Book excerpt: Developed for Navy SEAL trainees to help them meet the rigorous demands of the Naval Special Warfare (NSW) community, this comprehensive guide covers all the basics of physical well being as well as advice for the specific challenges encountered in extreme conditions and mission-related activities. Topics covered include calculating energy expenditure; definitions, functions, and daily allowances of carbohydrates, fats, and protein; nutritional considerations for endurance and strength training activities; active recovery from injury; cardio-respiratory conditioning; appropriate gear for running and swimming for fitness; exercising in extreme and adverse weather; and more. Compiled by physicians and physiologists chosen for their knowledge of the NSW and SEAL community, this manual is a unique resource for anyone wanting to improve his or her health, strength, and endurance.