Gard, 54, a five-time finisher of the Western States 100-Mile Endurance Run, has battled the condition for years. In fact, the effects of altitude sickness forced him to drop out of the famed event a few years ago.
"You get to the point where you just say, 'Oh, no, here it comes,'" Gard said. "You think you've prepared, you really do. There's some things that help, but you never know. You just have to be aware of it."
Triggered by oxygen deficiency in rarefied air, altitude sickness most often results in symptoms similar to a hangover headache, poor appetite and nausea.
Moderate cases can also include vomiting, shortness of breath while at rest, a raspy cough and coordination difficulties. More severe cases include disorientation, severe physical weakness and a persistent wet cough.
Extreme cases can also result in conditions defined with the acronyms H.A.P.E. (high-altitude pulmonary edema) or H.A.C.E. (high-altitude cerebral edema). In rare instances, high altitude sickness has even been fatal.
Fortunately, for runners or hikers heading toward the mountains as the weather gets warmer or for winter athletes, prevention is the key.
At most popular winter and summer mountain resorts, medical personnel treat a steady, year-round number of altitude sickness cases. Many resorts offer brochures or fliers about the condition.
"It can be almost anybody, even the best athlete," said Dr. Bill Blevins of the Mogul Medical Clinic at Taos Ski Valley. "Sometimes, an entire family will come into the clinic. They're looking forward to their vacation, but it's been ruined on the first day because they haven't helped themselves by taking precautionary measures. The best help for them is to drink plenty of fluids, to get to a lower elevation and relax."
While symptoms of mild altitude sickness can occur at elevations as low as 5,000 feet, it's particularly prevalent above 7,000 feet. At elevations above 8,000 feet, chances of acquiring altitude sickness symptoms increase by 15 percent.
Mountain recreation enthusiasts should also remember that being physically fit has no bearing on one's ability to acclimate to altitude.
"I remember leaving Robinson Flat (mile 30) at Western States one year and feeling all the symptoms headache, nausea, lightheadedness ," Gard recalled. "It's like the symptoms people get with exercise-induced asthma."
Last summer, during an off-year from 100-mile running, Gard opted to compete in the Leadville 100-mile mountain bike ride.
Well aware of his susceptibility to altitude sickness, his physician prescribed Proventil, an inhaler Gard used a half-dozen times during the race.
"It helped," Gard said. "But altitude sickness is something that's different for everyone. High elevations don't bother some people too much, but others are very susceptible to altitude sickness.
"There's all kinds of things people do. They get to an event a week early and train at altitude to get acclimated and still have problems. Other athletes get to the event the night before, don't worry about a thing and they don't have any problems. It's just best to experiment and see if you're susceptible."
Blevins advises high-altitude visitors and athletes to follow the following preventative guidelines:
- Sleep a night or two at a lower elevation en route to your designation. A gradual increase in elevation will help the body acclimatize.
- Take it easy on the first day on higher-elevation trips. Many exercise enthusiasts can't resist overdoing the first day of a trip, only to ruin the rest of their stay. Stop early when you start to feel fatigue or any prolonged breathlessness.
- Eat a high-carbohydrate diet. Increase your intake of carbohydrates (pasta, rice, potatoes, bread) to 70 percent of your total calories. Of course, this also means decreasing your fat intake.
- Avoid alcohol, tranquilizers and sleeping pills. These substances decrease the body's ability to adjustment to higher elevations.
- Drink an increased amount of fluids. Keeping hydrated helps prevent the onset of other conditions.