Fig. 1.

Schematic illustration of the experimental protocol, with unweighted squats followed by a 45-min preoxygenation at 8200 ft (a; hypobaric condition; H) or at sea level (b; normobaric condition; N), and subsequently by a 60-min exposure to a simulated altitude of 28,000 ft, during which the JM was laying horizontally except for at minute 45 when he stood up and performed 10 weighted squats