Category Archives: Acclimation

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

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.

Acclimation, Health, High Altitude, Medicine

Chronic Mountain Sickness

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Avinell Abdool

 

Chronic Mountain Sickness (CMS) is a pathological finding that is commonly found amongst individuals that have taken up permanent residence in high altitude environments (altitudes of over 8,200 feet)1. Clinical manifestations of CMS include but are not limited to the following1;

  • HA
  • Dizziness
  • Tinnitus
  • Breathlessness
  • Palpitations
  • Sleep Disturbances
  • Fatigue
  • Loss of appetite
  • Confusion
  • Cyanosis
  • Dilation of veins

 

CMS is the outcome of progressive loss of ventilation rate, which subsequently results in hypoxemia and polycythemia2. Polycythemia is defined as by excessive erythrocytosis (EE; Hb >/= 19g/dL for women and Hb >/= 21 g/dL for men) which along with a hypoxic environment can result in pulmonary hypertension2. In advanced conditions of Chronic Mountain Sickness there can be cor-pulmonlae and congestive heart failure2 .

A study was conducted in the University of San Diego by Dr. Gabriel Haddad that researched the adaption of the Peruvian population in high altitude conditions3. It was found that CMS is highest in the Andeans (approximately 18 %), lesser in Tibetans (1%-11%) and completely absent in the Ethiopian population3. From these data points it appeared that there was was a genetic correlation between CMS sufferers and ethnicity3. In addition, this finding added another factor that mystified the conclusive pathogenesis of CMS3. By understanding exact pathogenesis of CMS, it would not only benefit those who are at potential risk for the disease but also those living at sea level, where hypoxia plays a role in certain pathology ( such as stroke, cardiac ischemia, Obstructive sleep apnea and Sickle Cell Disease)3 .

A cohort of 94 individuals were gathered and were equally categorized into CMS and non CMS subjects3. These individuals originated from Cerro de Pasco, which has an elevation of greater than 14,000 feet3. Genetic tools and a custom algorithm were utilized and the researchers identified 11 regions on the genome that contained 38 genes that proved to be statistically significant3. Nine of the eleven genes were tested in fruit flies in hypoxic experiments3. The experiment consisted of fruit flies that had these genes and ones that did not have the genes3. It was concluded that individuals with these molecular adaptions were better able to adapt to physiological stress such as hypoxia when compared to individuals that did not have this adaption3. The results of this study allowed researchers to better understand the correlation between genetics and individuals who strive in hypoxic environments3.

 

 

Figure 1- D.melanogaster (fruit fly)3

 

 

Figure 2-Cerro de Pasco3

 

Bibliography

 

  1. Villafuerte FC, Corante N. Chronic Mountain Sickness: Clinical Aspects, Etiology, Management, and Treatment. High Altitude Medicine & Biology. 2016;17(2):61-69. doi:10.1089/ham.2016.0031.
  2. Chronic mountain sickness and high altitude pulmonary hypertension. High Altitude Medicine and Physiology 5E. 2012:333-346. doi:10.1201/b13633-23.
  3. Stobdan T, Akbari A, Azad P, et al. New Insights into the Genetic Basis of Monges Disease and Adaptation to High-Altitude. Molecular Biology and Evolution. 2017. doi:10.1093/molbev/msx239.
Acclimation, Child Growth & Development, Health, High Altitude, Medicine

Asthma and High Altitude: What You Need to Know

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According to the Centers for Disease Control and Prevention: one in thirteen people suffer from
asthma—that’s 25 million people in the United States alone, seven million of which are children under the age of
eighteen. 1 With populations in high elevation towns growing each year, more individuals with asthma will be adjusting
to life “up in the clouds.” While asthma sufferers may be at increased risk of developing a high-altitude illness such as
high altitude pulmonary edema (HAPE), is it possible for them to experience any benefits living at or traveling to
higher elevation? Before we dig in, let us examine what Asthma is and its related symptoms.

Asthma is an obstructive lung disease, meaning airflow is limited due to airway narrowing brought on by
inflammation and bronchial hyperactivity. The vast majority of patients with asthma will develop symptoms of
coughing, wheezing, chest tightness, and difficulty breathing before the age of five. When these symptoms present
intermittently, they can be controlled by a short-acting bronchodilator like Albuterol. For those with more persistent
asthma, an inhaled corticosteroid and (or) a long-acting bronchodilator may be needed in addition to
Albuterol. Exercise, cold weather, upper respiratory illness, stress, air pollution, and dust mite allergens are all known
triggers of an acute asthma attack. Is it possible that high altitude can actually minimize the impact of any of these
triggers?

One of the benefits of living at high altitude is consistently breathing the clean alpine air. Significantly lower
levels of house dust mites and air pollutants are found at high elevations; great news for allergic asthma
sufferers. 2  However, if one does not fall into that category, do not worry! A study published in the European
Respiratory Journal in 2012 showed that high altitude has beneficial effects for all asthma-types, especially those
refractory to steroids. Participants in the study had improved asthma control, improved lung function, and fewer sino-
nasal symptoms after 12 weeks at an altitude of 1,600 meters. 3 Given that even those with nonallergic asthma
benefited from high altitude treatment, there has to be something other than low levels of allergens at play. Several
studies have reported increased levels of catecholamines and cortisol in the bloodstream within the first two weeks of
staying at high altitude. 4 These hormones contribute to decreasing both bronchial inflammation and bronchial
reactivity which helps in controlling asthma symptoms. Furthermore, the lower viscosity of the air and lower oxygen
pressure reduce the resistance of airflow with inspiration and expiration, making it easier to breath! 2 Mountain living
may also yield a less stressful lifestyle. 3 Lower stress equals lower levels of the stress hormones that typically elicit an
inflammatory response, thus keeping asthma symptoms in check.

So, who is at risk when climbing to higher elevations? Anyone with asthma that is not well controlled prior to
to traveling to elevations of 1,500 meters and above could be at greater risk for having an asthma exacerbation when
they arrive. 2 However, little research has been done to determine who is more susceptible to Acute Mountain
Sickness (AMS) or more perilous altitude illnesses like HAPE. A group of researchers studying the effects of high
altitude and cold air exposure on airway inflammation in patients with asthma did incidentally find that patients with
lower oxygen saturation levels during a hypoxic exercise test were more likely to suffer from AMS when climbing to
high altitude. 4

What have we learned? HIGH altitude equals a LOW trigger environment for asthma patients. That means
it’s time to take that desired mountain vacation or tell your loved ones that suffer from asthma to finally come visit you
in the mountains! Keep in mind, the cold, dry air often accompanied by high elevations can incite an inflammatory
response, in turn, worsening asthma symptoms for some. We recommend visiting in the summer months. This
adverse reaction to cold air can be thwarted by using a face mask or other protective gear that not only warms but
also humidifies inspired air. 5

Disclaimer: If you or a loved one with asthma plan on traveling to high altitude be sure to check in with your primary
care provider first. If your asthma is not well controlled you may want to avoid any travel as it could increase your risk
of an attack.  Be prepared! Always carry your rescue inhaler and if you plan on going up in elevation be extra
cautious and bring inhaled or oral steroids as well. 

Laura Greenberg, PAS-II
Midwestern University Physician Assistant Program
Clinical Rotation—September 2017

Resources

  1. Centers for Disease Control. Asthma. http://www.cdc.gov/asthma/default.htm. (retrieved September 24, 2017)
  2. Mendenhall, A.M. & Forest, C.P. (2017). Out of air: Is going to high altitude safe for your patient. JAAPA, 30(8), 10-15.
  3. Rijssenbeek-Nouwens, L.H., Fieten, K.B., Bron, A.O., Hashimoto, S., Bel, E.H., and Weersink, E.J. (2012). High-altitude treatment in atopic and nonatopic patients with severe asthma. Eur Respir J. 40(6): 1374-1380
  4. Seys, S.F., Daenen, M., Dilissen, E., Thienen, R.V., Bullens, D.M.V., Hespel, P., Dupont, L.J. (2013). Effects of high altitude and cold air exposure on airway inflammation in patients with asthma. Thorax BMJ. 68: 906-913
  5. Cogo, A., Fiorenzano, G. (2009). Bronchial Asthma: Advice for Patients Traveling to High Altitude. High Alt Med & Biol. 10(2): 117-121
  6. Vinnikov, D., Khafagy, A., Blanc, P.D., Brimkulov, N., Steinmaus, C. (2016). High-altitude alpine therapy and lung function in asthma: systematic review and meta-analysis. ERJ open research, DOI: 10.1183/23120541.00097-2015.
  7. Grissom, C.K., Jones, B.E. (2017). Respiratory Health Benefits and Risks of Living at Moderate Altitude. High Alt Med & Biol. 00(00): 1-7
Acclimation, Child Growth & Development, Health, High Altitude, Medicine

Children’s Ears and Changes in Altitude

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Children’s Ears and Changes in Altitude Changes

The middle ear is where problems originate during changes in altitude like flying in a plane or driving over mountain passes. The middle ear contains Eustachian tubes that open and expand/contract to accommodate for changing air pressures in the environment. Adults have the knowledge and ability to actively “pop” our ears with intention so the pressure doesn’t become too high. Children that are too young to understand this process are at a higher risk for developing problems related to pressure related changes in the middle ear. So if you have descended on a plane or over a mountain pass and your child has been screaming the whole time…this is probably why!!! Their Eustachian tubes are also narrower and shorter than adults putting them at higher risk for problems equalizing pressure changes. Descending is usually when the most intense pressure changes occur but it can become a concern at any point in a trip.

Things you can do to help your baby/children:

  1. Encouraging them to swallow (this will help the Eustachian tubes to expand)
  2. Giving them a pacifier (in babies and much younger children this sucking can mimic swallowing and help to expand the Eustachian tubes)
  3. Give them a bottle (this is even more effective than a pacifier at opening the Eustachian tubes)
  4. If they are old enough to chew gum this can be very helpful!
  5. If they are old enough to follow directions but don’t have the natural instinct to pop their ears then have them pinch their nostrils closed, fill their cheeks with air, and blow out with the mouth closed directing the air toward the ears. This may have to be repeated several times to achieve effect. (These directions seem to help with understanding the technique)
  6. NEVER EVER LET YOUR BABY SLEEP DURING THE DESCENT. Allowing the pressure to build up without relieving it for an entire descent can put your child at risk for an ear drum rupture, especially if they have been congested or have a cold already. You should keep your baby awake for any descent and follow the above advice for pacifier or bottle feeding during this time.
  7. Decongestants are okay to pre-medicate adults for altitude changes but not the best option for very young children or babies. If you are planning on traveling with a congested or sick baby and have concerns about altitude pressure changes in the plane or mountains, speak with your healthcare provider before administering any medications.
  8. If your baby or child remains fussy, irritable, congested, feverish, or is pulling at their ears they should see a healthcare provider to assess if there is an ear infection (this may be related or unrelated to the altitude changes)

American Academy of Otolargyngology. (2017). Ears and altitude. Retrieved from: http://www.entnet.org/content/ears-and-altitude

Tara Taylor RN, BSN, CEN, CCRN

tarat@ebertfamilyclinic.com

Tara Taylor, FNP

Tara Taylor is a Family Nurse Practitioner at Ebert Family Clinic where she provides adult patient care and participates in high altitude research. She is a passionate advocate for mental health, women’s health, and affordable health care.

Acclimation, Child Growth & Development, Health, High Altitude, Medicine, Mountaineering

P.L.A.Y. AT ALTITUDE CAMPAIGN

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This summer, as part of my RN to BSN program with UCCS, I needed to complete a public health course with clinical. I decided on an unusual path by joining the team of pediatrician and public health activist, Dr. Ebert-Santos.

Dr. Ebert-Santos has been the primary care giver for my two boys, now 8 and 4 years old, since birth. I would venture to say that Dr. Chris, as we call her, is known by most families in Summit County. Not only are we a mountain community but we are a community committed to growing in mindful ways. A lot of thought goes into how we operate our community events and care for our families. Dr. Ebert-Santos has been very active on more community issues than I can address here. But, let’s include water quality, health insurance/coverage initiatives, and pretty much every community health walk for a cause, healthy community eating and garden initiatives, bike to work week, trail maintenance…you get the picture. For these reasons, I finagled my way into her office this summer.

Our community is one of the healthiest in the nation according to national statistics. We are one of the lowest on obesity, adult diabetes, and hypertension. For this reason, along with the beauty of the Rocky Mountains, we have a lot more people moving here than ever before. “Summit County has recently exceeded a permanent resident population of 30,000. This is a 28.7% increase in full-time residents since 2000” (Summit County Colorado, 2017).

One major health issue that Dr. Ebert-Santos is bringing to light with her current research shows that high altitude kids are often born at lower birth weights, catching up on the national growth charts within the first few years. These babies are not unhealthy by high altitude standards. The problem is that statewide and nationally, we have yet to set standards specific to high altitude children. Dr. Ebert-Santos is making a big push to address this.

Dr. Ebert-Santos is also the doctor most likely to check your newborn for wellness and release them home, safe and sound, following birth. Many of our mountain babies go home with an infant oxygen tank that you will see parents wearing as backpacks. Dr. Ebert-Santos has been collecting and analyzing data on high altitude kids for years now. At higher altitudes, we have lower air pressure and that means decreased bioavailable oxygen. While many people are aware that acute mountain sickness and high altitude pulmonary edema (HAPE) are potential obstacles to overcome when travelling up into the Rockies, many people do not know that our resident children, who haven’t even travelled down from altitude and back up, are also prone to these illnesses. High altitude pulmonary edema in children living at altitude can follow the sort of respiratory infections that kids are prone to catching as they make their way through school while their immune systems are developing. This is often entirely treatable with oxygen alone.

The problem Dr. Ebert-Santos has identified is that, assuming residents are acclimated and therefore unlikely to have HAPE, kids here are often diagnosed with pneumonia instead of HAPE. Treatment of pneumonia often involves a hospital stay with antibiotics and other medications on board. Dr. Ebert-Santos sees dozens of children each year who have what she would like others in the medical community to recognize as Mountain Resident HAPE. With proper diagnosis, these children can be treated with oxygen and improve within a matter of days. Awaiting recovery from pneumonia when there is no pneumonia present can be detrimental to children.

Dr. Ebert-Santos will have her research published this year in the Journal of High Altitude Medicine and Biology. I had the fortunate experience of working this summer, with Dr. Ebert-Santos and her dedicated team, to create a public health message relevant to her work. Office manager Meaghan Zeigler, who has a master’s in public health, was invaluable to my education there.  I was happy to find that our local oxygen companies were ready to join in this effort to educate the public. Big thanks to Summit Oxygen Inc. in Frisco, AlpinAire in Breckenridge, and AeroCare in Silverthorne! Below you can see the acronym I created to help high altitude families recognize the signs and symptoms of high altitude illnesses, including HAPE and Mountain Resident HAPE.

Stay safe and keep breathing Summit County!

Juli Joyce, RN

 

Acclimation, Health, High Altitude, High Altitude Training & Fitness, Medicine

High Altitude Training for Better Sea Level Performance

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High altitude training has become very popular among endurance athletes over the past few years. This trend has developed due to emerging evidence that chronic exposure to altitude improves overall performance at sea level. There have been multiple peer reviewed studies proving that physiologic changes which occur with high altitude training are beneficial for low altitude performance. The physiological changes that occur in response to decreased oxygen availability include increased erythropoietin response, leading to an increase in red blood cell production. These physiological changes lead to an improvement in oxygen carrying capacity and the delivery of oxygen to muscles. The ability to store iron is also increased. Even though these physiological responses appear to have beneficial effects, they can also be detrimental. Some studies have indicated a “detraining effect” associated with long term high altitude training. The low oxygen available at high altitude impairs the ability to train at high intensity, which can in turn negate the improvement in VO2 max.

Given the most recent data collection, the mantra of “Live High, Train Low” has been adapted. The idea behind this thought process is that the athlete is able to gain all of the beneficial physiological changes of training at high altitude, while still being able to train at high intensities at a lower elevation. In order to gain the highest advantage from high altitude training, a series of clinical guidelines has been published. The guidelines state that the optimal altitude at which to live and train is between 2000-2500m. Although altitudes about 2500m provide the beneficial physiologic effects previously stated, they are also associated with negative effects such as decrease in quality of sleep. The guidelines also recommend all training performed at altitude to be of low intensity, and to reserve high intensity workouts for lower altitudes. Furthermore, it is recommended that in order to maximize the benefits of altitude training, one should remain at altitude for a minimum of 21 days. Finally, it is recommended to compete either within 48-72 hours after returning to sea level or to wait approximately 14 days before competing.

Altitude training is nothing new to the elite athlete. This has been a tool used by many top athletes over the years in order to gain as much advantage as they can on the day of a competition. It is these specific guidelines which have been recently been published that give more precise strategies to optimize sea level performance. It is, however, always important to keep in mind that although the above guidelines can give both professional endurance and everyday athletes the best chance of improving their competitive performances, the response to high altitude training can vary from one individual to another.

Anna Miller, PA-S

Carly Stillman, PA-S

Red Rocks Community College Physician Assistant Program

Resources:

Constantini, K., Wilhite, D. P., & Chapman, R. F. (2017). A Clinician Guide to Altitude Training for Optimal Endurance Exercise Performance at Sea Level. High Altitude Medicine & Biology. 18(2), 93-101.

Acclimation, Child Growth & Development, Health, High Altitude, High Altitude Training & Fitness, Mountaineering

Can I take my child up a 14er?

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There are over fifty 14ers in Colorado. A 14er is a mountain with an elevation of at least 14,000 feet. If summited, these majestic peaks afford their climbers spectacular views of the surrounding landscape. Being that many people within Colorado – and those who come to visit – are active, a question often voiced by parents is: “Can my child hike up a 14er with me?” Unfortunately, there is no straightforward answer to this question and the simplest response is: it depends.

According to recent research, it appears that children are largely similar to adults when it comes to adapting to higher elevations. Research examined children’s short-term cardiorespiratory adaptation, incidence of acute mountain sickness, hypoxic ventilatory response, and maximal exercise capacity and found little variance between adults and children (Garlick, O’Connor, & Shubkin, 2017).

When CAN you take your child up a 14er? There are a multitude of factors that affect when and if a child can climb a 14er. For example, children develop and mature at different rates. This might affect whether your 11-year-old is able to climb a 14er, compared to someone else’s 11-year-old. Additionally, some children grow up being exposed to technical hikes and climbs, while others are not. This affects ability level and is certainly something to keep in mind (Provance, n.d.). Another factor to keep in mind is whether you’re child has an underlying condition. For example, conditions such as congenital heart disease, asthma, sickle cell anemia, an upper respiratory infection, or an ear infection can significantly increase the risk for high altitude illnesses (Garlick, O’Connor, & Shubkin, 2017, p. 6). Yet another factor is whether you live at altitude or are visiting from a lower elevation. There is a strong recommendation for those individuals traveling from a lower altitude to take some time to acclimate. Spending a night or two at an intermediate altitude is recommended. Additionally, be mindful not to overdo it when you do ascend to a higher elevation: stay hydrated and don’t overexert yourself. If you decide to climb a 14er, it is imperative that you give your body at least a few days to acclimate to the altitude (“How can I optimize my health at high altitude?”, 2016).

So, what’s the bottom line? Since it isn’t possible to place a concrete age on when it’s okay for your child to climb a 14er, it is ultimately up to you to know you’re child’s limits and to decide if such a challenging hike is right for you and them. The most important thing is to make sure that everyone remains safe.

If you do decide to set out on the challenge of hiking up a 14er, there are some things to remember in order to keep yourself and your child as safe as possible and ensure that the hike is an enjoyable experience for all (Kirkland, 2015):

  • Set out early: Summiting the peak by noon is recommended in order to avoid afternoon weather, thunderstorms, and potential lightning strikes.
  • Start slow and easy: It’s important for you to determine whether or not you’re child will be able to summit a 14er. Start with easy hikes and build up over time so that you have a good understanding of your child’s abilities.
  • Know the weather forecast: Check the weather before you set out to prevent getting stuck in a storm.
  • Clothing: Wear appropriate clothing. It is important to layer since it can be colder on top of the mountain. Additionally, it is important to wear clothing that protects you from the elements (including the sun!).
  • Protect yourself from the sun: The sun can be very strong when one is high up. It is very important to ensure that your child is adequately protected from the sun: sunscreen, clothing, etc.
  • Food and Fluids: Bring adequate nutrition and hydration.
  • Be prepared to turn around ahead of time: There are many things that could cause you to turn around. It’s very important to accept ahead of time that you might not manage to summit the peak and to accept that’s okay.
  • High altitude illness: It is incredibly important for you to know the symptoms of high altitude illness and be prepared to turn around should your child exhibit any of them. Symptoms of high altitude illness include: fussiness or irritability, refusal to eat, lack of energy, nausea and/or vomiting, dizziness, and light headedness (Provance, n.d.).

References:

Garlick, V., O’Connor, A., & Shubkin, C. D. (2017). High-altitude illness in the pediatric population: A review of the literature on prevention and treatment. Current Opinion in Pediatrics, doi:10.1097/MOP.0000000000000519

How can I optimize my health at high altitude? (2016). Retrieved from http://www.altitudemedicine.org/optimizing-health-at-altitude/

Kirkland, E. (2015, May). Taking kids to new heights: Hiking Colorado’s “14er” mountains. Retrieved from http://www.outdoorfamiliesonline.com/hiking-colorados-14er-mountains/

Provance, A.J. (n.d.). What age can my child start hiking fourteeners? Retrieved from https://www.childrenscolorado.org/conditions-and-advice/new-and-featured-articles/sports-safety/when-can-kids-start-hiking-fourteeners/

Rianne Smeele, BSN, RN, Regis University FNP Student

Acclimation, Child Growth & Development, Health, High Altitude, High Altitude Training & Fitness, Medicine, Mountaineering

Slumber Up: Sleeping at High Altitude

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Does high altitude affect sleep quality? The answer is that for some, it does. If you’ve ever quickly arrived to the mountains on a ski or summer getaway, you may have experienced fitful and non-restful sleep. Individual responses to high altitude may vary, however there is an understood physiological basis for sleep disruption at altitude.

 

A phenomenon known as “periodic breathing of altitude” is commonly experienced above 2500 m of elevation (about 8200 ft) in those not previously acclimatized [2]. This is a common sleep elevation in Colorado mountain towns such as Frisco, Colorado (proud home to this blog!). Periodic breathing of altitude may be more likely to occur as sleeping altitude increases. Here’s the science behind it:

 

The decreased atmospheric pressure at altitude results in less oxygen driven into the lungs and through to the bloodstream. The body attempts to compensate by increasing the rate of breathing (tachypnea), which also causes more carbon dioxide to be exhaled. Chemoreceptors sense the decrease in carbon dioxide and signal the body to stop breathing temporarily (apnea) to correct the imbalance. Alternating cycles of tachypnea and apnea continue to occur during sleep. The result is decreased REM sleep, which is a critical restful and rejuvenating phase [2].

 

Worried about your next sleepless night on a mountain trip? Fortunately, there’s acetazolamide (Diamox). It is a carbonic anhydrase inhibitor that works by eliminating bicarbonate in the urine, which is a base. The body subsequently becomes more acidic, and that acid in the bloodstream is readily converted to carbon dioxide. The body is “tricked” into thinking that there is plenty of carbon dioxide present in the bloodstream, and periods of apnea during sleep may be reduced or eliminated [3].

 

To help prevent periodic breathing of altitude, adults can take acetazolamide preferably starting on the day before ascent or on the first day at altitude. Adults typically take 125 mg twice a day until either 3 days at altitude has been reached or descent back down has occurred [1]. Ask your healthcare provider about what’s right for you. Consider acetazolamide next time you’re sleeping up high, and get that refreshing sleep that allows you to better enjoy the things you love at altitude!

 

-Justin Murphy, PA-S

Red Rocks Community College Physician Assistant Program

Clinical Rotation- May 2017

 

References

1) Athena Health (2017). Acetazolamide generic. Epocrates Online. Retrieved from: https://online.epocrates.com/drugs/12701/acetazolamide/Adult-Dosing

2) Gallagher, S. A., Hackett, P., & Rosen, J. M. (2017). High altitude illness: Physiology, risk factors and general prevention. Up To Date, Topic 181,  Version 20.0.  Retrieved from: https://www.uptodate.com/contents/high-altitude-illness-physiology-risk-factors-and-general-prevention?source=search_result&search=high%20altitude%20sleep&selectedTitle=2~150

3) Winter, C. (2016). Sleeping around: How to sleep at high altitude. Huffington Post. Retrieved from: http://www.huffingtonpost.com/entry/sleeping-around-how-to-sleep-at-high-altitude_us_5806da29e4b08ddf9ece1228?ncid=engmodushpmg00000006

Acclimation, Health, High Altitude, Medicine

Heart Attack Deaths at Elevation in Visitors

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Last year in Summit County, 23 people died of heart complications, 19 of which were visitors ascending to higher altitude.  Most of these visitors were in their 50s or older and died within one to two days after coming to elevation (Queen, 2017).

Acute exposure to high altitude over 2500 m can cause great strain on the body and is associated with significant alterations to the cardiovascular system such as tissue hypoxia and increased pulmonary artery pressures.  Although the concentration of oxygen at elevation is the same at sea level, the air is thinner causing less oxygen to breath.  At sea level the percent of effective oxygen concentration is around 20% where as in Summit County the percentage of effective oxygen drops down to 14%.  At higher elevation such as the ski areas the percentage of effective oxygen drops down to 13% (Queen, 2017).  As a result, the heart will pump faster to increase the delivery of oxygen to the body.  The cardiac stress at rest is minimal, however it can be significant during exercise.  Anyone with some degree of heart complication can worsen the stress on their heart when coming to higher elevation (Bach, 2013).

Hypoxemia due to high altitude can cause poor oxygenation of the lungs and constriction of blood vessels, causing an increase in pulmonary pressure and increasing hypertension.  Therefore, an acute exposure to high altitude can cause cardiovascular stress.  Residents of high elevation tend to do better because they have anatomical and physiological changes in their cardiovascular system that allows them to adapt to high-altitude chronic hypoxia (Hurtado et al., 2012).

It is recommended that any patients with cardiovascular disease who are from sea level and planning to come to elevation should slowly acclimatized themselves by staying in Denver for a day or two prior to going above 2500 m.  Patients who have stable heart complications should limit their physical activity for the first few days after ascending to elevation.

Hong Nguyen, PA-S

Physician Assistant Student

Red Rocks Community College

References:

Reference:

Bach, D. (n.d.). Altitude and the Heart: Is Going High Safe for Your Cardiac Patient? Retrieved March 28, 2017, from http://www.expeditionmedicine.co.uk/index.php/advice/resource/r-0034.html

Hurtado, A., Escudero, E., Pando, J., Sharma, S., & Johnson, R. J. (2012). Cardiovascular and renal effects of chronic exposure to high altitude. Nephrology Dialysis Transplantation, 27(Suppl 4), Iv11-Iv16. doi:10.1093/ndt/gfs427

J. Q. (n.d.). High elevation may be linked to visitor heart attach deaths. Summit Daily, pp. 1-4.

Acclimation, Health, High Altitude, Medicine

drugs and altitude:

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Consensus by International Federation on Drug Use at High Altitude

New Rochelle, NY, October 25, 2016—Drug taking at high altitude is variably intended to enhance performance, prevent or alleviate the debilitating effects of altitude, or for pleasurable use. In some cases, certain drugs can be advantageous and even life-saving, but many drugs lack evidence of benefit and carry risks of side effects or interactions. The International Climbing and Mountaineering Federation (UIAA) has published evidence-based guidelines advising on the safe use of alcohol, steroids, oxygen, erythropoietin, and many other types of drugs in mountain environments in an article in High Altitude Medicine & Biology, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free online on the High Altitude Medicine & Biology website.

An international team of researchers from Kuwait, Austria, United Kingdom, Germany, Switzerland, Nepal, Spain, France, and the Netherlands, led by David Hillebrandt, MB, BS, President, UIAA Medical Commission, coauthored the article entitled “Drug Use and Misuse in the Mountains: An UIAA MedCom-Consensus Guide for Medical Professionals.” They conducted an extensive review of the medical literature, trials, observational studies, and case series to assess the evidence available for drugs commonly used by mountain climbers. Their conclusions and recommendations cover a broad range of drug types including alcohol, anabolic agents such as androgenic steroids, adrenergic agonists, beta-blocking agents, erythropoietin, oxygen, glucocorticosteroids, benzodiazepines, and stimulants such as amphetamines.

“The use of drugs beyond those proven effective in preventing and treating high altitude illnesses remains very controversial among both physicians and climbers,” says Erik R. Swenson, MD, Editor-in-Chief of High Altitude Medicine & Biology and Professor, Division of Pulmonary and Critical Care Medicine, Veterans Administration Puget Sound Healthcare System. “This broad and comprehensive review of the myriad drugs used for various purposes in climbing will be useful to all concerned in decision-making about their use, determining the level of supportive evidence, and importantly their potential costs and adverse effects.”