Can’t Work Out? Try a Hot Bath

Researchers say a hot bath can help reduce inflammation and control blood sugar. But it’s not a substitute for exercise.
You likely think of a relaxing bubble bath as the antidote to a stressful day.
It certainly can be that.
But new research suggests a long, hot bath may be as helpful to you as a gentle workout session, too.
British researchers report that hot-water immersion — that is, a long sit in a hot-water bath — may help reduce inflammation and control blood sugar levels in much the same way exercise does.
This is especially helpful for people who are unable to exercise or meet the weekly physical activity recommendations.
However, before you turn on your faucet and drop in a dissolving bath bomb, you should understand the limitations of these findings.
Role of inflammation in health
Inflammation after exercise, such as sore muscles and redness, is to be expected.
During brief physical stress, levels of inflammatory markers rise.
These markers signal the production of another inflammatory chemical called interleukin.
After this initial increase in inflammation, your body produces an extended release of anti-inflammatory chemicals. These substances combat the high levels of inflammation caused by the exercise.
This is a natural, normal process: Brief inflammation is followed by prolonged anti-inflammation.
However, when the anti-inflammatory process isn’t robust enough, your body may be left with chronic, low-grade inflammation.
This type of inflammation isn’t healthy. In fact, it may contribute to a number of health conditions, including obesity and diabetes.
Exercise can combat the inflammation, but not everyone is able to exercise. Or they may not be able to exercise at levels adequate enough to reap the anti-inflammatory rewards.
In recent years, research has shown that raising body temperatures can also influence the body’s inflammatory response.
What’s more, research suggests this same spike in body temperature may increase the production of nitric oxide. This substance in your blood can help improve blood flow and transport glucose throughout your body.
What’s been unclear, however, is if exercise alternatives, such as sitting in a hot tub of water, can produce the same low-grade inflammation and healthy anti-inflammation responses.
What the researchers found
For this test, researchers recruited 10 overweight and sedentary men.
The participants were divided into two groups. Both groups sat in an 80°F (27°C) room for 15 minutes.
Then, the first group of volunteers participated in an immersion bath in 102°F (39°C) water up to their necks for one hour.
The second group sat in a room at ambient temperature for the same amount of time.
In 15-minute intervals, researchers took measurements of each participant’s blood pressure, heart rate, and core temperature.
Blood samples were taken before the tests, immediately after the test, and in a follow-up session two hours after the test.
The researchers took blood samples from each of the men at these points in the study so they could examine the markers for inflammation, blood sugar, and insulin levels.
Three days after the first test, the participants returned and reversed roles.
The single hot-water immersion session did produce some positive effects.
Namely, it caused the levels of interleukin (the inflammatory chemical) to rise and increased the level of nitric oxide in the blood.The rise in nitric oxide can cause blood vessels to relax, which can lower blood pressure. Nitric oxide is also thought to improve glucose intake by your body’s tissues.
For the final stage of the test, the participants returned to complete 10 hot-water immersion sessions in 14 days. The first five sessions were 45 minutes long. The final five were 60 minutes.
Blood samples taken after the two-week treatment period saw even greater results.
Fasting blood sugar and insulin levels were down, as were levels of low-grade inflammation.