3 body system benefits of ice baths for athletes
Cold plunge boosts exercise performance
In Precool Your Workout I wrote about the astounding gains in exercise performance that can be obtained by cooling the body prior to and during strenuous exercise. For example, Stanford scientists Craig Heller, PhD and Dennis Grahn, PhD at Stanford University measured gains of 40% in bench press and and 144% in pullup work volumes resulting from percooling during a workout (Grahn et al. 2005, Grahn et al. 2012). Their findings are so remarkable that they inspired fellow Stanford Professor Andrew Huberman, PhD to say:
Thermoregulation can be leveraged to greatly increase our performance in athletics and mental performance. Learning to control your core body temperature is one of the most, if not the most powerful thing you can do to optimize mental and physical performance. - Andrew Huberman, PhD (2021)
Other studies corroborate the Stanford findings. For example, when researchers in Poland measured the skin temperature of the 23 male subjects immediately after strenuous exercise, they found that subjects who cooled the fastest were also exhibited the greatest cardiovascular fitness levels (Jastrzebska et al. 2022). Those results are consistent with prior findings measuring significant gains from cooling in all types of exercise, including runners (Spannagl et al. 2023) and cyclists (Fenemor et al. 2022). Moreover, the typical advice that using cold therapy after exercise to speed recovery is misguided. What most people don't realize is that Precooling Speeds Recovery even better than a post-workout ice bath.
The vast majority of studies in athletes have been related to cooling right before of during competition. There has never been a systematic guide to the use of ice baths in longer-term training programs. Nonetheless, based on my research, the San Francisco 49'ers used Morozko while training for Super Bowl LVIII in Las Vegas.
Whether before or after a workout, there are three bodily systems that might be positively influenced by cold plunge or ice bath training leading up to competition:
Mental.
Metabolic.
Injury repair.
Mental benefits of ice bath for athletes
Perhaps better than any extreme athlete, David Goggins understands the importance of mental toughness during competition. As a Navy SEAL and ultra-long distance runner, Goggins pushes himself farther than even the most accomplished professional athletes would probably consider reasonable.
Huberman speculates that Goggin's incredible resolve may be related to a part of the brain called the anterior midcingulate cortex (AMCC) where willpower, tenacity, and resilience resides. Huberman explains that this area of the brain is larger in athletes and in long-lived individuals, but he emphasizes that the only way to grow and maintain this brain region is to practice doing hard things that we don't want to do.
If you love the ice bath, then guess what? Your anterior midcingulate cortex (AMCC) does not grow. But if you hate the cold water, then the AMCC gets bigger. - Andrew Huberman, PhD (2024)
While there are other mental benefits to ice bath therapy, including protection against brain injury and improved memory, an increased AMCC may be the single greatest mental contribution to improved athletic performance -- at least the the extent that it allows the brain to recruit additional resources at critical moments in the competition that call for deeper resolve.
Although there has never been a systematic study of the response of the AMCC to cold stimulation, analogous studies show that brain responses in the ice bath change rapidly at first and change more slowly thereafter. For example, in Ice Bath Boosts the Brain I described research conducted by Jospeh Dituri, PhD at the University of South Florida that showed massive increases in brain connectivity and processing speed when immersed in a 33F Morozko ice bath. According to Dituri, who specializes in brain health and recovery from traumatic brain injury, these benefits occur in less than five minutes of exposure. Moreover, in Ice Bath Psychology, I reported on data gather from the Muse Headset that shows brain responses to cold water immersion are immediate and stable.
What that suggests is that the AMCC benefits of the ice bath will be found at Temperatures Cold Enough to Frighten, rather than the long duration, 30-minute ice bath that Deontay Wilder did three days before his fight in Riyadh, Saudi Arabia. If mental toughness without metabolic injury was his goal, he may have been better off Microdosing the Ice Bath, rather than old risking Ice Bath Overdose.
To use ice baths to build tenacity before a big competition, go cold enough to hate the ice bath, but limit duration to just long enough to regain breath control and calm the central nervous system.
Metabolic benefits of ice bath for athletes
There are two mechanisms by which ice bath training can benefit metabolism to increase power and endurance during competition:
Mitochondrial enhancement, and
Endogenous ketone production.
Mitochondrial benefits of ice bath for athletes
Muscle cells are powered by tiny organelles called mitochondria that convert fat and glucose stores into ATP for powering mechanical work. There are thousands of mitochondria inside each muscle cell, and the action of the muscle depends directly on the quantity and quality of the mitochondria within it.
Intense exercise training temporarily overloads muscle mitochondria, causing them to produce excess reactive oxygen species (ROS) at a rate faster than melatonin and other electron donors can absorb them. It is the presence of those excess ROS that both damage mitochondrial DNA and signal the removal of those damaged mitochondria (mitophagy) and their replacement with new (mitobiogenesis). Most athletes will slow their training regimen and increase rest in the days leading up to an intense competition -- a practice that will optimize mitochondrial function for the day of the event.
What few athletes realize is that exercise is not the only type of training that improves mitochondrial function. Cold training also promotes improved mitochondrial function. For example, in Ice Baths for Mitochondrial Therapy, I described the research showing that cold exposure can reverse aging by restoring mitochondrial function -- just like exercise. However, what I did not explain was that evidence in mice suggests combining cold and exercise training is more effective for building muscle mitochondria than either one alone (e.g., Chung et al. 2017).
One way to understand this phenomenon is to think about what happens when the muscles shiver in the the cold. Shivering is the process of rapid-fire muscle contractions for thermogenesis, rather than for exercise. During shivering, the mitochondria are working at a high rate of energy conversion to keep the muscle twitching. Thus, shivering is like a workout for muscle mitochondria.
In a shivering muscle, mitochondrial reactions are exactly the same as during normal isometric muscle contraction. Cold exposure often causes changes in muscle metabolism that increase aerobic capacity and fatty acid oxidation. - Hohtola 2004
As with exercise, shivering causes mitochondrial overloading that stimulates ROS production. Both exercise and shivering are examples of hormetic stress -- i.e., stress that makes the body stronger. However, both stressor must be accompanied by periods of rest and recovery to obtain maximum benefits.
No one knows the optimal amount of time for mitochondrial recovery after an episode of intense shivering in human beings. It may be that Deontay Wilder's three days of recovery is sufficient for mitophagy and mitobiogenesis in muscles to build new metabolic capacity. However, in How to Increase Brown Fat I wrote that cold acclimation typically takes 7-10 days of regular cold exposure. Using that measure as a yardstick, it may be sensible to avoid episodes of cold training that cause anything more than mild shivering in the week prior to a competition.
To maximize metabolic gains from cold training in anticipation of competition, keep ice bath sessions short enough to avoid activating the shiver response in the week prior to competition.
Benefits of Ice Bath Ketosis for Athletes
Bodily energy reserves are stored in two ways: glucose and fat. During sudden increases in energy demand, the glucose reserves stored in the bloodstream and liver are consumed first. However, the because glucose stores are so small, the body must switch over to fat metabolism for extended periods of exercise.
Ketones are a product of fat metabolism, and there is some evidence that several neurological and physiological functions perform better when the body is in a state of ketosis. For example, Ben Greenfield reports that he obtained the best triathlon results of his life while in ketosis, while his "levels of good cholesterol, vitamin D, and anti-inflammatory fatty acids skyrocketed" (Greenfield 2020). Nonetheless, effects in sprint competitions may be different from endurance.
The science of ketosis for exercise performance has been frustrated by confusion about how to induce ketosis.
Previous evidence on the role of ketone bodies to fuel muscular work in humans have been confounded by the inability to elevate ketone concentrations without the effects of starvation or elevated fatty acids. - Cox & Clarke 2014
The idea that a ketogenic diet requires or mimics starvation is a popular misconception. In fact, ketosis can be obtained while eating a healthy, high energy diet by limiting carbohydrate intake to less than about 40 grams/day and instead eating more protein and fat. However, the transition typically takes three days and can be accompanied by symptoms of carbohydrate withdrawal that should be avoided during athletic competition.
What most people don't realize is that an ice bath is the fastest way to stimulate production of endogenous ketones. As I wrote in Ice Bath for Fast Keto, an ice bath of 2-4 minutes at 34F can increase ketone levels in the urine, in spite of a high carbohydrate meal. Thus, athletes preparing for an endurance competition can accelerate their transition into ketosis by practicing ice baths after meals.
To maintain ketosis in preparation for athletics competition, use a short, freezing cold ice bath to clear glucose from the bloodstream and stimulate endogenous ketone production.
Injury Recovery Benefits of Ice Bath
In addition to the metabolic and mental benefits of ice bath training in preparation for a critical competition, there remains the special case of injury recovery. In particular, ice bath therapy has been proven effective to reduce the pain of inflammation that often accompanies injury in muscle and connective tissue, and in joints. In fact, cryotherapy is so effective for reducing pain and soreness that it has long been the practice to cold plunge after workouts, despite the loss of anabolic gains.
Inflammation in response to exercise is part of the body's natural cycle of recovery from hormetic stress. In healthy human beings, temporary inflammation can accelerate gains from exercise.
To maximize gains from training, do not ice bath less than four hours following a workout.
However, there is an exception to this rule. When rapid recovery is required between multiple rounds of competition, such as in the Tour de France, cryotherapy may accelerate recovery to peak competitive form (Kwiecien & McHugh 2021).
A similar phenomenon can be applied to cryotherapy for injury recovery. Where the inflammation of injury interferes with performance, ice bath training can be a nonpharmacological intervention for pain relief and accelerated healing -- especially when contrasted with heat (e.g., sauna) and/or red light therapy. For example, in Are You Getting Enough Vasoconstriction? I wrote about the circulatory benefits of contrasting cold water and dry heat therapies to improve circulation. In that article, I cautioned against using the hot tub for thermal contrast therapy, because a phenomenon called hidromeiosis causes vasoconstriction (rather than vasodilation) when skin is warm and wet. That is, the hot tub only promotes circulation through the portions of the body that are not submerged, and thus it should not be combined with whole-body cold water immersion.
When the athlete is able to exercise parts of the body that are not injured, the most promising protocol for injury recovery is ice bath -> exercise -> dry sauna + red light on the affected area. For example, an athlete with an elbow injury may benefit from a whole-body cold plunge that include immersion of the elbow, followed by approximately two minutes of squats or lunges to exercise the legs (not the elbow) for every minute of cold therapy, finished with sufficient dry sauna to ensure a heavy sweat & red/infrared light directly on the injured elbow.
To accelerate recovery from injury in preparation for competition, use 2-4 minutes of ice bath below 40F, light exercise in parts of the body that are free from injury, then dry heat sauna & red light on injuried areas -- right up until the day of the competition.
Summary
During off- and pre-season training, or between competitions, precooling with an ice bath or cold plunge prior to a workout allows the athlete to work harder during training sessions, recover faster, and maximize anabolic gains. However, in the days leading up to a critical competition it may be advantageous to modify cold training protocols with the following recommendations in mind:
Cold Plunge Protocols for Performance
Go cold and short. To build mental toughness and increase the size of the anterior midcingulate cortex, set the ice bath to temperatures that maximize feeling of discomfort in the first 15 seconds. However, do not extend the duration of the plunge so long that shivering is induced. Avoid extended plunges less than a week prior to competition.
Ice bath prior to exercise, not after. Precooling boosts exercise capacity, maximizes anabolic gains, and better prepares the body for competition. The only exception to this rule is for athletes who are recovering between rounds of intense exercise -- for example, during multiday tournaments (e.g., tennis, cycling).
Contrast wet cold with dry heat. Avoid combining ice baths with hot tubs. Instead, pair ice bath with dry sauna to maximize circulatory benefits.
Precool your competition, if you can. Maximum performance will be found when beginning the competition feeling a little cold, and continuing to percool during the contest.
References
Cox PJ, Clarke K. Acute nutritional ketosis: implications for exercise performance and metabolism. Extreme physiology & medicine. 2014 Dec;3:1-9.
Chung N, Park J, Lim K. The effects of exercise and cold exposure on mitochondrial biogenesis in skeletal muscle and white adipose tissue. Journal of exercise nutrition & biochemistry. 2017 Jun 6;21(2):39.
Grahn DA, Cao VH, Heller HC. Heat extraction through the palm of one hand improves aerobic exercise endurance in a hot environment. Journal of Applied Physiology. 2005 Sep;99(3):972-8.
Grahn DA, Cao VH, Nguyen CM, Liu MT, Heller HC. Work volume and strength training responses to resistive exercise improve with periodic heat extraction from the palm. The Journal of Strength & Conditioning Research. 2012 Sep 1;26(9):2558-69.
Hohtola E. Shivering thermogenesis in birds and mammals. In Life in the cold: evolution, mechanisms, adaptation, and application. 12th International Hibernation Symposium 2004 Jul (pp. 241-252). Institute of Arctic Biology.
Jastrzębska AD, Hebisz R, Hebisz P. Temporal Skin Temperature as an Indicator of Cardiorespiratory Fitness Assessed with Selected Methods. Biology. 2022 Jun 21;11(7):948.
Kwiecien SY, McHugh MP. The cold truth: the role of cryotherapy in the treatment of injury and recovery from exercise. European journal of applied physiology. 2021 Aug;121(8):2125-42.
Spannagl BJ, Willems ME, West AT. Effects Of A Head-Cooling Cap On 5-Km Running Performance In The Heat. International journal of exercise science. 2023;16(6):193.
About the Author
Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience.