Sunday, February 7, 2016

How To Prevent Attitude Sickness

In last week's post, I talked about altitude sickness and what to do if it strikes. This week, we look at the reasons why we get altitude sickness and how to prevent it.

The Earth's atmosphere is very thin. Compared to the size of our planet,
the atmosphere is as thin as the skin on an apple. You don't have to go
very high before you climb a substantial part of the way through that skin.

While nearly all of the Earth's atmosphere is below 100,000 feet, gravity compresses the atmosphere close to the Earth's surface. The air gets denser the closer you go to sea level. As a result, about half of all our planet's air is below 18,000 feet. 30% of the Earth's atmosphere is below 10,000 feet, and 20% is below 6000 feet. So just going from sea level up to 6000 feet, you have 20% less oxygen available to your lungs. Lake Tahoe, at 6230 feet, is higher than that. And all of the roads into the basin except one have passes over 7100 feet. The Mt. Rose highway crests at almost 9000 feet. It's very easy to get into territory with dramatically lowered oxygen levels. (Note that the percentage of oxygen in the atmosphere stays consistent at about 21%, but as the atmosphere thins, the oxygen "partial pressure" drops accordingly, and you get an equivalent drop in how much oxygen gets into your blood.)

If you're skiing at 10,000 feet and sleeping at 8000 feet (as in a Kirkwood vacation home), you are putting your body into a substantially hypoxic environment. Our bodies struggle when we don't have enough oxygen. The struggle can be very stressful.

If you want to acclimate without stress, what should you do?

A huge help is to spend a night at altitude before you start skiing or riding. Twenty-four hours without physical effort is even better. Staying in a lodging near 6500 feet (close to lake level) instead of one at 7500 feet also helps.

Where are the highest lodgings in the Tahoe area? The town of Kirkwood sits at 7800 feet, which is where you'll find most of its lodgings. But some of its homes - available on vacation rental websites - sit substantially higher. Many vacation homes on upper Kingsbury Grade - some near Heavenly's Stagecoach and Boulder access points - are also around 7800 feet. There are also vacation homes up above Incline Village that are at the same altitude. Don't avoid these wonderful places to stay, but consider allowing an extra day at that altitude before your first day of skiing.

At the minimum, try to get a night's sleep at altitude before hitting the slopes. You will find life at altitude much more comfortable.

How long does it take to fully acclimate?

It's been estimated that those of us who live at 6500 feet eventually produce extra blood (perhaps a pint or more) and we possibly develop the ability to carry more oxygen in our hemoglobin. How long does this adaptation take? Some estimates suggest one month. Anecdotally, many of us will attest to the fact that when we first came to Tahoe, we got out of breath just brushing our teeth. But after one month, life was back to normal.

What happens if Tahoe locals go down to sea level? We immediately start losing those adaptations. If we spend a month or more at sea level, we have to re-acclimate all over again when we come back up to Tahoe.

Bottom line? If you want to prevent altitude sickness, go slowly. Stay near the lake level, especially during your first day. Sleep overnight before doing lots of exercise. If you're planning on riding multiple areas, start with areas at lower elevation, such as Homewood. Or the lower slopes at Squaw Valley. As the days progress, move to the other areas, saving the highest areas, Mr. Rose, Heavenly, and Kirkwood for last.

These simple steps will give you a great winter vacation!

P.S. People who've lived for thousands of years in the highest areas of the world, like Tibet, the Andes, and the Ethiopian highlands, have evolved several different adaptations including genetic differences that allow them to better absorb oxygen at high altitude. So don't think, "Hey, sherpas can hang out at 16,000 feet, so I can too...!"

P.P.S. If you want to see dramatic evidence of the effects of thin atmosphere on living things, just look at the WhiteBark Pines at the top of Sky Chair at Heavenly (10,000 feet above sea level). Talk about scrawny plants desperately trying to eek out a living where the air is so thin.

These Whitebark Pines are old but no taller than the skier who's using them for slalom poles.
Photo courtesy of

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