It’s often hard to get out and get moving—to hit the gym or go running after a day of work and chores. Exercise isn’t always enjoyable, and the idea of a relaxing hot bath probably sounds better than a workout any time. A researcher in the UK has actually dedicated himself to comparing the benefits of a workout with a long soak in a hot tub or an hour in the sauna. “And the evidence, thus far, is promising,” writes Charles James Steward, a PhD candidate at UK's Coventry University in The Conversation.
“In a world where many of us are working nine-to-five office jobs and our daily tasks can be completed by a mere click of a button, it’s easy to see why the modernisation of societies have led to higher levels of sedentary behaviour. There is an urgent need to find alternative strategies to improve health that people are willing to follow,” Steward observes.
To find these alternatives, Steward's research involves looking into how hot baths and saunas affect the body, based on the fact that different cultures around the world have advocated heat therapy to improve health. From the Romans bath houses to the Japanese practice of onsen or hot spring bathing to the dry saunas of Nordic countries, heat therapy has been part of many cultures as a means to promote mental and physical well-being. There has also been scientific research that has linked regular bathing in a sauna or hot tub can to reduced risk of cardiovascular disease.
Steward and his fellow researchers at Coventry University compared the similarities and differences “between the physiological responses of exercise and heating”. They asked volunteers to spend the same amount of time bathing in a hot tub as they did on a moderately intense cycling session.
“While exercise is more adept at increasing energy expenditure, we have found comparable elevations in core body temperature and heart rate,” he writes. “The similarities also go beyond what you can physically feel. By doing ultrasound scans of the arteries, I also observe similar increases in blood flow.” Both exercise and heat therapy aid cardiovascular health as they have a similarly positive effect on blood vessel health, blood pressure and glucose levels.
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But this doesn’t mean you can stop working out and just soak in a warm water for a few hours a day. The research team also found that regular saunas or hot baths do not provide the other benefits that regular exercise does—strength training, increasing muscle mass and promoting fat loss. This is because you don’t expend much energy while sitting in a tub or a sauna, and long-term weight loss and overall fitness is dependent on burning more calories than you eat. However, for those who cannot exercise due to injuries or illnesses, heat therapy can provide some physical and mental health benefits.
“Using hot baths or saunas shouldn’t be considered as a substitute for exercise. But it can mimic some of the health benefits – and we think that when used in conjunction with exercise, it can give rise to greater health,” he concludes. The team will continue its studies into heat therapy and the beneficial effects on health.