Exercise is not achievable by all. Researchers from the United Kingdom sought to understand if passive body heating can achieve similar benefits and reduce inflammation.
Exercise is a great practice for physical well-being. It increases strength, improves metabolism, and promotes beneficial, internal chemical changes. It also helps regulate blood sugar levels and low-grade inflammation, which is part of the immune response. This is important because chronic inflammation puts people at risk for insulin resistance or pre-diabetes. However, despite the benefits of exercise, making it a habit is tough. Those who would most benefit from exercise are often the ones who have conditions that make exercising difficult. Overweight and diabetic patients, for example, are sometimes unable to exercise.
Passive heating could have similar benefits to exercise
Luckily, similar benefits have been shown with passive heating. Increased body temperature can improve metabolism, blood circulation, mental health, weight loss, and regulation of the inflammatory response. Previous research has also linked higher body temperature with nitric oxide production. This substance helps blood sugar be carried more efficiently throughout the body.
Researchers from the United Kingdom studied the viability of this alternative solution to exercise. Using hot water baths, they assessed levels of exercise-associated chemical markers in the blood. Their findings were published in the Journal of Applied Physiology this November 2018.
A group of inactive, overweight men volunteered to participate in this study. They were seated in a 27°C room for 15 minutes before being split into two groups. One group was immersed in a 39°C water bath for one hour while the other remained in the room. After three days, the groups switched such that both groups experience both the hot water bath and the ambient temperature room. Their blood pressure, heart rate, and body temperature were measured every fifteen minutes in both settings. Blood samples were drawn before, immediately after, and two hours after each session.
Hot water baths lowered blood sugar levels, insulin levels, and inflammation
The research team found that even one hour-long hot water bath increased nitric oxide production and levels of IL-6, a protein in the blood that is an indicator of the inflammation. Two weeks of daily hot water baths showed lowered blood sugar levels after fasting (i.e. sleeping), insulin levels, and healthier low-grade inflammation at rest. The hot water intervention in this study thus improves metabolism and inflammation.
Hot water bath treatments can be difficult and impractical
Despite these results, the ability to use hot water baths daily is questioned. The study subjects expressed discomfort with the level and duration of heat they were exposed to. The method of treatment may be difficult and impractical for regular use. Nonetheless, this study presents an alternative method to improve metabolism. But how exactly will researchers amend the process to make it more feasible? We will have to see in the future.
Written by Amrita Jaiprakash, MSc
Reference: Hoekstra et al. The acute and chronic effects of hot water immersion on inflammation and metabolism in sedentary, overweight adults. Journal of Applied Physiology. 2018. doi: 10.1152/japplphysiol.00407.2018