Arriving to Denver, at 5,000 feet above sea level, starts a cascade of responses within our bodies. This is an example of allostasis, or how our bodies begin to adapt and acclimate to our surroundings in order to function properly. What does this mean? When first arriving to an area considered high altitude (5,000 ft above sea level), chemical receptors embedded in our skin sense the drop in pressure of oxygen and send messages to the brain to start hyperventilating (Young & Reeves, 2002). This rapid breathing causes our body to suffer from respiratory alkalosis (or increasing our body’s pH) by increasing the amount of positive ions in our blood (Battisti-Charbonney, Fisher, & Duffin, 2011). Even minor changes in our bodies pH can cause unwanted muscle spasms, headaches, and nausea. The increase of positive (ions) flow in our blood, opens up our cells to an influx of calcium which causes our blood vessels to dilate and relax. More calcium in the blood also causes a faster heart rate and more blood being pumped to the rest of the body. If left for a long duration, these changes can lead to acute altitude sickness. Instead, our bodies undergo acclimatization in order to adapt to different environments.
Acclimatization, or the ability to acclimate to certain environmental factors, starts with the bodies recognition of a rise in pH and responds with flushing the body of bicarbonate through urination. Bicarbonate acts as a buffer for high amounts of acid in our system, so by excreting it, the body returns to a neutral pH (Harris & Nelson, 2008). As for the cardiorespiratory system, the total blood volume circulating in our body decreases with increased urination and lower atmospheric pressure (Beidleman et al., 2017). The kidneys sense this change and release a hormone (erythropoietin) that sends a message to bone marrow to start producing more oxygen carrying red blood cells (Kaushansky, 2020). This process counteracts the lower pressure of oxygen in the atmosphere by giving blood the ability to carry more oxygen. These are all broad changes that occur to keep the body functioning in higher altitudes and continue to be more pronounced the higher the elevation is.
It is important to note that these system-wide changes occur between hours, days, and weeks. Differences can vary based on individual differences and height of elevation (Harris & Nelson, 2008). To limit the effects of acute altitude sickness, increased water intake and reduced activity can alleviate symptoms until the body fully acclimates. When planning your next fourteener, bring water and take it slow!
References:
Battisti-Charbonney, A., Fisher, J., & Duffin, J. (2011). The cerebrovascular response to carbon dioxide in humans. J Physiol. 2011;589(Pt 12):3039-3048. doi:10.1113/jphysiol.2011.206052
Beidleman, B. A., J. E. Staab, S. R. Muza, and M. N. Sawka. (2017). Quantitative model of hematologic and plasma volume. responses after ascent and acclimation to moderate to high altitudes. Am. J. Physiol. Regul. Integr. Comp. Physiol. 312:R265–R272.
Harris, N. S. & Nelson, S. W. (2008). Altitude Illness—Cerebral Syndromes. Emergency Medicince. https://emedicine.medscape.com/article/768478-overview
Kaushansky K. (2020). Hematopoiesis and hematopoietic growth factors. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 147.
West, J. B. (2012). High-Altitude Medicine. Am J Respiratory Crit Care Med, 186(12), 1229–1237. https://www.atsjournals.org/doi/pdf/10.1164/rccm.201207-1323CI
Young, A. J. & Reeves, J. T. (2002). Human adaptations to high terrestrial altitude. Medical Aspects of Harsh Environments. https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.175.3270
Hello Ian,
ReplyDeleteI really appreciate your post. I think that many people that visit CO and many other locations high in elevation forget that is it important to take it slow when it comes to having fun and that water is more important for consumption than other tastier options.
I will never forget the day I thought I was going to have to give CPR to a random stranger in a bar/restaurant while my family looked on. I had just recently taken my recertification course for CPR as required to get my update lifeguard certification. My family and I were enjoying our meals and all of sudden we heard a BOOM!, it was a mans head hitting the table and then another BOOM! followed as this man dropped from his seat at the table to the ground. Let me tell you my heart dropped into my stomach as his frantic family called out “does anyone know CPR?” My family all looked at me, and then I turned to my dad and said, “there is a fire department across the street.” Before taking off and running across the street I made sure that another citizen had stepped in to see if this strange on the ground was still breathing. Sure, enough the man was breathing shallow, and my dad and I ran off to go get more “qualified” care. As the fire fighters grabbed their packs and ran with us back across the street then man had woken up just as we walked into the door and proceeded to vomit across the floor. Frankly ruining the atmosphere of the restaurant, but hey he was okay and that all that mattered.
Listening to the commotion as the fire fighters checked his oxygen saturation and blood pressure the entire restaurant, sitting in silence, heard the female family member inform the fire fighter that he and a few other party members had just flown in. Furthermore, the fire fighters were informed that the man had very little water consumption since his time of landing and instead took part in several drinks during a tour of Coors Brewery. It was at this time that the fire fighters had determined that the man did not need to be seen at an ED but instead needed to acclimate, stop consuming alcoholic beverages and instead consume an exurbanite amount of water. This man needed to recover from and all too common case of altitude sickness. Dr. Todd Bull from UCHealth, director oversees the High-Altitude Clinic within the PVD program with Anschutz medical campus, states the 15% to 40% of visitors to high altitude will experience mild to severe spurts of altitude sickness. Dr. Bull also recommends avoiding alcohol at first as well.
Hydrate or diedrate, am I right?
By: Linda DuVal, for U. C. H. (2020, July 21). Know if you have altitude sickness and when to worry. UCHealth Today. Retrieved November 29, 2021, from https://www.uchealth.org/today/altitude-sickness/.