The Chilly Trend: Unveiling the Truth Behind Ice Baths and Cold Exposure

We are talking about - Ice Ice Baby.

Cold exposure – whether from ice baths, cold showers, cold plunges, or cold-air chambers has been touted as an excellent tool for enhancing recovery and boosting immune function and overall health. Popular health advocates, such as Wim Hoff, have credited cold water immersion with many positive improvements in their health. 

Is it real, or is it wishful thinking? Should we all be taking ice baths? Here is what the research says:

Evidence for Ice baths

There is some good evidence that ice baths have beneficial, measurable effects. The mechanisms for physiological effects of immersing oneself in cold water likely have to do with redistribution of blood flow, vasoconstriction, and the effect of reducing temperature on enzyme activity.

Also, at least some of the positive effects of cold exposure appear to be due to placebo, which includes the belief in the benefit of cold exposure. Acclimating the brain to the routine discomfort of cold is another way cold therapy can work through our minds. Some specific findings-

Enhancing Recovery--Good Evidence! 

Ice baths have been promoted to reduce muscle soreness and speed up recovery after a hard workout. There is some promising evidence that ice baths work! Two recent meta-analyses found that cold water immersion was beneficial for reducing muscle soreness and improving recovery of power and strength.    

Health and Mood--Some Evidence! 

Cold water immersion has also been found to impart measurable benefits to general health. Heart rate variability is a gross measure of how well-balanced our neuroendocrine system is between the stress/fight-or-flight state and the housekeeping/digestion state. Generally, a higher heart rate variability at rest indicates a better balance – i.e., being more in tune with the housekeeping/digestion side while resting.

Regular ice baths after workouts have been shown to increase heart rate variability at rest. Also of note, short-term exposure to ice baths is associated with positive changes in brain activity and mood – including increased feelings of activity, alertness, inspiration, and pride.

Immune Function--Less Evidence!  

A common claim of regular cold plungers is that they feel the practice protects them against sickness. So far, there is only a little research to support this claim. The few available data indicate some measurable short-term changes in post-exercise markers of inflammation following cold-water immersion. Regarding how this relates to one’s odds of getting sick, I could only find one promising study, which found that taking (hot-to-) cold showers regularly reduced self-reported sick days by 29%, which is interesting but not definitive.    

I’ve decided to take the plunge –  how to do it?

If you are sold on trying out cold exposure for yourself, here are some guidelines on best practices. 

There are only rough guidelines for how cold or how long the exposure should last. Ice baths (~50°F) are recommended for an upper limit of 10 minutes, while cold-air cryo chambers (which, at -160°F, are really cold) are suggested for 2-3 minutes at a time. The one study that found cold showers reduce illnesses reported no effect of duration of cold exposure on the odds of illness, so I would recommend shooting for only a few minutes of cold exposure at a time, especially when starting out – why suffer longer than needed?

Timing your cold exposures around workouts may be an important consideration. Cold exposure right after a workout appears to interfere with chemical processes that allow you to build muscle. Happily, this interference effect appears to be transient, so you can enjoy the benefits of cold exposure and build muscle by waiting for about 6 hours after a hard workout before cooling.

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