Whether you’re planning on ascending high into the Alps or Rockies, or just want more power for crushing your buddies in sea-level criteriums and road races, breathing in the thin air of high elevation may help you improve your performance. Cycling performance is largely a function of oxygen uptake, delivery, and utilization by the body; and altitude training, whether by traveling or sleeping in a tent, may help you bring more precious oxygen to your working muscles.

The Physiology of Altitude