Comparing the effects of a 7-week repeated sprint training in hypoxia vs. heat in males and females.

Plain-language summary

This study compared two ways of making sprint training harder: doing it in thin air, and doing it in the heat. Healthy men and women trained twice a week for seven weeks, sprinting either in low oxygen (equivalent to moderate altitude), in a hot room at 30 degrees Celsius and 60% humidity, or in ordinary cool conditions as a control. Everyone was then tested in normal cool air, so the question was whether the harder training environment carried over. It did. The altitude group managed 6 more sprints than the control group before exhaustion, and the heat group 4 more, with no reliable difference between the two methods. Aerobic and anaerobic capacity did not separate the groups. A hint that men gained more from the altitude condition than women did not reach statistical significance, and with roughly a dozen people per group the study is too small to settle that question either way.

Key findings

• Sprinting in low oxygen produced 6 more repeated sprints before exhaustion than control training.
• Sprinting in the heat produced 4 more sprints than control training.
• Low oxygen and heat did not differ reliably from each other.
• Aerobic and anaerobic capacity showed no difference between the training conditions.
• A possible sex difference favouring low oxygen in men did not reach statistical significance.