• Take it easy for the first 24-48 hours. At 6,000 ft. 12 hrs may be enough. The effects of hypoxia (an oxygen deficiency) will make it difficult to exercise and can lead to Acute Mountain Sickness (AMS).
• Take frequent breaks when exercising because of the thin air.
• Sunlight is more intense at high altitude; use dark glasses/goggles, hats and sun block. There is 25% less protection from UV rays at Denver.
• Drink 6-8 glasses of water a day to avoid dehydration, which already occurs faster due to the marked dryness of the high mountain air, combined with the increased breathing rate from less oxygen. This is a major cause of altitude sickness.
  See Hydration under health.
• Avoid alcohol which is a diuretic causing dehydration because:
  1. The kidneys take time to filter out large quantities of water to break down the alcohol.
  2. It halts the production of the body's anti-diuretic hormone.
  Both result in more frequent urination and so speeding up the loss of fluid from your body.
  If you do drink alternate alcoholic drinks with non-alcoholic ones.
  See Alcohol under health.
• Some people also consider caffeine a diuretic, but it does not affect hormone's the way alcohol does. It weakens the detrusor muscles in the bladder, which provokes the need to urinate.
  See www.vanderbilt.edu/AnS/psychology/health_psychology/caffeine_sports.htm
• Weather changes VERY quickly at high altitude, so cary extra clothing.
• Carbohydrate is the preferred energy source at altitude. Carbohydrates replace depleted muscle glycogen stores, prevent protein from being used as energy, and require less oxygen for metabolism. Avoid high-fat foods such as cheeses, summer sausage, and jerky.
  Potassium is especially helpful to physiological maintenance at greater heights. So, eat foods such as broccoli, bananas, avocado, cantaloupe, celery, greens, bran, chocolate, granola, dates, dried fruit, potatoes, tomatoes.)
• Water boils at a lower temp (202° at Denver), so cooking will take longer.

Links:
Acute Mountain Sickness prevention.
High Altitude Tips
The High Altitude Medicine Guide
Human Biological Adaptability: Adapting to High Altitude
An Altitude Tutorial at the International Society for Mountain Medicine (ISMM)
Nutritional aspects of high-altitude exposure in women
Dangers of Alcohol at Mountain Cocktails.
Nutritional Advice for Military Operations in a High-Altitude Environment at U.S. Army Research Institute of Environmental Medicine