What does the phrase "climb high, sleep low" mean for acclimatization at altitude?

• A. Climb as high as possible and sleep wherever.
• B. Sleep at base camp every night regardless of climb.
• C. Only climb during daytime and rest at base.
• D. Climb to approximately 1000 feet a day and sleep at a lower altitude to acclimate.

Answer: (D)

Acclimatization at altitude works best when you expose yourself to higher elevation during the day but give your body time to recover at a lower altitude each night. The idea is to climb steadily—about a thousand feet in elevation per day—and sleep at a lower altitude to allow the body to adapt to the reduced oxygen. This nightly descent reduces overnight hypoxia, giving your lungs, blood, and brain a chance to adjust, which lowers the risk of acute mountain sickness and other altitude-related problems.

If you push too high too quickly, you don’t give your body enough time to adapt, which raises the risk of headaches, nausea, fatigue, and more serious issues. Sleeping at the base or resting only at the base camp every night doesn’t take advantage of the acclimatization process, while climbing during the day and staying at a much higher altitude overnight continuously ignores how the body needs a lower altitude to recover. The practice of climbing gradually and sleeping lower is the practical, safer approach to acclimatization.