SOME LIKE IT HOT: Science of the Sauna

We all complain about the hot summer swelter, but spending time in the heat can actually be beneficial for your health! Recent studies show that regular sauna use boosts your immune response (1,5), promotes cardiovascular and musculoskeletal health (2, 3), and can even help treat psychological disorders such as depression (4). 

          Sauna bathing is a special form of heat exposure that involves spending a short period of time, about 20-60 minutes, in exceptionally high environmental temperatures (4). The sauna itself is a wood-paneled room that is heated to 70-100^oC (158-212 ^oF).  Regular heat exposure at these temperatures, known as hyperthermic conditioning, can actually produce some of the same physical benefits as regular exercise and can even be used as a way to train your body to withstand the stress of everyday life. 

In the sauna you can achieve similar physiological responses you incur during exercise:

1. Sweating

2. Rapid breathing

3. Increased heart rate

4. Dilated blood vessels

At the same time, your core temperature is increased and your body responds to these changes by generating heat shock proteins. These proteins are made in response to physical stress in order to repair damaged proteins and to signal for enhanced cell growth and natural growth hormone release (5, 6). These protective proteins and increased blood flow allow injuries to heal faster, prevent future injury (8, 9, 10, 11), and even treat chronic pain (10). Other benefits include increased muscle hypertrophy, protein synthesis, and improved insulin sensitivity (12, 13). Keep in mind there are some risks of sauna use, such as dehydration and dizziness. You may want to check with your doctor if you have cardiovascular abnormalities since heat is form of physical stress (14). 

There are also documented benefits of sauna use for cardiovascular health, and may be used as a potential hypertension treatment (3, 4, 15).  If you have the chance to give the sauna a try, at the very least you could get a relaxing break out of it!

For more details on how hyperthermic conditioning can impact your physiology check out the science as seen by Dr. Rhonda Patrick at https://foundmyfitness.com/ .

References

1.     Turturici, G., Geraci, F., Candela, M. E., Giudice, G., Gonzalez, F., & Sconzo, G. (2008). Hsp70 localizes differently from chaperone Hsc70 in mouse mesoangioblasts under physiological growth conditions. Journal of molecular histology, 39(6), 571-578.

2.     Iguchi, M., Littmann, A. E., Chang, S.-H., Wester, L. A., Knipper, J. S., & Shields, R. K. (2012). Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans. Journal of Athletic Training, 47(2), 184–190.

3.     Crinnion, W. J. (2011). Sauna as a valuable clinical tool for cardiovascular, autoimmune, toxicant-induced and other chronic health problems. Alternative medicine review: a journal of clinical therapeutic, 16(3), 215-225.

4.     Kukkonen-Harjula, K., & Kauppinen, K. (2006). Health effects and risks of sauna bathing. International journal of circumpolar health, 65(3).

5.     Schlesinger, M. J. (1990). Heat shock proteins. J Biol Chem, 265(21), 12111-12114.

6.     Hannuksela, M. L., & Ellahham, S. (2001). Benefits and risks of sauna bathing.The American journal of medicine, 110(2), 118-126.

7.     Selsby, J. T., Rother, S., Tsuda, S., Pracash, O., Quindry, J., & Dodd, S. L. (2007). Intermittent hyperthermia enhances skeletal muscle regrowth and attenuates oxidative damage following reloading. Journal of Applied Physiology,102(4), 1702-1707.

8.     Scoon, G. S., Hopkins, W. G., Mayhew, S., & Cotter, J. D. (2007). Effect of post-exercise sauna bathing on the endurance performance of competitive male runners. Journal of Science and Medicine in Sport, 10(4), 259-262.

9.     Naito, H., Powers, S. K., Demirel, H. A., Sugiura, T., Dodd, S. L., & Aoki, J. (2000). Heat stress attenuates skeletal muscle atrophy in hindlimb-unweighted rats. Journal of Applied Physiology, 88(1), 359-363.

10.  Gore, J. Discover Saunas Super Healing Powers For Your Back Pain, Herniated Disc Or Sciatica. Obtained Sept. 23, 2015 from <http://strongerfitteryou.com/discover-saunas-super-healing-powers-pain-herniated-disc-sciatica/>

11.  Asea, A. A., Almasoud, N. N., Krishnan, S., & Kaur, P. (2015). Heat Shock Protein-Based Therapies. Heat Shock Proteins.

12.  Kokura, S., Adachi, S., Manabe, E., Mizushima, K., Hattori, T., Okuda, T., ... & Yoshikawa, T. (2007). Whole body hyperthermia improves obesity-induced insulin resistance in diabetic mice. International journal of hyperthermia, 23(3), 259-265.

13.  Carro, E., Trejo, J. L., Núñez, A., & Torres-Aleman, I. (2003). Brain repair and neuroprotection by serum insulin-like growth factor I. Molecular neurobiology,27(2), 153-162.

14.  Laukkanen, T., Khan, H., Zaccardi, F., & Laukkanen, J. A. (2015). Association between sauna bathing and fatal cardiovascular and all-cause mortality events.JAMA internal medicine, 175(4), 542-548.

15.  Vuori, I. (1987). Sauna bather's circulation. Annals of clinical research, 20(4), 249-256.