Tuesday, April 21, 2015

Physiology of Everest

   Brett and I attended yet another science-y lecture at Linda Hall Library, this one with Dr. Bruce Johnson, professor of medicine and physiology at the Mayo clinic; and Conrad Anker, mountain climber extraordinaire and author. Soooo glad to have friends who love to nerd out at lectures as much as I do!
   Dr. Johnson spoke about the physiological changes of elite climbers at altitude and the similarity to symptoms and effects on the body as patients with heart failure. He performed a study on Anker and others as they climbed Everest--Anker's third climb. He concluded that people who have experience living at altitude, such as the famous Sherpas, and trained athletes with the greatest capacities for exercise endurance, such as Anker, are better able to deal with the adverse effects of hypoxia. But he did also say, "above 18,000 feet, you're not acclimating, you're tolerating." Meaning that even great athletes often yo-yo up and down the mountain before making their final ascent, and they don't stay long at the top.... Because they can't.
   According to Johnson, the carotid body and sympathetic nervous system's response to hypoxia is very similar to heart failure. Both produce an increased ventilation rate, significant changes in sleep architecture such as apnea, and pulmonary edema. He said that healthy climbers experience a state of homeostasis between their breathing and the collection of lung fluid, and it results in a net reduction of that fluid over time… A healthy response. He is using his findings to improve quality of life for heart failure patients.
   Anker was up next, and showed amazing still photography as well as time lapse video showing the changes in these mountains over time, due to both climate change, and the continual movement of the plate techtonics which created the Himalayas in the first place. He said that the mountains are being pushed up at the same rate that our fingernails grow every year, and that Everest is just a bit over 29,000 feet today. He talked about the historic climbing parties, beginning in the early 1920s, up to the first summit in 1953. The primitive gear and clothing that these men use made it all the more astounding that they even attempted to climb. He spoke of the great friendship and teamwork that developed between Hillary and Norgay, and how it enabled them to reach their goal together.
   All of this went a long way towards convincing me that perhaps I should attempt Everest someday. I know it is a significant financial and training investment. I know it is fraught with risk I wonder if my body could even handle the challenge presented by the conditions and the altitude. I guess there is only one way to find out, right? 
   On a slightly related note, I found a similarly interesting article from DAN (Diver's Alert Network) this morning about the physiology of diving: http://www.diversalertnetwork.org/health/heart/how-diving-affects-health?sf37523580=1