Triathletes are unique individuals who possess some level of obsession, are data-driven, and are usually overtrained rather than undertrained. However, like all athletes, we look for ways to enhance our recovery from repeated bouts of exercise so we are able to apply a repeat high training stress shortly after a previous training exposure in order to maximize adaptation and performance.   

Many factors impact recovery; genetics and age are two factors over which we have little control. There are many other recovery adjuncts, some proven and others anecdotal, including sleep, nutrition, pneumatic compression devices, compression clothing, even electrical muscle stimulation (EMS) or pulsed electromagnetic field (PEMF) therapy.

One very popular, inexpensive, and easily available method for post-race or past-training recovery often used is cold water immersion. Athletes of all disciplines sit in an ice bath because it “helps with recovery” and reduces muscle soreness. But does it?

This article will focus on cold water immersion (CWI) as a recovery aid. Keep in mind that the use of cold water or ice packs may also be used as an intervention to cool an athlete who is hyperthermic from a hot environment coupled with exercise. Cold therapy is also used to reduce pain and swelling of an acutely injured joint or muscle.

Medically, targeted temperature management, specifically cooling patients for about 24 hours at 32⁰C -34⁰C (normal body temperature is 37⁰C) is now standard of care in certain patients who experience a cardiac arrest. These interventions have shown to improve both survival and neurological outcomes. These other indications are beyond the scope of this article. 

The goal is to determine what evidence exists to support the use of CWI as an aid to enhance recovery and decrease muscle soreness.   

An extensive PUBMED literature search was performed to review published scientific studies and to summarize what triathletes need to know. There are many factors that need to be taken considered, including how we actually define successful recovery.

• Should recovery be based on the athlete’s subjective feelings, such as rating of perceived exertion (RPE) or delayed onset muscle soreness (DOMS)?

• How about objective biometrics such as resting heart rate or HR variability (HRV)?

• Biomarkers also exist, including creatine kinase (CK), myoglobin, C-reactive protein (CRP), Interleukin-6 (IL-6), blood lactate and others.

• Finally, should recovery be based on subsequent performance of the next training session or race?

The literature is filled with numerous studies that look at different types of training as well as different recovery measurements and treatments; thus, there are many variables.

1. Type of training, e.g., resistance and strength, speed, endurance
2. Type of sport (cycling, swimming, sprinting, long-distance running, rugby, basketball, Jui-Jitsu and many more)
3. Different definitions of how the efficacy of CWI as a recovery aid was measured
4. Duration of exercise, e.g., sprint, marathon, ultra-endurance sport
5. Time period between repeat performance, e.g., 15 min, next day
6. Different temperature of water used in CWI (i.e., 5 ⁰C to 15 ⁰C)

As a result, there is a lack of consistent and reproducible evidence. There is no gold standard or best definition of an objective measurement of enhanced recovery. Some studies show improvements in certain measures such as HRV and power, with no difference in muscle soreness (1). One can accept that CWI may help with some variables as long as there is no harm to others.  But the studies are not straightforward.

In resistance training, for example, some literature suggests that CWI may actually alter muscle adaptation and attenuate hypertrophy, so if your goal is muscle strength and growth, perhaps reconsider (2, 3). In contrast, CWI may actually augment a desired endurance adaptation response by facilitating the expression of mitochondrial biogenesis after a single endurance training session but fail to demonstrate a continued effect with long term endurance training (3).

In the holy grail of triathlon, 33 triathletes (22 male, 11 female) who were racing in the IRONMAN World Championship volunteered to participate in a study to assess the effects of CWI on muscle soreness, muscle damage and inflammation. Athlete subjects were at an average age of 40 +/- 11 years. After the race, the participants were randomized to either (a) 10 min of CWI in 10 ⁰C or (b) no immersion (control group). 

Various measurements including DOMS, myoglobin, CK, Cortisol, IL-6 and CRP we taken of the participants as they were examined at the end of the intervention, as well as 16 and 40 hours after.  The conclusion, a single bout of CWI did not provide any physiological benefit within the 40 hours post-race (4). 

Of course every study has limitations. Is a 140.6 mile event the best venue to assess the value of CWI? What if this was an international distance where competitors were racing at a higher race intensity? 

So where does that leave us?

In summary, there is no clear and consistent evidence that CWI helps in recovery. The contradictory results may reflect nuances associated with different sports and exercise type (endurance vs. resistance vs. sprint), individual differences in body composition, the duration of events, external environment, the temperature of water, duration of immersion, and other factors. More research is needed to recommend optimal recovery protocols using CWI. There may be advantages in some areas that are offset by disadvantages in other areas.

For now, the use of CWI remains a personal choice that may help some. Personally, I opt for compression garments, active recovery, and sleep where the science is stronger.

Robert Takla, MD, MBA, FACEP is the Medical Director and Chair of Emergency Medicine for Ascension St John hospital in Detroit. He is a USA Triathlon and USA Cycling age-group athlete participating in numerous triathlon and cycling events. He is a fellow of the American College of Emergency Physicians and section member of Sports Medicine and lead physician and medical support for Stout multi-century ride across Michigan. Dr. Takla has a passion for the pursuit of physical, mental, and emotional health and fitness and helping others maximize their health and wellness goals https://www.linkedin.com/in/roberttakla/. 

Section Editor: Andrew Getzin, MD is the head team physician for USA triathlon. He is a USAT level 1 coach, many year USAT age-group All-American and has qualified and competed in Kona. He is a fellow of the American College of Sports Medicine. Dr. Getzin is the medical director of Cayuga Medical Center Sports Medicine and Athletic Performance in Ithaca, New York, www.cayugamed.org/sportsmedicine and the director of their shortness of breath in the athlete clinic, www.cayugamed.org/sob.

References

1. Eur J Sport Sci. 2018 Feb; 18(1) 54-61. 

2. Am J Physiol Regul Integr Comp Physiol. 2018 June 1:314(6) R824-R833.

3. Sport Med 2018 Jun;48(6): 1369-1387.

4. J Sci Med Sport 2018 Aug;21(8):846-851.