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Why You Should Make Heat Therapy Part of Your Fitness Program

By Tom Nikkola, CSCS, CISSN, Pn1

Sitting is as bad as smoking. At least that’s what a lot of Facebook memes have said lately.

Usually, sitting is really bad for you. But if there were ever a great time to sit still, it’s while spending time in the sauna or steam room.

Heat therapy stimulates hormone production, helps rid the body of toxins, improves cardiovascular health, and speeds recovery and injury rehabilitation. We view heat therapy as a Nourish It strategy in the Core 3 system.

I’ll admit, even though I’ve worked out at a Life Time Fitness club since 2001, and had saunas and steam rooms readily available, it wasn’t until the past six months that I made an effort to include sauna sessions into my weekly routine. I didn’t realize how significant the benefits were until I delved into the research.

If more people knew how valuable heat therapy was, there would be lines waiting to get in the sauna or steam room at your fitness center.

I can see it now. Bouncers outside the door, letting one person in as another exits. Okay, maybe it won’t be that extreme.

Heat Stress

Brief, intermittent periods of extreme heat creates a stress response in the body. Depending on the heat and humidity, core temperature starts increases in 5-15 minutes.

As temperature rises, the body responds by rerouting blood flow, speeding heart rate, increasing blood vessel dilation and secreting a number of hormones.

Heat also stimulates heat-shock proteins, which play a role in organizing other proteins, and are thought to play a role in the growth of muscle tissue. They also support the immune system by identifying proteins from cells that don’t belong in the body.

The principal of “more is better” doesn’t apply to the sauna or steam room. The goal is to reach a point where the heat becomes uncomfortable, but not push it to a point where you reach the verge of passing out.

Once a threshold is hit, you can step out and get in a cold shower or pool. After cooling down, you can return to the sauna or steam room. You’ll respond faster the second or third time you enter the heat.

Again, the goal is to reach a point where the body senses a threat, NOT to see how long you can stay in before needing to ride home in an ambulance.

Heat and Hormones

Studies show growth hormone levels increase from two to five times normal levels. Growth hormone releasing hormone has been shown to rise to four times normal levels. [i]

Growth hormone aids in recovery of muscle, bone and even helps speed up recovery from injuries. It is also a powerful fat loss hormone.

Exercise also elevates growth hormone levels, and heat and exercise seem to act synergistically, elevating growth hormone more than either do alone.[ii]

Norepinephrine levels rise to two to four times normal levels. This isn’t surprising since norepinephrine is secreted during stressful events, and the high heat is perceived as a stress.

The effects of other hormones, such as cortisol, epinephrine, and thyroid are mixed. In some studies, they’ve increased, but in others, their levels have stayed the same. Testosterone levels appear to be unaffected.

The body perceives the heat as a stress, and hormones are secreted accordingly.

One word of caution: If you are recovering from adrenal fatigue or exhaustion, work up to longer durations slowly, and be sure to cool down quickly after to avoid excessive stress on your body.

Some hormones take up to 24 hours to return to normal.[iii]

Post-Workout and Injury Recovery

Heat therapy has benefits immediately following an injury or surgery, and during the rehab period when strength and muscle mass are rebuilt.

Injuries result in muscle damage, a strong immune response, and tissue breakdown.

Joints are immobilized immediately following the injury. Without movement, the muscles around the joints atrophy quickly.

The loss of lean mass can become noticeable in as little as a week. During this period, supplement, lifestyle and nutrition strategies should focus on reducing the rate of protein breakdown in muscle.

Evidence suggests intermittent exposure to heat stress reduces the rate of atrophy, or muscle catabolism. It also reduces the buildup of free radicals, which are typically increased in immobilized muscle.[iv],[v]

Sauna and steam rooms may also aid in the recovery process, once rehabilitation and strengthening begin. During the rehab process, strength and muscle mass are slowly regained.

Even though the actual loads on the muscle are relatively low, compared to what it’s done in the past, there is an increased rate of oxidation compared to uninjured muscles. Lifting a five pound dumbbell during rehab may create more oxidation than using 50 pounds with a fully recovered muscle on the same exercise.

The high rates of oxidation may compromise the recovery rates. The oxidation can cause damage to cell membranes, and uses up much of the body’s glutathione stores.

Heat therapy reduces the rates of oxidation and increases the rate of muscle tissue regrowth.[vi] I thought it was pretty cool to see that the referenced study was funded by the National Football League Players Association. No doubt pro football players would benefit from regular sauna or steam sessions.

With heat therapy’s ability to enhance muscle growth and limit oxidation, it should also enhance the recovery process from exercise for healthy individuals. Combining heat therapy and the use of essential amino acids and curcumin is a great way to speed recovery and support growth of muscle.

Heat therapy is also recommended for others with chronic pain, such as arthritis or other degenerative diseases.[vii]

Heat and Detoxification

The sauna is well-known for its ability to support detoxification. The sauna is superior to the steam room for detoxification because people sweat more, due to the lower humidity and higher temperature.

A large amount of everyday toxins are released through sweat. This can be especially beneficial for those losing large amounts of weight. The body stores toxins in fat cells as a way to isolate them from the rest of the body’s cells.

As someone loses body fat, the toxins are released as well. Sweating helps to remove them from the body. To maximize the removal of toxins, periodically wipe off your sweat with a towel while you’re in the sauna.

I was fascinated by one particular study on this topic.

About half of Utah police officers that were involved in methamphetamine drug busts developed varying levels of symptoms from exposure to the drug and its byproducts. Some symptoms were debilitating.

Following a nutrition, aerobic exercise and sauna therapy program, they saw a significant reduction in symptoms form the methamphetamine exposure.

Just don’t spend time in the sauna or steam room while drinking alcohol. You won’t reduce the effects of alcohol. If anything you’ll amplify them with your elevated heart rate and reduced hydration.

I also wouldn’t recommend heat therapy the morning after drinking too much. Part of the reason for a hangover is dehydration. You could make things worse by sitting in the heat.

To fully appreciate the detoxifying effects of the sauna, consider pairing it up with a high-quality detoxification program.

Other Sauna Benefits

Sauna sessions increase production of white blood cells, enhancing immune function. In fact, regular sauna sessions have been shown to reduce the chance of catching a cold.

Sauna sessions have also been shown to help those with respiratory dysfunctions, heart disease, and for preventing infections.[viii],[ix],[x]

Even though the heat makes the heart work harder, there is a lot of evidence to show it is beneficial for those with cardiovascular disease.

Animal research suggests heat therapy improves insulin sensitivity.[xi] Insulin resistance affects a significant portion of the population, and can lead to unwanted fat gain, eventual development of diabetes and is related to future cognitive problems. Will the heat therapy get you leaner than diet and exercise? Of course not, but it can help speed the results of a good nutrition and exercise program.

Your body will adapt to the heat over time, making longer durations more tolerable.[xii] You may need to start with just five minutes and add a minute each week until you’re able to tolerate 2-3 entrances of 15, separated by cool down periods.

Cooling Down

Cooling down quickly is as important as the heat exposure. As a kid from Northern Minnesota, I tried sitting in a lakeside sauna and cooling off by jumping into a hole in ice on lake. Fortunately, the cool down doesn’t have to be that extreme.

To speed the cool down period, take a cold shower or bath. If your body remains overheated, intravascular volume can decrease and hematocrit levels can increase.[xiii]

The low intravascular volume and elevated hematocrit makes the blood more thick and difficult to pump through the vessels. Fatigue is a common symptom of high hematocrit levels. Other symptoms include chest or joint pain, bruising and bloody stool, although these symptoms typically occur from chronically elevated hematocrit.[xiv]

Also, without cooling down quickly, cortisol levels may continue to rise and individuals may feel fatigued for much of the day afterwards. If you feel overly tired following heat therapy, try cooling off faster with a colder shower. You should feel refreshed, not worn out from the sauna.

Sauna vs. Steam Room

The sauna has been used in Finland for over 2000 years. The temperature is kept at about 80°C (176°F) to 100°C (212°C). The extreme temperature is tolerable because the humidity is kept very low.

The steam room, also known as a Russian Banya, is much more humid and has a lower temperature. The steam room is usually 40C (104°F) to 70°C (158°F). Because of its high humidity, most people cannot tolerate being in the steam room as long as they can the sauna.

Sessions in either include two to three entrances of 5-15 minutes, with cooling-off periods between each entrance. The average person loses about 0.5 liter of water in a sauna session, but sweat loss in the steam room is usually less.[xv]

The differences in temperature and humidity do create some differences in effects in the body.

With the low humidity level, the sauna allows for a greater amount of sweating. This is why people can normally stay in the sauna longer. Because they can sweat more, they’re able to cool themselves better than they could at higher humilities.

Even though the temperature is higher in the sauna, the humidity in the steam room causes a faster rise in core body temperature. The high level of humidity in the steam room does not allow for efficient perspiration. Sweat cannot evaporate because of the high humidity.

The sauna or steam room should both enhance recovery, support immune function and provide cardiovascular benefits. These changes occur as a result of the body becoming overheated. People often reach a threshold faster in the steam room, where the humidity makes it difficult to cool one’s self.

For those seeking relaxation and detoxification, the sauna is probably a better option, as it allows for more sweating, which supports detoxification, and is more tolerable, which helps with relaxation.

Either one – the sauna or the steam room – would be a wise addition to a health and fitness program. Work it into your schedule two to three times per week for two months and see if you notice a difference.

Thanks for reading. If you learned something valuable, please be sure to share this article on your favorite social media network.


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[i] Hannuksela ML, Ellahham S. Benefits and Risks of Sauna Bathing. Am J Med. 2001;110:118-126

[ii] Ftaiti F, Jemni M, Kacem A, Zaouali MA, Tanbka Z, et al. Effect of hyperthermia and physical activity on circulating growth hormone. Appl Physiol Nutr Metab. 2008;33(5):880-887

[iii] Pilch W, Szygula Z, Klimek AT, Palka T, Cison T, et al. Changes in the lippid profile of blood serum in women taking sauna baths of various duration. Int J Occup Med Environ Health. 2010;23(2):167-174

[iv] Naito H, Powers SK, Demirel HA, Sugiura T, Dodd SL, Aoki J. Heat stress attenuates skeletal muscle atrophy in hindlimb-unweighted rats. J Appl Physiol 88: 359–363, 2000.

[v] Selsby JT, Dodd SL. Heat treatment reduces oxidative stress and protects muscle mass during immobilization. Am J Physiol Regul Integr Comp Physiol 289: R134–R139, 2005.

[vi] Selsby JT, Rother S, Tsuda S, Prachas O, Quindry J, Dodd SL. Intermittent hyperthermia enhances skeletal muscle regrowth and attenuates oxidative damage following reloading. J Appl Physiol. 2007;102:1702-1707

[vii] Masuda A, Koga Y, Hattanmaru M, Minagoe S, Tei Ch. The effects of repeated thermal therapy for patients with chronic pain. Psychother Psychosom. 2005;75:288-294

[viii] Laitinen LA, Lindqvist A, Heino M. Lungs and ventilation in sauna. Ann Clin Res. 1988;20:244-248

[ix] Saadat H, Sadeghi R, Motamedi MR, Namazi MH, Safi M, et al. Potential Role of Thermal Therapy as an Adjunct Treatment in Congestive Heart Failure. J Teh Univ Heart Ctr. 2009;3:149-158

[x] Ernst E, Pecho E, Wirz P, Saradeth T. Regular sauna bathing and the incidence of common colds. Ann Med. 1990;22:225-227

[xi] Kokura S, Adachi S, Manabe E, Mizushima K, Hattori T, et al. Int J Hyperthermia. 2007;23(3):259-265

[xii] Magalhães FD, Amorim FT, Freitas Passos RL, Fonseca MA, Moreira Oliveira KP, et al. Heat and exercise acclimation increases intracellular levels of Hsp72 and inhibits exercise-induced increase in intracellular and plasma Hsp72 in humans. Cell Stress Chaperones 2010;15:885–895.

[xiii] Blum N, Blum A. Beneficial effects of sauna bathing for heart failure patients. Exp Clin Cardiol. 2007;12(1):29-32

[xiv] Polycythemia (High Red Blood Cell Count). Online article. Retrieved Sept 24, 2014.

[xv] Pilch W, Szygula, Z Palka T, Pilch P, Cison T, et al. Comparison of physiological reactions and physiological strain in healthy men under heat stress in dry and steam heat saunas. Biol Sport. 2014;31:145-149

The posts on this blog are not intended to suggest or recommend the diagnosis, treatment, cure, or prevention of any disease, nor to substitute for medical treatment, nor to be an alternative to medical advice. The use of the suggestions and recommendations on this blog post is at the choice and risk of the reader.
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