Training Prep for Altitude....an early start

Dealing with aches and pains--and better yet, avoiding them--and fitness related to snowboarding. This is also the place to talk about helmets, safety pads, and goggles.

Re: Training Prep for Altitude....an early start

Postby wyorider » Wed Dec 02, 2009 9:22 pm

Pamela, Always drink high altitude beer, that's been my moto! :idea: And if you have to, run to the bar! Here in western wyo, you never want to let your high altitude stamina get dehydrated?!
No just joking, I just had my knee scoped from a wreck in Portillo, Chile a couple of years ago and have been hitting all the torture schemes my therapist has dreamed up and I feel great. I think it just take good hard exercise, like a bike and hills or running through the tall grass. Jackson Hole just opened last weekend and I sure can't wait to get on the hill. Snow is marginal but it will come. geezers rule
jpwyo
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Re: Training Prep for Altitude....an early start

Postby Rob3 » Sun Jan 06, 2013 2:20 am

I'm a physiologist, so I've thought about this a lot. I've also experienced pretty severe altitude sickness above 9,000 feet in CO; spent a week at Copper Mountain once and was on diamox each day and oxygen every night.

Much about altitude sickness is not understood. Certainly, the initial cause is the low partial pressure of oxygen at high altitude, but it's clear you cannot just hyperventilate to overcome it. The hemoglobin in your red blood cells simply cannot be loaded with as much oxygen as it can at sea level. And adaptation takes time because it requires that you synthesize MORE hemoglobin.

Moreover, hyperventilation will blow off too much carbon dioxide and the bicarbonate equilibrium (bicarbonate is the major buffer in blood) will shift toward CO2 and make you alkalotic (high blood pH, or, equivalently, low blood acid). If you were in a hospital this acid-base imbalance would definitely be treated.

One thing we DO know is that aerobic conditioning is NOT the answer. Good cardiovascular fitness is great for snowboarding, but being fit will NOT help you avoid altitude sickness. In grad school a bunch of physiology students were recruited to spend two weeks at altitude in Colorado and have lots of measurements made. The guy who was sickest at altitude was a basketball player who could run faster and longer than anyone else who went on the trip. He was completely miserable for the first week and a half. We simply do not know why some people are prone to altitude sickness and others are not.

It's also clear there is a problem with hydration, and it's clear too that diamox helps, but it's less clear WHY diamox helps. If you are dehydrated, why would you want to take a diuretic? Probably because diamox is a carbonic anhydrase inhibitor and its diuretic effect is secondary, not primary.

Carbonic anhydrase is an enzyme. It catalyzes one of the reactions in the bicarbonate equilibrium. With diamox in your blood, it would make chemical sense that you can hyperventilate (to get more oxygen in your system) without simultaneously exhaling too much CO2. This could keep you from becoming alkalotic (a good thing).

SteveH alluded to one of the most puzzling symptoms of altitude sickness: capillaries appear to become more permeable - or at least something changes that results in more water being filtered from the blood into the extravascular spaces of the body. This is like the pathological condition called edema. So not all the fluid balance problems of altitude sickness are caused by not drinking enough.

I've got other ideas about altitude sickness, but I imagine I'm already way over the top, so I'll wait to see if someone responds to this post before writing more on the subject.
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