Newly published research has shown that hot tub therapy provides benefits for people with type 2 diabetes.

According to a December 2024 study published by scientists at the University of Portsmouth, England, hot tubs can improve insulin effectiveness and heart health and lower blood pressure.

The small-scale research involved immersing 14 participants with type 2 diabetes in 104°F water for an hour, eight to 10 times within a two-week period.

Results showed that participants experienced improved insulin sensitivity, meaning that their insulin worked better after repeated immersion.

Dr. Ant Shepherd, an author of the research from the University's School of Psychology, Sport and Health Sciences, said, “People with diabetes have high levels of sugar, which is what characterizes the disease. What we want to do as scientists is to lower those sugar levels.”

“There are ways in which we can do this, such as diet and exercise, or prescribing drugs,” Shepherd said. “But although these treatments are effective, there can be barriers, which means other treatments are urgently needed.

While research on hot water therapy is still limited, this study has clearly found that being immersed in a hot tub made the participants' bodies more sensitive to insulin.

“The pancreas is like a battery; you can only produce so much insulin and at some stage — particularly in those with type 2 diabetes — it will run out. If we can make people more insulin sensitive, producing less, it's far better for the pancreas long-term.”

As in previous studies, the current study also demonstrated that the hot tub treatments lowered blood pressure and allowed the heart to work easier, and the benefits extended beyond the immersion periods.

“The exposure to hot temperatures made the body work better, but not just while the participants were sitting in a hot tub — we also saw the heart having to work less hard days after they'd been immersed,” said Dr. Thomas James, the lead author of the study.

This is because when the body is exposed to heat, it adapts by lowering its resting temperature, which reduces the amount of energy burned. Less energy burned at rest means less oxygen is needed to be delivered around the body.

“This means the heart doesn't have to work as hard to keep the body supplied with enough oxygen,” Thomas said. “And when the heart is pumping less blood around the body, it also reduces the pressure inside our blood vessels. It's a bit like when you turn down the water flow from a hosepipe, the pressure inside the hose decreases.”

Further research is needed to fully grasp the benefits of hot tub therapy on people with type 2 diabetes, with more comprehensive research conducted on a larger participant group, but researchers are hopeful that their results will help people to manage their disease.

“We hope these findings could potentially extend to improved wellbeing, improved blood sugar control, and better heart health for individuals with the disease,” Thomas said.