Sauna. Friend or foe for the athlete?

Jackson Peos PhD (c) Clinical & Sports Nutrition

In recent times, athletes from a variety of sporting backgrounds have engaged in the use of sauna, seeking a recovery edge from hard training and intense competition. Going beyond the competitive athlete demographic, sauna has been welcomed with open arms across the general “fitness” population trying to look a bit better naked, to the point where it is now not uncommon to find a sauna facility within a commercial gym or training centre.

The claims of sauna use are vast, including but not limited to, injury prevention, recovery enhancement, increased flexibility, improving anaerobic capacity, removing “toxins” and lactic acid build up, improving circulation, fat loss, and stress relief.

Those purported benefits could yield substantial value for any athlete, and thus it is no surprise that sauna has been so readily adopted not just in athletes, but in the broader fitness community. Before you start running off to your nearest sauna in your flip-flops and budgie smugglers, it’s important to remember that any extraordinary claim or supposed “cure-all” technique, must be justified with ample evidence. This piece was written to provide a brief review on the current literature surrounding sauna, as well as highlight a recent scientific study published late last year.

Our most recent systematic review

The sauna trend is no doubt capitalising on the public thirst for novel (perceived as advanced) strategies to enhance health, wellness, and aesthetic appearance. As such, saunas are offered in not just gyms, but health spas, massage clinics, and beauty salons. According to the latest systematic review, such facilities will promote sauna therapy as a means to “detox, increase metabolism, weight loss, antiaging, stress management, and pain reduction”. Are such claims supported by the research? This systematic review suggests no, stating that rigorous medical evidence to support these claims is scant and incomplete. 

Don’t slam the sauna door just yet. The authors do however propose that sauna may induce some other physiological benefits, namely increased nitric oxide production, activation of heat shock proteins, enhanced excretion of toxicants through increased sweating, and some immune and hormonal pathway alterations. However, it is important to note that these are acute changes occurring within the body – sometimes at a cellular level – and that does not necessarily mean that these changes will translate significantly to an athlete on a practical or meaningful level. For example, although sauna may increase nitric oxide production, we are still unsure whether this would translate to benefits in exercise performance or recovery for the athlete. In fact, the authors state that the aforementioned potential health benefits of sauna are likely most applicable for those with pre-existing cardiovascular-related and rheumatological disease. At this stage, the only consistent positive benefits for athletes reported in controlled studies are a subjective increase in quality of life, and improved skin moisture barrier properties.

The new study that has heated things up (pun intended)

There was a new study published in December 2019 that shined some infrared light (can’t stop these puns) on the potential utility of sauna for athletes, particularly with regards to recovery. Based at the Institute of Sports and Preventative Medicine in Germany, the researchers set out to determine the effects of sauna after an intense training session of swimming.

20 competitive swimmers and triathletes with a minimum of 2 years competing at least at the National level were recruited for the study. They completed an intense training session followed by 3x 8 minutes of sauna, or a placebo treatment which involved rubbing an inert massage oil on chosen body parts while resting in a seated position. 

On the next morning they completed a 4x 50 metre all out swim test. Here’s where things get interesting. The swimmers performed significantly worseafter the sauna recovery compared to the placebo recovery. In fact, using sauna after their training resulted in an average increase in time to complete the swim test by 1.69 seconds, whereas the placebo group decreased their time by an average of 0.66 seconds. Contradictory to most anecdotal reports that sauna causes relaxation, the participants who used sauna after training had significantly higher subjective feelings of stress compared to after placebo.

Research has suggested that the smallest worthwhile change (the minimum improvement in swim time that is practically significant to swimming performance) is 1.2 seconds. Therefore, considering the magnitude of swimming performance deterioration after the sauna “recovery”, it suggests that sauna does have the potential to adversely affect the competitive outcome.

Chinese takeaways

Prior to this study, my opinion on sauna for athletes was that it was extremely unlikely to do harm as long as fluids lost by sweat were replaced. If the client or athlete said they enjoyed doing it, or that it made them feel subjectively better, they would receive little argument from me. Since this new study, my stance has changed somewhat. Now, I think coaches and athletes should be quite cautious with regard to post-exercise sauna. Now you might say “well this was a swimming study”, which is true, however for any athlete who is performing near maximal exercise efforts on one day, with the intention of trying to replicate those efforts the next day…I see no reason why sauna would not be at least somewhat detrimental in line with the recent swimming study findings. I don’t think we need to banish saunas from all athletes, after all the subjective feeling of wellness is no insignificant outcome to an athlete, however that benefit should not outweigh the compromising of performance capacity in my opinion. If you are doing hard consecutive day training sessions, I probably wouldn’t be using sauna in between as an attempted recovery aid.

REFERENCES

Skorski, S., Schimpchen, J., Pfeiffer, M., Ferrauti, A., Kellmann, M., & Meyer, T. (2019). Effects of Postexercise Sauna Bathing on Recovery of Swim Performance. Int J Sports Physiol Perform, 1-7. doi:10.1123/ijspp.2019-0333

Hussain, J., & Cohen, M. (2018). Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review. Evidence-based complementary and alternative medicine: eCAM, 2018, 1857413. https://doi.org/10.1155/2018/1857413

About the author

Jackson is a PhD researcher in Clinical & Sports Nutrition, an accredited Sports Nutritionist, and competitive bodybuilder and boxer. He currently works at the School of Human Sciences, where he has completed a BSc in Sports Science and in Exercise & Health, and an Honours in Exercise Physiology. Instagram @jacksonpeos