However, tea and coffee have a diuretic effect and promote fluid loss. In addition, excess caffeine can interfere with sleep that is already disrupted at altitude. Cocoa is a good warming beverage since it is low in caffeine and contains needed carbohydrate. Other beverage suggestions are hot cider or apple juice, hot Jell-O, or instant soups. An exception to the limitation of caffeine is when treating the incapacitating high-altitude headache.
Many climbers successfully use a double strength mug of coffee to relieve the headache.
Monitor the color and volume of soldiers' urine to check for dehydration. If urine is dark yellow or brown or less than normal, the soldier is probably dehydrated. Military rations however, already provide more than enough vitamins and minerals so supplementation isn't necessary. Most of the weight loss commonly seen at altitude is not inevitable but is due to the reduced calorie intake. Weight loss can be prevented or slowed down by keeping calorie intake up.