Getting High

Winter sports are often enjoyed at altitude. Going to high elevations pushes all your cardiovascular systems to respond. Are you ready?

The partial pressure of oxygen declines progressively with altitude, dropping to only 50% at 5,000 meters while the concentration of oxygen in the air stays the same, 21%. The body is unable to access the amount of oxygen normally needed without dramatically increasing breathing, blood flow, and sometimes blood pressure.

Relative hypoxia, or lowered oxygen concentration in your blood, occurs when you cannot adapt fast enough to the lowered partial-pressure of oxygen. Certain behaviors inhibit your adaption mechanisms.

Smoking brings carbon monoxide into the lungs, binding the hemoglobin that carries the oxygen to the tissues. Smoking three cigarettes effectively raises you to the equivalent of 1,500 meters of elevation. This not only makes you breathe even harder to get enough oxygen; in trying to conserve oxygenated blood for the brain, the cardiovascular system distributes blood away from the peripheral parts of the body. As a result, your muscles don’t work as well. And higher levels of carbon monoxide and hypoxia lower visual acuity immediately. You simply don’t see as accurately.

Alcohol also shifts the dissociation curve of oxygen, making it less available to all the tissues.

If you have heart disease, or arteries that are calcified or restricted by plaque deposition, your system may not be able to distend and contract effectively enough to balance the increased load.

If you have lung disease—or simply a cold—your ability to expand your lungs and fill their small alveolar spaces with fresh air may be restricted. Clearing the lungs before going to altitude helps, if possible. Once up there, using inhalers, nasal washes, and decongestants all improve your reactivity to the altitude stress.

But you have to pay attention to more than just the oxygen concentration. The dry air at altitude dehydrates all people, and few down landers remember to hydrate as much as they need to. All cells in the body are negatively affected by dehydration, and none are more sensitive than the brain. Water consumption of as much as two liters a day makes a huge difference in how you think and how you perform.

Abrupt weather changes at altitude trap many an unsuspecting visitor. Getting wet from light rain (or even sweat) just before the temperature plummets has led to hypothermia in athletes of all sports. Extra layers of clothing and accurate weather reporting are the best preparation for the arrival of sudden afternoon cold fronts.

Despite all these potential problems, most people excel at altitude. There is something about the clean air and majestic mountains that frees the spirit from the constraints of everyday life. The changes in lighting, the sunrises and sunsets, and the challenge of pushing oneself all merge into an unmatched beauty of spirit, perception, and physicality. It is important to go up there—to get high in the best possible way, and carry that elevated state home with you.