It’s the middle of July and you’re already gazing at the mountains through your office window, looking forward to your winter skiing
vacation. You’ve saved, spent countless hours online, mapping out all of the details: flights, hotels, rental cars, lift tickets, equipment rentals, restaurants, what to do with the kids, etc. You finally arrive at Mount Nirvana, having just zoomed up from sea level to 8,000 feet in one day. And then it hits you. You spend the next three days in your hotel room trying to recover from the altitude, years of sedentary living and all of the drinks you had on the plane.
Anyone that’s spent any time outdoors can relate. Altitude does some pretty creepy things to the body. Regardless how good an athlete you are at sea level, your body rebels at altitude. That’s because your body is a finely tuned mechanism that is designed to operate under some fairly static conditions. As soon as you change one thing, like the amount of oxygen you breathe, the body responds by making some pretty radical adjustments in other areas.
Whether you live at sea level or at high altitude, all of us process oxygen in the same way. We have mouths and lungs that bring oxygen into the body and we have blood that transports this oxygen to our muscles and tissues. At sea level, your blood is approximately 97% saturated with oxygen. As you rise in altitude, the air becomes “thinner”, meaning that there is less oxygen taken in with each breath. At 12,000 feet above sea level, the blood is around 90% saturated. Climbers on Mt. Everest (29,000 feet above sea level) have blood that is only 42% saturated. At elevations over 1200 meters (approximately 4,000 feet), the body begins to respond to a decrease in oxygen by increasing the ventilation, or breathing rate; both at rest and during physical activity. In addition, the heart needs to work harder to accomplish the same amount of work, so the heart rate goes up as well. This is what is happening to you as you feel your heart pounding through your chest while you’re walking through the hotel lobby.
Within three to four days, your body has begun to acclimate to the altitude. Both your breathing and heart rates begin to return to normal, sea level rates. Given enough time, your body would completely adapt to living at altitude. Unfortunately, you only have a week of vacation, so you never fully adapt before it’s already time to leave.
By now, almost everyone who has watched professional bicycling has heard about blood doping. Blood doping is the illegal act of introducing more oxygen-carrying blood into the body to enhance physical performance. The object of blood doping is to increase the relative percentage of red blood cells (hematocrit). The more red blood cells, the more oxygen-carrying ability of the blood and consequently, better performance. While extraneous, intentional blood doping is banned in international sports, a natural form of doping occurs whenever you travel from sea level to altitude. The normal, sea level hematocrit is slightly less than 50% of your total blood volume. This can rise to as much as 60% after acclimation to high altitude, largely due to the secretion of a hormone called erythropoietin, or EPO.
While the number of your blood cells is increasing, the more liquid part of your blood called plasma, is decreasing. This results in your blood becoming “thicker”. When your blood becomes thicker, your heart has to pump significantly harder to circulate the less viscous blood around your body. For certain individuals, with high blood pressure or a history of heart disease, this can be a very dangerous and even life-threatening situation.
Many people that climb elevations too fast experience physical symptoms of high altitude sickness. While you may not experience the same altitude symptoms driving up from Denver as someone who’s scaling Mt. Everest, none the less, they can be very serious and may warrant medical attention.
Acute mountain sickness (AMS) can appear at relatively low altitudes; sometimes below 6,000 feet above sea level. Symptoms include headache, nausea, vomiting, decreased appetite, weariness and sleep disturbances. You may experience all or just some of these symptoms. AMS usually appears about 6-12 hours after arriving at high altitude. Just about the time you’re checking into your hotel room and ready to go out to dinner. Fortunately, AMS disappears within a few days. If not, the only way to treat it is to return to lower altitude.
A far more serious form of high altitude sickness is High Altitude Pulmonary Edema (HAPE). HAPE usually progresses from AMS and is associated with accumulated fluid in the pulmonary system (e.g. the lungs, alveoli, etc.). Symptoms include shortness of breath, fatigue, chest pain, an increase in resting heart rate, coughing and lips and extremities turning blue (cyanosis). HAPE can be fatal, so it requires immediate medical attention.
High Altitude Cerebral Edema (HACE) is another very serious form of altitude sickness that occurs when the rate of ascent occurs too quickly. Symptoms include severe headaches, fatigue, vomiting, nausea and changes in mental state. Fortunately, unless you are vacationing at the base camp of K2, you will never experience anything more serious than acute mountain sickness. And if you do, it usually doesn’t stay around for very long. Better yet, there are a number of things that you can do to prevent getting hit with an acute bout of altitude sickness.
Whenever possible, try to include some extra time in your trip for extended travel on the way to your high altitude destination. Some experts recommend rising no more than 1,000 feet per day. For people planning ski vacations in the Colorado Rockies, try spending a day in Denver, taking in the local sites and acclimating to the altitude. Denver sits at 5,280 feet above sea level; about half way up the elevation that you’ll be experiencing say at Vail, whose base elevation is at 8,150 feet above sea level. If you can’t afford to take that much time, try to plan your flight so that you arrive at the resort comparatively early in the day. Don’t ski the first day. Take it easy, unpack, walk around the base of the resort and enjoy the sights. It will probably be the last time you take time to do so, anyway.
Whether you are at sea level or at altitude, drink plenty of water. Current nutritional guidelines suggest drinking 8-10 glasses of water per day. Since few of us really do drink that much water, chances are you’ll be arriving at your vacation destination already dehydrated. And at higher elevations, you tend to lose more body water through normal respiration, because the air is much drier than at sea level. Physical activity exacerbates this condition.
You may also try eating a carbohydrate rich diet and/or try taking Acetazolamide (Diamox) several days before you leave for vacation to ward off unwanted high altitude sickness symptoms. While at your destination, reduce or lay off the alcoholic drinks. You should also limit the amount of coffee and other caffeinated drinks you imbibe; all are diuretics and can rob your body of precious water.
Acute mountain sickness is no fun and can ruin your outdoor plans. But with a little advanced preparation, you’ll be ready to enjoy your great outdoor vacation.