Off-mountain training for altitude climbing is different than training for other sports; you also need to account for inevitable muscle loss at altitude and acclimation for altitude.
At altitude a body finds it easier to eat muscle rather than food in the stomach because it takes less oxygen. In fact the level of muscular atrophy that occurs at altitude in 6 weeks with a strenuous climbing schedule equates to 8 weeks of total bed rest at sea level. On Aconcagua Bill lost 23lbs in 21 days (177lbs to 154lbs), on Rainier and Mt. McKinley combined he once again lost over 20lbs in 18 days (182lbs -162lbs) despite eating more than 4500 calories per day on the mountain. His body fat percentage was under 7% previous to both climbs. With Mt. Everest left Calgary at about 195lbs and 9% body fat and returned at 153lbs. His trainer’s challenge was to rebuild Bill after each major climb which typically takes a full 4 -8 weeks and then adding to that base in preparation for the next expedition.
Bill’s off mountain training for major expeditions is very intense with a focus on core, legs and endurance. For his current iceclimbing schedule the focus is the same but now includes extensive upper body work. His trainer, Wayne Johnson, with Full Body Fitness, aggressively pushes Bill during his work outs as altitude demands a higher heart rate. 160bpm is not unrealistic to maintain at altitude for hours especially considering that a resting heart rate at 20,000 ft for Bill is close to 130 (see level he is about 55). Maintaining 170bpm for an hour or two is not an unrealistic training session. Wayne’s sessions during Everest training were generally insane and he typically trained Bill for 6-10 hours per week and will get as high as 2.5 hours per day 5 days per week. Typically he wears 53-125lbs weight vests for all exercises. For sample training sessions – see the videos and training log for others.