Also, pick up some Gingko pills on line or at a store like Whole Foods, and take at least 120 mg per day (typically 2 pills) several days before arriving at elevation. Take two or three per day while hunting as well. This will help your red blood cells absorb more oxygen. They work, as a friend of mine from NY who has hunted at 9,000-10,000 ft for several years and prepared by taking these pills about two weeks prior to arrival, will attest. If you look at ingredients in Wilderness Athlete and Mtn. Ops, main ingredient is Gingko Biloba. A whole lot cheaper to simply buy the pills on line or in store.Great stuff here guys. Appreciate the insight!