It usually takes me 3 days to acclimate, but it is important that you have enough red blood cells! We are "recovering vegetarians" - but still prefer to eat salmon or vegetarian dishes. But we are traveling from sea level to the rockies for a 1000 mile bike tour in a few weeks. We are almost always on the very low side of normal for anemia, So we have been eating steak about two or 3 times a month - and it has helped our hematocrits rise to good solid upper mid range values. Your body can use the iron in red meat much better than the iron found in vitamins,vegetable,fish or poultry sources. Some people take a diuretic called Diamox to treat/prevent altitude sickness - you would get an rx from your doctor. It is important to heed your body though - altitude sickness can be very serious! Tokie