be warmer and milder than recent systems, with most of it heading toward the northern mountain region. That being said, however, I’m keeping in mind that any projected weather system can be just a few degrees colder, a few inches wetter, and a few miles closer and change conditions dramatically. So let’s talk about how we can anticipate this with …

Gear & Clothing

The Commute

In any season in Colorado, there are essential comforts I always pack to get me to and from any hut that requires a hike, and to keep me happy while I’m enjoying the site. Dead of Winter, Height of Summer alike, the sun and glare is liable to be more intense than anything you’ve ever experienced at sea-level, while at the same time, the temperature and lack of humidity can cool your body significantly, night or day. Depending on how strenuous the commute is or how active you intend to be even after arriving at your destination, you may be constantly shedding, then adding, then shedding, then adding layers, so keep it all very accessible.

For this particular trek, I’ll be in snow gear. Basically anything I’d wear snowboarding: snow pants, outer shell on top, hat, gloves. I want it to be warm and waterproof on the outside. Underneath this shell, I want layers that I can strip down to as soon as I start moving and sweating with a 40 -60 lb. pack on. Unless the storm turns out to be much more intense (in which case, I’ll keep the outer layers on), I expect my skin to be steaming, so I won’t want to be in much more than warm compression tights, a t-shirt, and a light pullover. Your outer shell is for blizzards and water-proofing, so whatever you are stripping down to should be significantly lighter. Also, sunglasses or goggles. The glare from snow is significant. I bring both, because goggles get way too hot while I’m trekking uphill.

Here’s the tricky part: What are you going to wear on your feet? This is where the weather forecast comes in. This time of year, after such a snowy winter, I’m expecting most of the trail to be covered in snow, and the storm moving in is likely to bring more. I will be scoping out the trail pre-storm, which will give me a much better idea of what to expect, but I’m preparing to have snowshoes or a split-board and skins strapped to my snowboard boots. Of course, skis with skins are another alternative. There is a very slim chance most of the snow on the trail will be melted down, in which case I would probably opt for waterproof boots instead, which I would expect to get pretty muddy.

Avalanche Gear

Whether it’s on the commute or while you explore terrain around the hut during your stay, there are some essentials you can pack for the worst-case scenario. I’ve gone into more detail in a previous blog, but standards that I will be keeping on me are a shovel, probe and beacon. But these tools are only a small part of avalanche preparedness. More important than the endless supply of technology you can invest in is knowing what conditions and natural phenomena to be aware of during your trek, and the Colorado Avalanche Information Center is a great place to start familiarizing yourself with these.

Cabin Comforts

There is only one limiting factor to this list, but it is considerable: how much you can carry. For six miles. Uphill. In snow.

Most of the huts in the 10th Mountain Division hut system are equipped with soft mattresses, small pillows, and blankets. The kitchens are stocked with utensils and dishes, there is toilet paper, paper towels, hand sanitizer and dish soap, as well as ample supplies of wood for burning in the wood stoves. So most of your weight will be food and drinks.

I always pack a sleeping bag and extra pillow, because the guaranteed warmth and comfort are worth it when you’ve spent your day being intensely active outdoors. And keep in mind you’ll want warm, dry layers to change into that you haven’t been hiking and sweating in all day. What do you want to be wearing when you’re lounging around the cabin reading, cooking, eating, playing cards, etc.? For me, this looks like socks, long underwear, a pullover and slippers that I can crush into my pack. And then what are you going to throw on when you have to go back outside into the dark cold of night to use the outhouse? Your Colorado uniform: a hoodie.

There won’t be running water, so you can’t expect to shower. When you’re in the wilderness for a long time and need to be discerning about how much weight you carry that isn’t food and water, bathing is of low priority. But for a short trip like this, I don’t mind bringing some form of wet wipes; they’re light-weight and take up very little space. Toothbrush and toothpaste should be obvious, though.

Medication & Acclimation

From climbing Mt. Fuji to Colorado’s 14er’s, I’ve noticed a lot of people bringing pressurized cans of oxygen. High altitude research has taught me just how temporary and unnecessary this trend is. Often, the most effective remedy for altitude sickness is 5 – 10 minutes on oxygen. I’m pretty sure you’ll blow through a whole can of gas-station aerosol oxygen before it does you any lasting good.

Avoid this by giving yourself time to acclimate before you get to extreme elevation. Ebert Family Clinic in Frisco, Colorado, specialists in high altitude research, always recommend keeping track of blood oxygen saturation with a pulse oximeter, and this is something small, inexpensive and very portable. Our team will be spending at least 24 hours at altitude before we embark on the trek to the hut. This way, members from lower elevations will have access to an oxygen concentrator to facilitate acclimation.

Physician and high altitude expert Dr. Christine Ebert-Santos recommends packing the following mediations for hut trips: Acetazolamide, Benadryl, Ibuprofen, an EpiPen, Acetaminophen, and topical antibiotic oinment. Of course, be aware of any allergies to medication in your party. It is also helpful to be aware of what symptoms you may expect to experience, should you start having trouble acclimating, including dizziness, nausea, hyperventilation, and fatigue.

Food & Water

This is where most of the weight you pack in will be. Again, no running water at the hut, so expect to boil all the water you need for drinking if you run out of what you bring. There are lots of compact water purification systems you can easily pack as well. For our six mile trek to the cabin, I will have a Camel Bak and a couple Nalgene-sized thermoses full of water tucked into my pack.

You don’t want to have to cook everything you bring, so snacks you can easily access and eat are essential, especially for the trail. For this particular hike, I expect to burn more calories more quickly than any other average day, so I want lots of nutrients per gram: pistachios, energy bars, jerky … And don’t underestimate the power of sugar and caffeine, this is precisely the kind of work your body acts quickly to convert these nutrients to energy for. And yes, I mean chocolate. (Fruit also contain a lot of valuable sugar, I’m told.)

While we’re at the cabin, we’ll have access to a propane stove, so we’ll be able to cook some hearty meals. Bacon, fruit, yogurt, bagels and cream cheese are all easy breakfast foods to pack. If you are fortunate enough to be on a hut trip with Dr. Chris herself, you will have pancakes at least once. It’s also easy enough to bring fixings for the most epic sandwich you’ve ever had: guacamole, sprouts, turkey, ham, greens, tomatoes, bread; and remember, it’s a good chance to justify all the calories you get from mayonnaise and mustard.

And speaking of calories and sugar, I feel like whiskey and beer were invented to accompany the warmth of a fire in a remote, mountain cabin. The good news is that you are sure to be carrying less out than you did in. The bad news is that hangovers are exacerbated by high altitude, so pay more attention to your consumption than you would at any lower elevation, and be sure to have plenty of drinkable water at hand.

Am I Ready?

Hut trips in Colorado are mentally and physically challenging, even in the best conditions. The more time you give yourself, the better. Know before you go and don’t go alone. And don’t be intimidated. I’ve successfully guided friends from sea-level who don’t consider themselves athletic to destinations well above the tree line without incident.

Always be checking in with your body, your team, and your environment.

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, Health, High Altitude, Medicine, Parkinsons

Increasing the Altitude to Decrease the Symptoms of Parkinson’s Disease

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By Jessica Thomas PA-S

 In May of 2009 Michael J Fox’s “Adventures of an Incurable Optimist” aired on ABC. This special chronicled his decision to battle the effects of his Parkinson’s disease with optimism and hope. During the production of this special he journeyed to the Kingdom of Bhutan. While in Bhutan, Michael J. Fox noted that his symptoms of Parkinson’s disease had almost completely vanished. 

 Bhutan lies between China and India, on top of the Himalayan Mountains. Bhutan is an extremely unique country since it is cut off from the rest of the world and has a desire to keep its culture unaffected by today’s modernization and globalization. Altitudes in Bhutan average 8-9,000 ft above sea level. When Fox’s parkinsonian symptoms decreased, he couldn’t help but wonder about the connection between the increased altitudes and the decrease of his symptoms. 

With more research into the topic it becomes apparent that Michael J. Fox was not the first person with Parkinson’s disease to notice a difference when in the high altitudes. According to Fred Ransdell, author of Shaky Man Walking, he has had two individual experiences where his tremors almost completely vanished. The first takes place whenever he is flying. Mr. Ransdell states that as the plane gains altitude he will remain completely asymptomatic until the plane lands. The second was when he was driving over a mountain pass at 9,000 feet elevation and he states that at that moment he noticed that his tremors were gone. How can this be? 

The first theory for why the increased altitude (>6,000 ft above sea level) decreases symptoms of Parkinson’s disease stems from the pH of our blood. When at higher altitudes we breathe faster and deeper in order to get enough oxygen into our lungs. When we breathe, our body discards carbon dioxide in proportion to oxygen we take in. Knowing this, it is understood that the increase in breathing also causes our body to get rid of more carbon dioxide from our blood which in turn will raise the blood pH making it more alkaline in nature. Naturally our blood is alkaline (approximately a pH of 7.3-7.4), otherwise death would ensue. Acids in our body are generally cell by-products, meaning that when our body is making energy or other necessities to life, they will give off acids. These acids are processed through the lymphatic system. When we have increased acids in our body the lymphatic system can get backed up. The back-up of acids in the body can cause stiffness, pain, and swelling. As the back-up worsens, deeper problems occur that affect the function of the cells and the tissues which can turn off hormone, steroid, and neurotransmitter production. Although this is an oversimplification of the process, it is easy to see that the more acidic the blood is, the more we may see increased symptoms of Parkinson’s disease. Correction of this acidosis is thought to preserve muscle mass in conditions like Parkinson’s and help with coordination. 

The second theory revolves around hypoxia and the main neurotransmitter that Parkinson’s disease effects. A study published in Springer titled Intermittent Hypoxia and Experimental Parkinson’s Disease found a link between hypoxia and the increase of dopamine synthesis. We know that atmospheric pressure reduces with altitude and with that so does the amount of oxygen. The reduction in the partial pressure of inspired oxygen at higher altitudes lowers the oxygen saturation of the blood which leads to hypoxia. But what does this have to do with parkinsonian symptoms? The results of this study revealed that a two-week course of intermittent hypoxia training in patients with Parkinson’s disease increased dopamine synthesis in old and experimental PD animals which restored the asymmetry of DA distribution in the brain. Parkinson’s disease is a progressive disorder that affects dopamine-producing neurons in the brain. When these neurons are destroyed, the production of dopamine severely decreases and we see symptoms such as tremors, slowness, stiffness, and balance problems

The Michael J. Fox Foundation for Parkinson’s Research received a research grant in 2018 to study the effects of altitude on Parkinson’s Disease. The study consists of two individual parts. The first part is a focused survey that asks individuals with Parkinson’s about their best and worst experiences with their symptoms during their travels in the last 2 years. The second part of the study will be an in-depth survey that with capture the travel experiences prospectively. 

Maybe we see the decrease in symptoms because of the hypoxia or maybe it is due to the increased pH of our blood, or maybe it is because of something we have yet to discover. With the new study from the Michael J. Fox Foundation on the horizon, answers to this question may be within our grasps. 

Jessica Thomas is a Physician Assistant student at Des Moines University in Iowa. Following graduation Jessica will be practicing family medicine in small town Iowa with an emphasis on preventative care and pediatrics. Over  the course of the last year she has had the joy of living and working in 6 different states around the country and has experienced many different climates and learned how to care for the ailments that occur in the different regions of the United States. When not at work or studying, you can find her reading on her porch swing, watching Hallmark movies in bed on Sunday afternoons, or spending time with her family and friends. 

References

F. R. (n.d.). Altitude and Parkinson’s disease. Retrieved from https://www.shakymanwalking.com/altitude-and-parkinson-s.html

Altitude in Bhutan. (n.d.). Retrieved April 12, 2019, from https://www.bhutantravelbureau.com/about-bhutan/township-altitudes/

Belikova, M. V., Kolesnikova, E. E., & Serebrovskaya, T. V. (1970, January 01). Intermittent Hypoxia and Experimental Parkinson’s Disease. Retrieved from https://link.springer.com/chapter/10.1007/978-1-4471-2906-6_12

Bloem, B. R., & Faber, M. J. (n.d.). Exploring the Effect of Altitude on Parkinson’s Disease. Retrieved April 12, 2019, from https://staging.michaeljfox.org/foundation/grant-detail.php?grant_id=1813

Ma, H., Wang, Y., Wu, J., Luo, P., & Han, B. (2015, September 01). Long-Term Exposure to High Altitude Affects Response Inhibition in the Conflict-monitoring Stage. Retrieved April 12, 2019, from https://www.nature.com/articles/srep13701

Parkinson’s and Nutrition. (n.d.). Retrieved from http://parkinsonplace.org/programs-services/parkinsons-and-nutrition/

Schwalfenberg, G. K. (2012). The alkaline diet: Is there evidence that an alkaline pH diet benefits health? Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3195546/)

Acclimation

Sleep at Altitude

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Reported Sleep Disturbances

Many travelers report a decrease of quality of sleep when traveling from sea-level to high altitudes. Newcomers to altitude typically describe trouble falling asleep and frequent wakings throughout the night.7 One study determined that 46% of 100 Iranian ski tourists reported frequent awakenings and other sleep disturbances such as insomnia during their first night sleeping at 3,500 m.5,7 Another study analyzed data from reports of 305 Chinese soldiers transported from 500 m to 3,700 m in Lhasa and found similar results. Approximately, 32% of the soldiers reported insomnia in the first night at altitude and 74% of 246 workers who were air-lifted to the South Pole at 2,835 m reported difficulty falling and staying asleep throughout the first week.1

Change in Breathing Pattern

Many theories state that the “periodic breathing pattern,” common during sleep at high altitude, is a potential cause of sleep disturbances. Periodic breathing is a form of Cheyne-Stokes respiration and reflects changes in neural signaling due to hypoxia and alkalosis during sleep.4 Hypoxia is a respiratory stimulant while alkalosis is a respiratory depressant.4 This mixed signaling is the source of the altered breathing during non-REM sleep encountered at altitudes over 2500 m. The frequency of periodic breathing during sleep increases as the altitude increases.3,4,7

Decreased Sleep Efficiency 

Compared with sea level, several studies have depicted that sleep at higher altitude is characterized by decreased sleep efficiency, prolonged superficial stages of sleep, and reduced stages of deep sleep.12 The image below is a qualitative representation of sleep structure recorded at sea level and at high altitude. The area encircled by the outer line reflects the time in bed and the area of the shaded inner pie chart the time asleep.7,13 The fractions of superficial stages of sleep are symbolized by “NR1&2,” the fractions of deep non-rapid eye movement sleep are represented by “NR3&4,” and the stages of  rapid eye movement sleep are exemplified by “REM.”

Fig. 1. Depicts a qualitative comparison of sleep quality at sea level vs. altitude > 1,500 m13

Shift in Brain Waves 

Everyone is aware of the importance of quality of sleep when it comes to memory processing. One study has associated a decline in sleep-related memory consolidation with the decrease in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects observed overnight at high altitude.15  Another study by Stadelmann et al. discovered that quantitative spectral analysis of frontal and central EEG derivations reflected an altitude-dependent decrease in slow wave activity.14

Daytime Performance

A study, analyzing sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m, discusses the association between sleep disturbances with poor performance in driving simulator tests.11 Studies performed at altitudes of 3800-3900 have revealed that supplementing with nocturnal oxygen improves daytime performance in neuropsychological tests, increases overall sleep quality, and reduces the occurrence of periodic breathing. 9,10 Although further studies are needed, the stated findings suggest that altitude-related alterations in sleep may negatively affect overall daytime performance.7

Can We Acclimate to High Altitude? 

Over time, research points to some sort of acclimation concerning sleep at high altitude; although research analyzing acclimation is very limited. Studies analyzing altitudes between 4,5559 m to 6,835 m have determined that the frequency of periodic breathing increased with the time spent at high altitude altitude.2,12 Opposingly, in studies at lower altitudes such as 1,650 m, 2,590 m and 3,450 m, periodic breathing decreased from the first to the second night.6,8 These observations suggest that there is an altitude-dependent effect of acclimatization on sleep structure. Interestingly, the same study that determined an increase in periodic breathing with time spent at an altitude of 4,559 also noted a decrease in arousal index and normalization of nocturnal oxygen saturation with increased time spent at high altitude.12 Stadelmann et al. determined that there was a statistically significant increase in the number of sleep cycles at higher altitudes with the longer the stay at altitude.14

Dr. Ebert-Santos’s Decision to Continue the Research

Despite recent advances in our understanding of sleep at high altitude, further research is needed to understand how demographics may alter sleep at high altitude, to determine the process of sleep-acclimatization, and to uncover the characteristics of sleep in local-highlanders.7 Dr. Ebert- Santos continues to be an advocate for the Summit County community regarding the effects of high altitude on health and has decided to pursue a study researching the effects of altitude on oxygen saturation during sleep of adults ranging from the ages 25-65 years old. Stay tuned for her process, her results, and her conclusions! 

Caroline, PA-S

References:

  1. Anderson PJ, Wiste HJ, Ostby SA, Miller AD, Ceridon ML, Johnson BD. Sleep disordered breathing and acute mountain sickness in workers rapidly transported to the South Pole (2835m). Respir Physiol Neurobiol 210: 38–43, 2015.
  2. Bloch KE, Latshang TD, Turk AJ, Hess T, Hefti U, Merz TM, Bosch MM, Barthelmes D, Hefti JP, Maggiorini M, Schoch OD. Nocturnal periodic breathing during acclimatization at very high altitude at Mount Muztagh Ata (7,546 m). Am J Respir Crit Care Med 182: 562–568, 2010.
  3. Erba P, Anastasi S, Senn O, Maggiorini M, Bloch KE. Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation. Eur Respir J 24: 303–308, 2004.
  4. Gallagher, Scot A. High altitude illness: Physiology, risk factors, and general prevention.  Up-to-date.Waltham, Mass.: UpToDate; September 20, 2017. www.uptodate.com. Accessed March 20, 2019.
  5. Jafarian S, Gorouhi F, Taghva A, Lotfi J. High-altitude sleep disturbance: results of the Groningen Sleep Quality Questionnaire survey. Sleep Med 9: 446–449, 2008.
  6. Kohler M, Kriemler S, Wilhelm EM, Brunner-Larocca H, Zehnder M, Bloch KE. Children at high altitude have less nocturnal periodic breathing than adults. Eur Respir J 32: 189–197, 2008.
  7. Konrad E. Bloch, Jana C. Buenzil, Tsogyal D. Latshang, and Silvia Ulrich. Sleep at high altitude: guesses and facts. Journal of Applied Physiology 2015 119:12, 1466-1480. 
  8. Latshang TD, Lo Cascio CM, Stowhas AC, Grimm M, Stadelmann K, Tesler N, Achermann P, Huber R, Kohler M, Bloch KE. Are nocturnal breathing, sleep, and cognitive performance impaired at moderate altitude (1,630–2,590 m)? Sleep 36: 1969–1976, 2013.
  9. Li P, Zhang G, You HY, Zheng R, Gao YQ. Training-dependent cognitive advantage is suppressed at high altitude. Physiol Behav 106: 439–445, 2012.
  10. Luks AM, van MH, Batarse RR, Powell FL, Grant I, West JB. Room oxygen enrichment improves sleep and subsequent day-time performance at high altitude. Respir Physiol 113: 247–258, 1998.
  11. Nussbaumer-Ochsner Y, Schuepfer N, Ulrich S, Bloch KE. Exacerbation of sleep apnoea by frequent central events in patients with the obstructive sleep apnoea syndrome at altitude: a randomised trial. Thorax 65: 429–435, 2010.
  12. Nussbaumer-Ochsner Y, Ursprung J, Siebenmann C, Maggiorini M, Bloch KE. Effect of short-term acclimatization to high altitude on sleep and nocturnal breathing. Sleep 35: 419–423, 2012.
  13. Rechtschaffen A, Kales A. A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. Washington, DC: Public Health Service, US Government Printing Office, 1968.
  14. Stadelmann K, Latshang TD, Lo Cascio CM, Tesler N, Stoewhas AC, Kohler M, Bloch KE, Huber R, Achermann P. Quantitative changes in the sleep EEG at moderate altitude (1630 m and 2590 m). PLoS One 8: e76945, 2013.
  15. Tesler N, Latshang TD, Lo Cascio CM, Stadelmann K, Stoewhas AC, Kohler M, Bloch KE, Achermann P, Huber R. Ascent to moderate altitude impairs overnight memory improvements. Physiol Behav 139: 121–126, 2015.
Acclimation, Medicine

Life Threatening Causes of Low Oxygen At Altitude

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Anyone who travels to areas of high altitude is at risk for high altitude pulmonary edema (HAPE). Classic HAPE symptoms include a dry cough and shortness of breath with activity; leading eventually to trouble breathing at rest. If left untreated, serious complications can occur. Many other conditions can mimic HAPE, and it is crucial for health care professionals to be able to distinguish between HAPE and other disorders that may cause similar symptoms. Illnesses that may present similarly to HAPE include pneumonia, a blood clot in the lung (pulmonary embolism), and chronic obstructive pulmonary disease (COPD) or asthma. Your health care provider will take a thorough history, but the following outlines the differences between HAPE and other similarly presenting conditions.

  • Pneumonia: In both HAPE and pneumonia, shortness of breath, fast breathing, and a fever occur. Normal oxygen saturations are above 90%, and if you have HAPE or pneumonia, these could be as low as 60 %. However, if you have pneumonia, you will feel a lot worse than if you have HAPE. HAPE typically responds to high flow oxygen and you will get better over a few hours. Whereas if you have pneumonia with low oxygen saturations, you will need immediate hospitalization.
  • COPD/Asthma: High altitudes may exacerbate your COPD or asthma. How providers tell the differences is through something called pulmonary function tests. This tests how well your lungs work. Your provider will have you breath into this device before and after being given albuterol. If your lung tests improve after the albuterol, then COPD or asthma are the more likely diagnosis. It is important to tell your provider if you have a history of COPD or asthma, and if you are a current or former smoker.
  • Pulmonary Emboli (PE): Patients with a blood clot in their lung typically have the same symptoms as HAPE but will sometimes also have chest pain when taking deep breaths. You may also have blood in your sputum and/or calf pain or swelling. You are more at risk for a PE if you have had a recent orthopedic surgery (such as a hip or knee replacement), you have an irregular heart rate, have a clotting disorder, smoke, or are on birth control. If you have these risk factors and additional symptoms, your provider may order a lab test called a d-dimer  and a chest CT scan to help distinguish between a blood clot or HAPE.

If you are experiencing any of these symptoms, it is important to go see a health care provider immediately. A thorough history and exam will help aid in the correct diagnosis and prevent any potential complications. And most importantly, will help you get back on track to enjoy your high-altitude vacation and living!

Miranda Bellantoni, FNP-Student

  1. Luks AM, Swenson ER, Bärtsch P. Acute high-altitude sickness. Eur Respir Rev 2017; 26.
  2. UpToDate. Distinguishing HAPE from Pneumonia 2018.
  3. Brusasco V, Martinez F. Chronic obstructive pulmonary disease. Compr Physiol 2014; 4:1.
Acclimation, Health, High Altitude, High Altitude Training & Fitness, Mountaineering

Rethinking Your Energy Supply

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On May 27th 2017, Adrian Ballinger summited Mount Everest without supplemental oxygen. This is an accomplishment that less than 200 people have achieved and followed a failure to summit the previous May of 2016. The 41 year old seasoned climber attributed his failures to the cold, which could have been aided by more muscle and fat content, better insulated jacket and gloves, but he wondered why his climbing partner, Cory Richards so easily made it to the top. Ballinger came to realize it that wasn’t his gear or body composition, but it was that Richards had a different approach to training and nutrition that gave him the edge to summit. Richards trained with a organization called Uphill Athlete that trains its athletes to become a fat burners. After hearing of Richard’s training regimen Ballinger was determined to pursue the same for a another summit attempt in 2017. Ballinger was a carb burner, which means he was relying on burning carbohydrates for energy. When he attempted to summit Everest being a carb-burner, he simply ran out of energy to fuel his body through the last grueling stretch. This was due to depleted glycogen levels that a carb-burner relies on. The average human can only contain enough carbohydrates to supply glycogen stores for about 45 minutes. Once your glycogen stores are depleted, you need to refuel, which in Ballinger’s case, would mean pulling a hand out of a mit in the frigid Everest air to replenish his energy every 45 minutes. This is also known as “bunking,” which means completely exhausting your energy supply, which is what happened to Ballinger. Richards on the other hand, was a fat burner. With alterations in Ballinger’s nutrition and training regimen, he was successful in 2017.

But what is a fat burner?

A fat burner is an athlete that primarily uses fat for energy, and this metabolic process is called fat oxidation. When an athlete is exercising on a typical high carb and low fat diet, they are burning about a 50/50 mix of carbs and fats during steady exercise. If that athlete decides to sprint at full speed being a carb burner or a fat burner, they are primarily burning carbohydrates, known as glycogen. This is the body’s evolutionary design to have instant energy to run away from the tiger when it storms your cave. In Ballinger’s scenario, the high intensity of Everest climbing was like a sprint, depleting all of his glycogen stores causing him to “bunk”.

Why is a fat-burning diet better for climbing?

Being a fat burner for a long distance endurance athlete is beneficial because it eliminates the need to refuel every 45 minutes, which is bothersome. Ever wonder why there is a plethora of fancy sugary “sports” drinks, gummies, and energy bars at sporting stores? They are called “energy” foods, because they are loaded with simple carbohydrates and sugar. On the other hand, a fat burner does not need refueling foods or drinks during exercise, but relies on the extensive supply of fat throughout the body. Even the most elite athletes with very low body fat will have enough to supply the body energy for a event. Picture this, there is a giant fuel tanker truck cruising on I-70. The truck has its own fuel tank which sits below the cab of the truck, which will be depleted in a couple hours. What if the truck could access the large tank that it’s hauling? That would give the trucker a enough fuel to drive for days! In the context of nutrition and your body, the small tank is the your glycogen storage and the large tank is fat storage. This is why some people can fast for days without skipping a beat; they have tapped into their fat supply.

What does it take to become a fat burner?

To become a fat burner, it’s quite simple: cut the carbohydrates. Well, I guess some may think it’s not so easy. You have to cut out pizza, bread, candy, tortillas, and all that good tasty stuff. When a person limits their carbohydrate intake to less than 10% of caloric intake, and increase fat consumption to 70% of their intake, their body shifts into a different mode of creating energy, by burning fat instead of carbs. The by-products of fat oxidation are called ketones. When a person converts to being a fat burner, it is called being in ketosis. This process may take a few days to weeks, which varies from person to person.

Is there any research behind this crazy idea of eating all the bacon and butter you can handle?

Yes, yes there is!

In the research article by Volek et al. (2015), the authors wanted compare a low carbohydrate ketogenic diet and a typical high carbohydrate diet in 20 elite endurance athletes. The authors tested the athletes with a 180 minute, moderate intensity (64% VO2 max), treadmill run.

VO2 max is known as the capacity of your cardiovascular system and its ability to distribute oxygen throughout the body. Higher means a stronger cardiovascular system, so 64% of your maximum effort would be considered moderate exercise.

A 64% VO2 max to you or I would be a brisk walk or a slow hike up that beautiful 14’er, but for these Ironman athletes it was an easy run on a treadmill. The authors compared the rate of fat oxidation and carb oxidation between the two diets, as well as their ability to recover and replenish their glycogen stores. The authors found that the fat adapted athletes had 2.7 times the rate of fat oxidation than the high carb diet athletes. The low carb group also had fat oxidation at higher VO2 max, meaning they could go faster without tapping into their precious glycogen stores. The study also found that after the exercise, the athletes in both groups had similar glycogen level in their muscle. This is significant because the classic rule of thumb with exercising is that you need a post-workout shake with protein and carbs to replenish your muscles, or your exercising efforts are gone to waste …

WRONG!

It turns out your body has its own way of replenishing its glycogen stores without the post-workout carb load. That means after you climb that 14’er, you don’t necessarily have to stop at the local brewery for carb-tastic IPA, but I won’t judge you if you do.

In another research article by Hetlelid et al., they wanted to compare the levels of fat and carb oxidation levels between nine well-trained (WT) runners and nine recreationally-trained (RT) runners during a high-intensity interval training session (HIIT). There was no difference in diets amongst the participants in the study. The study found that the WT runners had a three times higher rate of fat oxidation than RT runners and increased performance with higher VO2 max. The author attributed the increased performance due to the higher rates of fat oxidation. These athletes were consuming a normal carb-ful diet, which makes me wonder what the difference would have been if they were fat adapted.  

So, let’s get down to why all this mumbo-jumbo is important to your next trip to the high country. Many outdoor activities that we enjoy in the summer like hiking, biking, climbing, etc. all require significant energy to supply for all day fun. Take climbing a 14’er, for example. You will most likely be climbing for several hours, depleting your energy stores as you climb being on a high carb diet. You have to stop, refuel, start up climbing, stop and repeat. As a fat adapted climber, you could sail past your carb-comrades with ease, not depleting your glycogen stores all day, all while burning some of that winter Christmas cookie belly in the process. As we examined the two research articles, we also found that higher fat oxidation could mean higher VO2 max levels.

What does this mean for your next trip to high altitude?

That’s right, better usage of the less available oxygen in the high country and improving oxygen delivery throughout the body. If you want to be the best Balliger you can be on the mountains this summer, rethink your energy supply and consider life in the fat lane! 

So, here are some personal tips to becoming fat adapted:

-Give your body at least 3 weeks to become adapted before any highly strenuous activity, like climbing a 14’er

-Hydrate, hydrate, hydrate with water, and balance it with electrolytes

-Consult with your physician before drastically changing your diet

-Choose foods high in natural fats (eggs, nuts, olive oils, avocados, meat, fish, dairy) and stay away from unhealthy trans fats

-Intermittent fasting can help you transition into ketosis faster (12-16 hrs)

 

References

Hetlelid, K. J., Plews, D. J., Herold, E., Laursen, P. B., & Seiler, S. (2015). Rethinking the role of fat oxidation: Substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners. BMJ Open Sport & Exercise Medicine, 1(1). doi:10.1136/bmjsem-2015-000047

Volek, J. S., Freidenreich, D. J., Saenz, C., Kunces, L. J., Creighton, B. C., Bartley, J. M., . . . Phinney, S. D. (2016). Metabolic characteristics of keto-adapted ultra-endurance runners. Metabolism, 65(3), 100-110. doi:10.1016/j.metabol.2015.10.028

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Acclimation, Health, High Altitude

Mountains and Caffeine

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Effects of Caffeine at High Altitude

Visitors travelling to high altitude destinations have been known to avoid coffee/caffeine intake in order to avoid the dreaded symptoms of acute mountain sickness. The theory is that caffeine leads to dehydration, which then predisposes the individual to acute mountain sickness. A few symptoms of dehydration include headache, lethargy, confusion, weakness, nausea and vomiting. Similarly, symptoms of acute mountain sickness include fatigue, headache, nausea, vomiting, shortness of breath and difficulty sleeping. Although the symptoms of dehydration and acute mountain sickness are very similar, there is no evidence to support this claim that dehydration predisposes an individual to acute mountain sickness.1 Thus, the diuretic effect of coffee and caffeine are often exaggerated. Individuals that are accustomed to drinking 12 oz. of coffee rarely suffer from the diuretic effect of the beverage.1

The condition of acute mountain sickness is a response to hypoxia in the brain’s vascular circulation that causes an increase in the release of a neurotransmitter called adenosine. Adenosine binds to adenosine receptors found on the inner lining of cerebral blood vessels, causing vasodilation of the blood vessels in an attempt to increase the flow of oxygen and nutrient-rich blood to the brain. This increase in cerebral blood flow, however, is painful and causes many of the above-mentioned symptoms of acute mountain sickness.

Caffeine, in contrast, counteracts these effects of adenosine in the brain’s circulation by causing vasoconstriction of those cerebral blood vessels, decreasing blood flow within the brain. Therefore, it is likely that caffeine can help prevent the onset of acute mountain sickness because of its ability to decrease cerebral vasodilation in response to hypoxia at high altitude.1 Caffeine is included in several over-the-counter headache medications, such as Excedrin Migraine, exactly for this purpose.

While there is no clinical data exhibiting that caffeine increases the rate at which individuals acclimate to living at high altitude from sea level, physiologic studies suggest that caffeine is helpful in increasing ventilation and decreasing hypoxia. Caffeine stimulates chemoreceptors in the brain and carotid arteries, altering the brainstem’s respiratory center in the medulla oblongata to become more sensitive to low blood oxygen saturation. As a result of this increased sensitivity to hypoxia, the lungs and respiratory muscles unconsciously increase their activity to increase resting ventilation rate and increase blood oxygen saturation.

My Experience

During my six weeks at the Ebert Family Clinic for my pediatric medicine rotation, I measured my blood oxygen levels before and after drinking 12 oz of coffee. My results can be found in Table 2.

Table 2. Six-week average blood oxygen saturation pre- and post-consumption of 12 oz. coffee

Pre-coffee oxygen saturation average: Post-coffee oxygen saturation average:
Week 1 91% 94%
Week 2 90% 92%
Week 3 91% 93%
Week 4 92% 94%
Week 5 92% 93%
Week 6 91% 93%

While these results are an anecdotal summary of my own experience living at high altitude and drinking coffee for six-weeks, drinking 12 oz. of coffee showed an average increase of blood oxygenation of 2%.

Caffeine Study at Everest

One study conducted at the base camp of Mt. Everest (17,600 ft) studied the 24-hour effect of caffeine in black tea ingested by one study group compared to a placebo group that only drank water. Both groups ingested the same volumes of liquid in the 24 hours. The study found that both groups had identical urine amounts at the end of the study, suggesting that caffeine did not lead to dehydration. Additionally, the tea-drinking group reported less fatigue and better mood compared to the placebo group.1

Caffeine Withdrawal at High Altitude

Caffeine cessation in fear of dehydration while travelling to high altitude destinations often leads to an exacerbated withdrawal reaction from caffeine, mimicking the symptoms of acute mountain sickness. This is due to the up-regulation, of adenosine receptors in the brain that become uninhibited in the absence of caffeine. As a result, adenosine binds to the increased amount of adenosine receptors in the brain causing excessive cerebral vasodilation and subsequent headache, nausea, vomiting, weakness, lethargy and confusion. Therefore, regular coffee drinkers or any type of caffeine users should avoid abrupt cessation of caffeine intake while traveling from sea level to high altitude.1

Future Studies

The above mentioned studies have not studied the effects of caffeine in caffeine-tolerant vs. caffeine-naïve individuals, but a trial of caffeine in the form of either coffee, tea or pill would be worthwhile in otherwise healthy individuals suffering from symptoms of acute mountain sickness while visiting high altitude locations. Future studies would benefit from comparing the effects of caffeine on caffeine tolerant individuals and individuals who do not consume caffeine on a regular basis. However, individuals must always consult their health care provider to determine if it is safe to use caffeine prior to consumption of caffeine products.

Michael Peterson, PA-S

University of St. Francis, Physician Assistant Program

Acclimation, Health, High Altitude

Summit v.s. Saipan: Running

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Dr. Chris and Jacqueline, her niece from Guam, enjoy the Beach Road rec path in Saipan

When I lived on Saipan in the Pacific and visited my parents in Breckenridge I noted that my 10k  times were just as good at 9000 ft with humidity around 27% and temperatures in the 70’s as at sea level with 80% humidity and temperatures in the 80’s. Last month I had the same experience, in reverse: living at high altitude and visiting Saipan. Reading our blog on asthma, I attribute that to the lower viscosity of air and lower air pressure in the mountains compared to the high density of water vapor in the islands.  Both locations are beautiful and inspiring places to run!

Acclimation, Genetics, High Altitude

Tatum Simonson and Altitude Adaption: Physiologic and Genetic

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Tatum Simonson is a researcher at the University of California, San Diego who is interested in high altitude medicine: specifically, how high altitude adaptations can, over hundreds of generations, become part of our genes. I read one of her publications called Altitude Adaptation: A Glimpse Through Various Lenses. It delves into the research that has been done on physiologic and genomic changes of high altitude inhabitants and how these two factors coincide.

When looking at this information, it is important to remember that the reason high altitude is so much different from sea level or lower altitude is the oxygen in the air. It is not necessarily the percentage of the oxygen in the air, because the air is 20.9% oxygen at all altitudes. It is actually the lower air pressure that makes it feel like there is less oxygen. The air pressure comes from the weight of the air above us in the atmosphere. The further you go up, the less atmosphere there is above you to press down, and therefore less air pressure. Boyle’s law (whoa physics!) basically says that because of the lower pressure, in a given volume of air there are fewer molecules. Because there are fewer molecules of everything, the percentage of oxygen remains 20.9% but it feels like there is less oxygen in the air.

This is all to say that organisms have to adapt to this lower air pressure and less molecules in a given volume. Things that we know are affected include the saturation of oxygen of our blood. With less air pressure to drive the saturation of our blood with oxygen, sometimes it leads to low oxygen levels, or hypoxia. Hypoxia is detrimental because our body needs oxygen for our cells to function.

Simonson looks at 3 populations that have lived at high altitudes (3500m-4500m or 11,483ft-14,764ft) for hundreds of generations: Qinghai-Tibetan Plateau, Andean Altiplano, and Semien Plateau of Ethiopia (see map below). In her paper she goes further into the history of these populations and the uncertainty that exists with their timeline, but for our purposes just know that these populations have inhabited these high altitude areas for anywhere from 5,000-70,000 years.

Figure 1. Map with three locations where high-altitude adapted populations have lived for hundreds of generations. (Image modified from http://www.nasa.gov/topics/earth/features/20090629.html; low elevations are purple, medium elevations are greens and yellows, and high elevations are orange, red and white.) Tatum S. Simonson. High Alt Med Biol. 2015 Jun 1;16(2):125-137.

The first lens she looks through is physiologic, or how the body functions. There has been extensive research in this lens, summarized below.

  • Increased common iliac blood flow into uterine arteries in Tibetan and Andeans leads to increased utero-placental oxygen delivery at altitude, allowing less growth restriction. In other words, Tibetan and Andean populations have increased the blood flow to the growing fetus to help it grow more like someone living at lower altitudes. Furthermore, some studies show that their babies are actually bigger.
  • Tibetan and Amhara Ethiopian populations show the characteristic increase in hemoglobin levels that has long been associated with travelers to high altitude, but to a much lower extent than someone who has just traveled to altitude (i.e. native lowlander). This is in contrast even with Andean populations, who have higher hemoglobin levels than Tibetans. The Tibetan and Amhara Ethiopian populations don’t necessarily need a higher level of hemoglobin (molecule that carries oxygen) to get the oxygen that they need to their tissues.
  • Differences in the control of breathing: the hypoxic ventilation response is an increase in ventilation that is induced by low oxygen levels. The research shows that Tibetans exhibit an elevated hypoxic ventilation response while Andeans exhibit a blunted response.
  • Tibetan and Sherpa have been shown to have higher heart rates than lowlanders at altitude, as well as increased cardiac output, or blood that they are able to pump out of their hearts. There are also differences in the energy sources that some high altitude populations use for their heart to pump.
  • There are certain adaptive changes in skeletal muscle that Sherpa populations have made as well. Specifically, increased small blood vessels and increased maximal oxygen consumption.

The second lens is genomic, or the evidence for different genes in highlanders that have allowed them to survive and thrive at higher altitudes. One theory is that the ancestors of modern day highlanders had specific genes that gave them traits that were favorable for surviving at high altitudes. By matter of Darwinian selection, these genetic variants were passed down favorably over generations.

  • Many genes studies are involved in the hypoxia-inducible factor (HIF) pathway, which is involved in regulating various responses to hypoxia including making new blood vessels, making new red blood cells, iron regulation, and metabolism.
  • Specific genes studied include EPAS1 – has been associated with low (within sea level range rather than elevated) hemoglobin in Tibetans at altitude discussed above. EGLN1 and PPARA have also been associated with hemoglobin concentration changes.
  • There are many other specific genes that have been associated with specific adaptive changes for these high altitude populations.

It is important to realize the physiologic and genetic components of adaptation to high altitude environment. Simonson sums it up best herself:

“Understanding the associations between genetic and physiological variation in highlanders has additional application for understanding maladaptive and general responses to hypoxia, which remain an important biomedical component of hypoxia research. This is also of clinical value when considering distinct and shared hypoxia-associated genetic variants and combinations thereof may contribute to physiological responses in residents and visitors to the environmental hypoxia at altitude as well as chronic…or intermittent…states of hypoxia.”

I was happy to read this article and see how high altitude medicine may be affected by genomics in the not-so-distant future. Hopefully you learned something about hypoxia, physiologic and genetic adaptations!

Hannah Evans-Hamer, MD

 

Resources:

Simonson T. Altitude Adaptation: A Glimpse Through Various Lenses. High Alt Med Biol. 2015 Jun; 16(2):125-37. PMID: 26070057; PMCID: PMC4490743.

 

 

 

Acclimation, High Altitude

Reentry High Altitude Pulmonary Edema (HAPE) in High Altitude Residents!

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When High Altitude Pulmonary Edema (HAPE) is diagnosed, one often thinks of the diagnosis in relation to patients who have lived long term in low/sea level altitudes coming to high altitudes for the first time. However, a new study conducted by Santosh Baniya based out of the Himalayas suggest there is a subset of HAPE in which long term high altitude residents can fall ill to HAPE upon reentry to high altitudes after even a brief stay at lower altitudes.

Baniya’s study is based off a case report of an otherwise healthy pediatric patient who was diagnosed with HAPE after returning to his village of Manag (3500m) after a winter in Besisahar (760m)- a trip that was done multiple times in his life time with no complications. One change surrounding this diagnosis was a recent construction of a road between the two villages that decreased the usual travel time from a span of several days to a single day. The pathophysiologic explanation behind this phenomenon is thought to be caused by the descent of high altitude residents to lower altitudes, leading to a decrease in the red cell mass and a compensatory rise in plasma volume, which then in turn predisposes an individual to pulmonary edema once they return to high altitudes. Had the patient taken the original route of travel- it is likely that the gradual ascent would’ve allowed his body to acclimate to the altitude change and the red cell mass and plasma levels would’ve adjusted accordingly. However, due to the decrease in overall travel time the excess plasma levels led to pulmonary edema. Manifestation of this included shortness of breath, respiratory distress, and hypoxia (an oxygen saturation of 44% in this case). Treatment included high-flow oxygen, dexamethasone to help with air way swelling, and descent to lower altitudes which resulted in immediate marked improvement.

The remarkable aspect of this case- and the reason it was published- is that the doctors in a high altitude community failed to recognize a condition familiar to medical providers in the mountains here in Colorado. More importantly the clinical symptoms that we describe here are also pertinent to Mountain Resident HAPE and Trauma Related HAPE, which is often misdiagnosed by experts in Denver and other lower altitude communities outside of Colorado. Understanding the prevalence of this phenomenon is of utmost importance as an incorrect diagnosis of influenza, pneumonia or asthma could lead to fatal consequences- as oxygen does not treat these conditions. Proper recognition, diagnosis and treatment with oxygen, rest, and if severe enough, descent into lower altitudes need to be carried out promptly for effective treatment.

 

Garkie Zhu, PA-S3
MCPHS PA Program

Reference:

Baniya, S. (2017). Reentry High Altitude Pulmonary Edema in the Himalayas. High Altitude Medicine & Biology,18(4), 425-427. Retrieved January 23, 2018.

Ebert-Santos, C. (2017). High-Altitude Pulmonary Edema in Mountain Community Residents. HIGH ALTITUDE MEDICINE & BIOLOGY, 18(3), 278-284. Retrieved February 2, 2018.