Dietary Supplements Could Protect the Body During Hot-weather Workouts

Findings from multiple studies suggest plant compounds, probiotics support gut health and performance

Minneapolis—Certain dietary supplements may help the body better tolerate exercise in the heat. Researchers will present findings from multiple studies at the 2026 American Physiology Summit in Minneapolis. The Summit is the flagship annual meeting of the American Physiological Society (APS).

Exercising in the heat puts a significant amount of stress on the body. As temperatures rise, blood is redirected away from the digestive system to help cool the body. Reduced blood flow weakens the gut’s protective barrier and allows toxic bacteria to leak into the bloodstream (leaky gut). This process can trigger inflammation and contribute to heat-related illness.

Dietary supplements, including plant compounds, vitamins, minerals and probiotics, are widely used by athletes and physically active people to support health and performance. Some supplements are thought to play a role in inflammation and hydration levels, and gut health, which may contribute to how the body responds to physical stressors like intense exercise and heat.

Plant-Based Aids for Heat Stress
In a series of treadmill studies conducted in hot environments, researchers explored the physiological effects of berberine, curcumin and New Zealand blackcurrant.

• All three supplements reduced the rise in body temperature during exercise.
• Berberine and curcumin reduce the rise in heart rate during exercise by three to eight beats per minute.
• Berberine significantly reduced how hard the exercise felt (perceived effort and generalized discomfort).
• Curcumin and blackcurrant improved blood markers of gastrointestinal barrier function and reduced blood markers of inflammation.

These findings suggest that each of these compounds has merit, and “the combination of these dietary supplements should be evaluated for potential performance benefits in a controlled laboratory environment,” said Matthew Kuennen, PhD, corresponding author of the research review.

Probiotics and Exercise Recovery
A separate study examined whether probiotic supplements might provide similar protection. Recreational runners took a two-strain probiotic supplement (HN019^TM and HN001^TM) widely available over the counter in the U.S. for four to six weeks before completing treadmill running trials in a hot environment. Although the supplement did not increase the distance participants ran, it improved several markers associated with performance and recovery, including lower heart rates, fewer gastrointestinal symptoms such as bloating and stomach discomfort, and reduced markers of leaky gut and inflammation.

“Very intense or prolonged exercise in other conditions [besides heat] can cause similar physiological stress, so taking the probiotics in the weeks before and throughout high-load periods could be beneficial,” said Toby Mündel, PhD, corresponding author of the study.

Together, these findings highlight the growing recognition that the gut plays an important role in how the body responds to heat stress during exercise. While more research is needed, specific supplements, from plant compounds to probiotics, may help athletes and others exercising in hot conditions cope with heat-related stress.

NOTE TO JOURNALISTS: The American Physiology Summit will be held April 23–26, 2026, in Minneapolis. To schedule an interview with the researchers, conference organizers or presenters, or to request the abstracts “Integrated Effects of Berberine, Curcumin and New Zealand Blackcurrant on Physiological, Perceptual and Gastrointestinal Responses During Exercise Heat Stress” and “Two-strain Probiotic Supplementation Ameliorates Physiological Responses to Running in the Heat,” contact APS Media Relations or call 301.634.7314. Find more highlights from the meeting in our Newsroom.  

Physiology reveals how life works—from cells to body systems—and drives the scientific discoveries that transform health and save lives. It provides the foundation every medical advancement depends on. The American Physiological Society champions physiology—the science life depends on. It connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The Society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work.