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
