Cold Water Immersion - What's the Deal With It?
In the past 5 years there has been increasing popularity around cryotherapy, in the form of cold water immersion, as a recovery tool for athletes. It seems every podcast has had an episode about cold water immersion. Cold water plunge pools are popping up in gyms and social media feeds are filled with celebrities and athletes doing it. So what is the deal with it? Is it actually helping our muscles to recover more quickly? Does it boost your immune system? Does it improve mood? Is it only a practice in mental toughness? Is it just a fad? How long should you be doing it for? How often? So many questions.
In this blog, I will lay out some of the research surrounding cold water immersion and attempt to answer some of those common questions.
Does it help with muscle recovery?
This seems to be the big question. Cold baths have been used in training rooms for decades to help ease sore muscles and joints after a hard practice or game. But other than freezing the skin and constricting blood flow is it actually aiding in recovery? To be honest, there doesn’t seem to be a clear answer either way.
In this new study, male volleyball players performed the same resistance training protocol and immediately afterwards did 15 minutes of one of the following recovery methods: passive control (sitting at room temperature), contrast bath (alternating hot and cold water immersion), hot water immersion, or cold water immersion. The athletes that did the hot water immersion had statistically significant improvements in sleep quality, reduced feeling of fatigue, and higher testosterone concentration than all other groups. The cold water immersion group showed no statistically significant differences between the other groups.
However, other research has shown that the time of exposure is a very important factor. For instance, this meta-analysis found that short intervals (less than 5 minutes) can improve muscle power, perceived recovery and reduction in creatine kinase leading to less muscle soreness. It is also important to consider the time that elapses between a training session and using cold immersion. It is best to wait 6 to 8 hours or more after training before using cold immersion therapy. Anything less than that can limit hypertrophy gains.
Does it boost the immune system?
Being exposed to cold water will make your cells work harder in order to maintain your core body temperature. This means that you will burn some calories during cold water immersion which will lead to the conversion of white fat to the more highly metabolic brown fat.
There has also been some research that shows that cold water swimming can actually increase white blood cell production which will help us fight off diseases. However, this has to be taken with a grain of salt as there is no way to tell if the benefit came from the cold water or the act of swimming.
Does it improve your mood?
Cold water immersion raises the levels of epinephrine and norepinephrine in our bodies. These neurotransmitters raise our level of agitation while immersed in the cold which is why we may shout, curse, and brace bodies as best we can against the cold. However, the cold will elicit our bodies to continue to release these chemicals in addition to the hormone dopamine even after we have re-warmed ourselves. Albeit temporary, this can lead to a higher level of energy, alertness, and overall mood.
Does it help develop mental toughness?
Short answer - Yes!
This seems to be the most well studied and agreed upon benefit of cold water immersion. Purposefully exposing yourself to a stressor such as cold immersion will help you develop and fine tune your brain’s ability to have “top-down control” on your deeper brain centers that control your reflexes. You will be using your inner self-talk (prefrontal cortex) to control your body’s reflexes. This is how you build “grit” and “resilience” that can translate over to other areas of your life that require you to push your mental and physical limits. It truly is mind over matter.
The Logistics - How Long, How Often, What Temperature?
Just a few safety points: Never get into a dangerous body of water, start warmer and then gradually get colder, build up your exposure time gradually, learn to breathe properly, make sure someone knows what you are doing and have a way to reach out for help if needed. Check with your doctor if you have any underlying medical conditions that concern you before beginning this as a regular practice.
There is no exact temperature that has proven more beneficial than others. Basically, you want it to be a temperature that makes you say “Damn, that’s REALLY cold! But I can safely stay in it.” Your body will naturally develop a thermal layer around you when staying still so move your arms around a bit to break that thermal layer and get the full effect of the cold.
The research varies on how long and how often cold water immersion should be done. It really depends on your goals. If you are not doing it for physical recovery but rather as a practice in mental toughness then you can expose yourself to longer time frames. But if you are doing this for physical recovery, keep your sessions short. 2-4 sessions per week at 1-5 minute bouts. This should total 11 minutes at most per week.
Big Take-Aways:
It can help with muscle recovery in short bouts of 1-5 minutes performed 6-8 hours after training. If you don’t care about hypertrophy gains, then it is a toss up - both hot and cold immersion have benefits for recovery.
It has some small benefits on your metabolism and immune system function.
Through the release of neurotransmitters, it will temporarily elevate your mood and make you more alert.
It is most beneficial as a means of training mental toughness, grit, and resilience.
Shannon Hall, PT, DPT
Sources:
https://hubermanlab.com/the-science-and-use-of-cold-exposure-for-health-and-performance/
https://link.springer.com/article/10.1007/s40279-022-01644-9