A reassuring recent study found that older people, even those with heart disease, can usually exercise safely at higher altitudes if they take it easy for a few days when they reach the higher destination until they adjust to the altitude. As a rule, at altitudes about 10,000 feet, one should not ascend more than 1,000 feet per day. At the sign of any symptoms, particularly headache, one should stop, and if they worsen, move down. Six to eight glasses of water or juice a day prevents dehydration. It is always wise to avoid alcohol when traveling or climbing to high altitudes.
Some medications are available for prevention of acute mountain sickness.
It may also be used to treat minor symptoms of acute mountain sickness but if they continue, the trekker should descend. Below Sea Level Travelers planning to descend rather than ascend must also take some precautions. In 1988, there were 66 scuba diving deaths, one-third due to air embolism caused by holding the breath while swimming up to the surface. Even tiny bubbles may do some harm over time. One study found that they appeared to increase risk for small brain lesions and degenerating spinal disks in amateur divers who dive frequently.