Can Sitting in a Sauna Help You Build Muscle?

Sitting in a sauna is relaxing after a tough workout. Plus, the heat that a sauna produces helps soothe your achy muscles. You might think that’s the only benefit you get from soaking up the intense warmth from a sauna – but there’s growing evidence that saunas have additional health benefits. In fact, most homes in Finland have a sauna because the residents believe in the health benefits a sauna offers. To them, the experience of resting in a sauna is almost sacred and an experience they take part in for the mental and physical health benefits it offers. Can Americans learn a lesson from the Finnish?

Here’s a benefit that may surprise you. Preliminary research shows that saunas may help with muscle building. Should you head for the sauna before or after a strength-training workout? Let’s look at how saunas, and possibly hot baths in lieu of a sauna, might aid muscle development if you train.

Impact on Growth Hormone

You often hear bodybuilders talk about growth hormone in the context of bodybuilding. Growth hormone is secreted by the anterior part of the pituitary gland in your brain. You release the greatest amount of growth hormone during the deepest stage of sleep. That’s one reason sleep is so important for healthy body composition. Your pituitary gland also churns out more growth hormone in response to resistance training and endurance training, especially when you increase exercise intensity.

What’s so special about growth hormone? It aids in muscle growth and helps with the preservation of bone mass. One way growth hormone stimulates muscle growth is by its impact on a hormone called IGF-1. This hormone is made by the liver and turns on muscle protein synthesis. That’s what you want if you’re trying to get stronger or build muscle size. Unfortunately, you produce less growth hormone as you age. This partially explains why people lose muscle and why it’s harder to build muscle later in life.

You might wonder what this has to do with saunas. A study dating back to 1986 showed that sitting in a dry sauna one hour twice daily for 7 days led to a four-fold increase in growth hormone release in women. It also stimulated growth hormone release in men. Since growth hormone, through IGF-1, aids in muscle protein synthesis, this works in your favor if you weight train. Remember, as we age, we naturally produce less growth hormone. Resistance training, combined with adequate sleep and sauna visits could boost your body’s growth hormone release.

Activation of Heat Shock Proteins

Sitting in a hot sauna places mild stress on your body as you’re exposing it to more heat than it’s accustomed to. In response, your body produces heat shock proteins. Other stressors such as infection, starvation, low levels of oxygen, toxins, and even exercise also trigger the production of heat shock proteins. Your body makes these proteins to help repair cellular damage that could occur in response to heat exposure.

In addition, these proteins activate your body’s internal antioxidant defense system. This, in turn, can stimulate muscle growth. In animals, heat shock protein enhances the growth of muscle tissue. Heat shock proteins also make your body, including your heart, more resistant to stress, partially by reducing oxidative damage. So, along with potentially boosting muscle growth, heat shock proteins offer an added layer of protection against stress-induced damage.

Improvements in Insulin Sensitivity

Insulin sensitivity is important for healthy body composition. When muscle cells are more sensitive to insulin, they take up amino acids and glucose more efficiently and don’t require as much insulin release. The muscle cells then use the amino acids to build new muscle tissue. Greater insulin sensitivity helps better deliver muscle-building amino acids into muscle cells. Plus, greater insulin sensitivity makes you more resistant to gaining body fat. When you DON’T have good insulin sensitivity, your pancreas has to produce more insulin. As insulin floods your bloodstream, fat cells can’t release fat stores as readily and you hang on to stored fat.

The good news is regular sauna sessions seem to improve insulin sensitivity. Not only is this important for muscle development, it helps with blood sugar control. If you have diabetes, sauna sessions may be beneficial. However, always consult with your doctor before using a sauna or taking a hot bath, especially if you have diabetes or heart disease.

Other Benefits of Sauna Sessions

Relaxing in a sauna may be good for the health of your heart as well. Studies show that heat enhances the release of nitric oxide from the inner walls of arteries. This improves blood vessel function, making the blood vessel more flexible and, in turn, lowering blood pressure.

What if You Don’t Have Access to a Sauna?

Not everyone has a sauna at home or has access to one, at least not in the United States. If you don’t, research suggests taking a hot bath may offer similar benefits. In fact, studies show that a very warm bath stimulates the release of heat shock proteins. Preliminary research also shows heat from a bath lowers blood glucose and burns significant calories in the process. According to one study, an hour in a hot bath (around 104 degrees F) expends around140 calories, equivalent to taking a 30-minute walk. As mentioned, talk to your doctor before cranking up the heat in your tub.

The Bottom Line

Whether you choose a hot bath or a sauna, keep your initial sessions short, only a few minutes. Gradually increase the amount of time you spend in a sauna over several weeks, until you’re able to tolerate 20 minutes or so. You might discover that you enjoy the experience as your body adapts to the heat. Don’t forget to drink more fluid if you stay in a warm environment for any length of time.

 

References:

Acta Physiol Scand. 1986 Nov;128(3):467-70.
Br J Pharmacol. 2008 Jun; 154(3): 557–568. Published online 2008 May 26. doi: 10.1038/bjp.2008.153.
Harvard Health Publications. “Growth hormone, athletic performance, and aging”
“Hyperthermic Conditioning for Hypertrophy, Endurance?” Rhonda Patrick, Ph.D.
Med Hypotheses. 2009 Jul;73(1):103-5. doi: 10.1016/j.mehy.2008.12.020. Epub 2009 Feb 8.
Wellness Mama. “The Benefits of Saunas (& the Risks)”
Indian Express. “Hot bath shares similar health benefits with exercise, says study”

 

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