Study Finds Distance Runners Can Increase Time to Exhaustion by 32% With This Post-Workout Recovery Hack

Athletes will go to extreme lengths to boost performance. Powerlifters devour thousands of calories for a dirty bulk to hit their weight class for the next meet. Cyclists deprive themselves of caffeine, only to load up with a massive dose right before a race for a performance boost. Now, distance runners are jumping in with their own surprising tactic: using saunas to improve their time to exhaustion, all to maintain—or even surpass—their race times.

In a study published in the Journal of Science and Medicine in Sport, researchers followed six male distance runners over a three-week period. During this time, the runners underwent three weeks of post-training sauna sessions and three weeks of control training, with a three-week washout period.

During the sauna phase, the runners sat in a humid sauna at 89.9°C for 31 minutes after each training session, averaging around 12.7 sessions. Before and after each sauna session, the participants completed a treadmill run for about 15 minutes or until exhaustion, at their current best 5k race pace. They also measured blood markers like plasma and red-cell volume.

The researchers concluded that sauna use increased the time to exhaustion by 32%, which corresponds to a 1.9% improvement in endurance. Plasma and red-cell volume also increased by 7.1% (5.6-8.7%) and 3.5% (-0.8% to 8.1%). 

Related: Want to Build Strength Fast? This Science-Backed Shortcut Might Shock You

Researchers believe that the increased blood volume that developed over the three weeks of post-exercise sauna bathing was responsible for the significantly enhanced endurance performance.

In 2020, a study published in the European Journal of Applied Physiology confirmed the same. In this study, researchers followed 20 trained middle-distance runners. The runners were split into two groups: one group who continued their normal training routine and another who added sauna sessions at around 101–108°C, 5–10% humidity post-workout. The sauna group continued their sauna sessions for about 28 minutes, three times a week, for three weeks.

Before and after the training period, all participants completed several tests, including one to measure their heat tolerance during a run, a VO2max test to measure aerobic capacity, and a lactate threshold test. 

At the end of the study, researchers discovered that not only did the sauna sessions improve the athletes' heat tolerance and lactate threshold, but also improved their VO₂ max by 0.27 L/min. 

The bottom line? Sauna sessions do more than rev your metabolism and support heart health—they might also help you hold your pace longer when it counts most on race day.