Have you thought of what it would be like living in the mountains year-round? Medical professionals find it is important to look at what living at high elevations can do to the human body. One activity heavily affected is sleep. As mentioned in previous blog posts, visitors often have trouble falling asleep, staying asleep, and feeling rested in the morning. A recent study published in Physiological Reports measured the effects of sleeping patterns at high elevation. The participants experienced a simulated elevation inside a hyperbaric chamber. This mimicked sleeping at elevations of 3000 meters (9,842 feet) and 4050 meters (13,287 ft) for one night and then sleeping at sea level for several nights to establish a baseline for the research participants. Participants exercised for 3 hours in the hyperbaric chamber allowing researchers to observe how the lower oxygen concentrations affected their ability to perform strenuous tasks. The group that slept in a simulated 4050 meter environment had an increased heart rate that was 28% higher and an oxygen saturation 15% lower than the 3000 meter participants. When comparing sleep itself, the group at 4050 meters had 50% more awakening events throughout each night. This goes along with previous research on this blog that states that people who sleep at high altitude complain of insomnia and frequent awakening when first arriving at high elevation.

These numbers increase even more dramatically when compared to participants at sea level. Related symptoms reported during this study showed the incidence of acute mountain sickness occurred in 10% of the participants at a simulated 3000 meters, increasing to 90% at 4050 meters. As mentioned, the average heart rate increases and oxygen saturation decreases as the elevation increases. The baseline heart rate at sea level was 62 beats per minute, increasing to 80 at 3000 meters and 93 at 4050 meters. Ideally health care providers aim to oxygenate vital organs by keeping the oxygen saturation level between 92-100%. The lower the oxygen level the harder it is to keep organs properly profused. Age, health status, and place of residence are taken into consideration when examining study reports. Oxygen saturation at sea level was 98% decreasing to 92% at 3000 meters and 84% at 4050 meters.

As mentioned in a previous post by Dr. Neale Lange, sleeping at high altitudes can be hard due to the frequent awakenings and nocturnal hypoxia caused by the low oxygen levels at higher elevation. This study reiterates these findings with the results of the average oxygen saturation at 3000 meters being around 92%. Dr. Lange also found that sleep apnea was often more prominent and had more negative effects on the human body in environments that were lower in oxygen. This study agrees with that statement finding that people with sleep apnea had twice the hourly awakenings compared to those at higher elevation that did not have sleep apnea. Dr. Lange also pointed out that the contribution of hypobaric atmosphere to symptoms at altitude as opposed to pure hypoxemia is unknown. Frisco, Colorado is at an elevation of 2800 meters. Ongoing research at Ebert Family Clinic including residents and visitors along with laboratory studies such as this one can guide decisions about interventions and treatment to improve sleep and help us enjoy our time in the mountains.

References

1. Figueiredo PS, Sils IV, Staab JE, Fulco CS, Muza SR, Beidleman BA. Acute mountain sickness and sleep disturbances differentially influence cognition and mood during rapid ascent to 3000 and 4050 m. Physiological Reports. 2022;10(3). doi:10.14814/phy2.15175
2. Blog post: HOW DO YOU DEFINE A GOOD NIGHT’S SLEEP?:AN INTRODUCTION TO THE SLEEPIMAGE RING, AN INTERVIEW WITH DR. NEALE LANGE

Casey Weibel is a 2^nd year student at Drexel University, born and raised in Pittsburgh, Pennsylvania. He went to Gannon University for his undergrad and got a degree in biology.  Before PA school, Casey was an EMT.  He enjoys hiking and kayaking and is a big sports fan.