There are 4 different methods for using water immersion in recovery:

Heat Acclimation & Hot Tubbing

The ONLY known benefit to Hot Water Immersion (hot-tubbing) for athletes is heat acclimation adaptations for athletes not acclimated to hot environments.

• Most professional/elite cyclists recover using cold water immersion or contrast therapy.

Theory vs reality of hot tubs & muscle recovery

Thermotherapy refers to being immersed in water that raises your core body temperature, which would be water that is hotter than 97°F (36°C) and generally between 100 to 115ºF (38 - 46°C).

Of the 4 types of water immersion techniques, thermotherapy (hot-tubbing) is the least effective, even though nearly every training center, health resort, gym, and sports complex has a hot tub or spa.

The theory behind this form of “therapy” is that the hot water increases the flow of nutrients to muscles after exercising by widening the blood vessels, which improves circulation and blood flow.

However, the research shows only an increase in the surface skin temperature and circulation, as the heat doesn’t penetrate deep enough to affect muscles (heat pads do though, as they are hotter and you wear them longer).

muscle damage & avoiding the spa

After you have been active, your muscles are already heated. There is a reason you do a cool-down after a ride and not a “heat-up.”

Intense physical exertion causes trauma to your muscles, including micro-tears. Cold acts as a natural compression and will help aid recovery by reducing swelling and slowing the flow of blood to traumatized areas. Heat, by contrast, makes the swelling and inflammatory response worse. This is why even hot tub manufacturers do not recommend soaking if you have inflamed muscles.

Cycling performance: Science of different water immersion techniques

A 2008 study, published in the International Journal of Sports Medicine compared cold water immersion, hot water immersion, and contrast water therapy as a post-exercise/cycling recovery technique to next day cycling performance.

The results after 14 minutes of hydrotherapy:

• Both Cold Water Immersion (CWI) and Contrast Water Therapy (CWT) enhanced next day cycling performance over 5 days of testing

• Cycle-sprinting was enhanced by both CWI and CWT

• Hot Water Immersion in a spa set at 100°F (38°C) led to nearly a 4% reduction in both sprinting and cycling performance (~4% slower/worse)

While the previous study only looked at next-day performance. How does taking a dip effect sports performance right after a 30-minute soak?

A 2013 study that was published in the European Journal of Applied Physiology, compared cold water immersion, contrast water therapy, and hot water immersion on cycling performance, 40-minutes after soaking.

The researchers’ conclusion:

“Cold water immersion at 15°C (59°F) was the most effective as it was the only treatment that maintained cycling endurance in the subsequent bout”

Hot tub manufactures & there “Science”

If you look at any hot tub/spa website or brochure, you will find all the supposed health benefits of hot tubbing, including benefits to muscle recovery from exercise.

A large hot tub/spa company, says on their website, “studies have shown that both heat and cold therapy can promote healing and prevent muscle damage following exercise.”

If you actually read the study that was cited, you will discover that hot tubs and cold tubs were not even tested. Instead, heat packs and cold packs were applied to the skin. In the case of the heat pack, it was applied for 8 hours. The study also happened to be sponsored by Pfizer pharmaceuticals.

Sitting in a hot tub for 20 minutes is hardly comparable to wearing a hot-pack for 1/3 of the day, but I don’t need to point out the obvious.

Another large hot tub website says,

“one study found that hot tubs and hydrotherapy helps sore muscles because the soaking reduces lactic acid.”

At least this study actually looked at hydrotherapy, however, hot tubbing was not part of the investigation. This research only looked at Contrast Water Therapy that alternated between 53°F (12°C) water and 97°F (36°C) water baths.

The researchers' conclusion was

“contrast water immersion is a valid and effective means of accelerating recovery from high-intensity exercise in both males and females”

This is good to know. But this is clearly not the same as soaking in a spa or hot tub after a day of riding

Hot Tubs & Marketing

The reasons these hot tub companies resort to “trickery” is because there are no real benefits to hot tubbing for muscular recovery or sports performance (unless acclimatizing to hot environments).

Saunas vs hot tub & recovery

Hot tubs and saunas are both equally ineffective at promoting muscle recovery and subsequent sports performance. Saunas, like hot tubs, increase core body temperature, which places considerable strain on the thermoregulatory and circulatory systems, especially right after exercising.

Why is a sauna bad for sports/exercise recovery?

Many bodily systems are activated to maintain a healthy temperature. As a result, your heart rate doubles, you sweat profusely, blood flow becomes altered, and your body releases cortisol and catecholamines.  

All of which impose additional stress after you just stressed the body sufficiently by exercising or engaging in intense physical activity.

Sauna bathing for endurance training

If you are looking to add sauna bathing to your training regimen (as opposed to recovery strategy) there are some benefits. Most notably, an expansion of plasma volume, which will improve endurance performance as the physiological responses are similar to those produced during vigorous walking (for sedentary and out of shape people).

Final thought

Hot tubs certainly feel wonderful, but that is the extent of their benefit for muscle recovery and won’t do anything for your riding performance.

If you are looking for some easy to implement post-exercise recovery strategies, you can always try compression socks, massage, naps, or contrast water therapy (~15-minutes).

If you just want to relax while soaking in a tub of hot water under the stars, then cheers.

For some easy to implement recovery tips, check out my blog on “Recovery Techniques”

Jesse is Director of Pedal Chile and lives in Valdivia, Chile. Jesse has a Master of Science in Health & Human Performance and a Bachelor of Science in Kinesiology. Hobbies: MTBing, snowboarding, reading, taster of craft beers, & researcher.

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Sources ‌for “Hot Tub & Muscle Recovery”

1. Al Haddad, H., et al., Effect of cold or thermoneutral water immersion on post-exercise heart rate recovery and heart rate variability indices, Auton. Neurosci. (2010), doi:10.1016/j.autneu.2010.03.017

2. Burke, Darren G. et al. “Effects of Hot or Cold Water Immersion and Modified Proprioceptive Neuromuscular Facilitation Flexibility Exercise on Hamstring Length.” Journal of athletic training vol. 36,1 (2001): 16-19.

3. Cheung, S.S. and Zabala, M. (2017). Cycling science. Champaign, Il: Human Kinetics.

4. Crampton, D., Donne, B., Warmington, S.A. and Egaña, M. (2013). Cycling time to failure is better maintained by cold than contrast or thermoneutral lower-body water immersion in normothermia. European Journal of Applied Physiology, 113(12), pp.3059–3067.

5. Laukkanen, J.A., Laukkanen, T. and Kunutsor, S.K. (2018). Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence. Mayo Clinic Proceedings, [online] 93(8), pp.1111–1121.

6. Leicht, C.A., James, L.J., Briscoe, J.H.B. and Hoekstra, S.P. (2019). Hot water immersion acutely increases postprandial glucose concentrations. Physiological Reports, 7(20).

7. Morton, R.H. (2007). Contrast water immersion hastens plasma lactate decrease after intense anaerobic exercise. Journal of Science and Medicine in Sport, 10(6), pp.467–470.

8. Petrofsky, J.S., Khowailed, I.A., Lee, H., Berk, L., Bains, G.S., Akerkar, S., Shah, J., Al-Dabbak, F. and Laymon, M.S. (2015). Cold Vs. Heat After Exercise—Is There a Clear Winner for Muscle Soreness. Journal of Strength and Conditioning Research, 29(11), pp.3245–3252.

9. Scoon, G.S.M., Hopkins, W.G., Mayhew, S. and 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), pp.259–262.

10. Skorski, S., Schimpchen, J., Pfeiffer, M., Ferrauti, A., Kellmann, M. and Meyer, T. (2019). Effects of Postexercise Sauna Bathing on Recovery of Swim Performance. International Journal of Sports Physiology and Performance, pp.1–7.

11. Vaile, J., Halson, S., Gill, N. and Dawson, B. (2008). Effect of Hydrotherapy on Recovery from Fatigue. International Journal of Sports Medicine, 29(7), pp.539–544.

12. Wardle, Jonathan. (2013). Hydrotherapy: A forgotten Australian therapeutic modality. Australian Journal of Medical Herbalism. 25. 12-17.

13. Wharton, J., Wharton, P. and Browning, B. (2002). The Whartons’ complete book of fitness. New York: Three Rivers Press.

14. Wilcock, I.M., Cronin, J.B. and Hing, W.A. (2006). Physiological Response to Water Immersion. Sports Medicine, 36(9), pp.747–765.

15. Zurawlew, M.J., Mee, J.A. and Walsh, N.P. (2019). Post-exercise Hot Water Immersion Elicits Heat Acclimation Adaptations That Are Retained for at Least Two Weeks. Frontiers in Physiology, 10.