According to new research, a hot bath could have effects that extend way beyond mental relaxation. According to the authors, regular hot baths might reduce inflammation and improve metabolism.
Over recent years, hot baths, saunas, and other so-called passive heating therapies have received growing attention from scientists.
Because hot baths are low cost and unlikely to cause significant side effects, understanding any benefits that a hot bath might have could be a quick win for medical science.
Recently, researchers set out to understand whether hot bath immersion could have an impact on metabolic disorders, such as diabetes.
In the most recent study, the researchers dug a little deeper into the mechanisms at work. They theorized that the influence of a hot bath over glucose metabolism might revolve around the inflammatory response.
There is some evidence that chronic, low-level inflammation increases insulin resistance. In other words, inflammation reduces a cell’s ability to respond to insulin, potentially contributing to the development of diabetes.
Conversely, exercise has been shown to reduce inflammation and improve insulin sensitivity — meaning that the body has better control over glucose levels.
Although doctors often recommend exercise to reduce the risk of developing metabolic disorders, not everyone can exercise — perhaps due to health conditions or physical capacity. It is, therefore, essential to find alternative ways to improve insulin sensitivity for these people.
Hot bath intervention
Each participant immersed themselves in a water bath set at 102°F (39°C) for 1 hour. Scientists took blood just before and after the bath, and then 2 hours later.
Also, the researchers charted the participants’ blood pressure, body temperature, and heart rate every 15 minutes.
Over the following 2 weeks, the participants had a further 10 hot water immersions.
The researchers found that a single hot water immersion caused a spike of interleukin — a marker of inflammation. Similarly, there was an increase in nitric oxide (NO) production.
The spike in NO is important because it causes blood vessels to relax, lowering blood pressure. NO also improves glucose intake into tissues, and scientists think it has anti-inflammatory properties.
As expected, the 2-week intervention saw a reduction in fasting blood sugar and inflammation. In the same way that exercise influences inflammation, the researchers saw an initial increase followed by a long-term decrease in inflammation.