If you’re already a physical marvel, strength, stamina, and grit are your friends. It’s likely taken hours out of your day, and days out of your month. Or if you’re a professional athlete, it’s taken your whole life. This is especially true of the time spent on recovery, whether that’s on replenishing lost fluids, calories, oxygen, or on the excruciating joy that is DOMS. Recovery is a necessary evil for athletes of any level, not least to prevent injury, but it’s also painful, expensive, time-consuming and awkward as hell. We could do without the public cowboy walks, thanks.
So what’s the alternative? Most of us will have spied an athlete or two submerging themselves in ice after training or a particularly heavy performance. But it’s not always clear how it helps, and if it could help us too. Here’s what makes cold water therapy such a revolutionary approach to improving athletic recovery and performance.
What happens inside your body when you get into an ice bath after exercise?
Cold water immersion (CWI) is the practice of immersing the body in cold water that is less than 15˚C/59°F. It’s used as a recovery method, usually immediately after a workout as a measure to enhance the healing process.
When you jump into an ice bath, your blood vessels constrict and get smaller. Then, when you get out again, the change in temperature causes them to rapidly reopen. This does a few things:
- It helps flush your muscle’s metabolic waste products out, like lactic acid
- It delivers much needed oxygen and nutrients to the muscles which aid their recovery
- It increases blood flow and speeds circulation (which in turn improves the healing process)
There are other effects on the body after a cold dunk, like:
- Decreased metabolic activity and slowed down physiological processes
- Reduction in tissue swelling and breakdown
- Decreased nerve conduction velocity and muscle spasm
How can cold water therapy benefit training sessions or performances?
The first, and most obvious thing that cold water therapy can do is help the body cool down much faster than it does on its own. Exertional hyperthermia - where the core body temperature exceeds 40oc/105F and the central nervous system becomes dysfunctional - is a real danger for high-performing athletes, but a 2016 study found that a cold shower could relieve it. Ice baths have also been found to improve performance before working out on a hot or humid day.
Cooling the exercised muscles also increases cellular signal, which turns on mitochondrial biogenesis. Additionally in the energy stakes, muscle glycogen is spared after cold water immersion, meaning more left in the muscles for fuelling movement. A study in mice showed that routine cold exposure improved muscle function and exercise performance, demonstrating the effects in action.
If you’re particularly sweaty, there’s more good news. Cold exposure like an ice bath decreases the sweat rate, mitigating the loss of electrolytes, which are essential for athletic performance. Instead of looking at dehydration as the cause of rising core temperature, it’s smarter to look at it the other way around, and reduce your hydration stress in the first place.
At cold temperatures, the body’s metabolism also reduces, which can cause a slow down of physiological processes. This sounds bad, but it helps reduce swelling and tissue breakdown during performance.
Finally, heart rate is reduced and perceived fatigue is reduced after post-exercise cold exposure, allowing you to keep going when your heart and your head would normally say no (which is often where you find that new PB).
How can cold water therapy benefit post-exercise recovery?
After an intense workout, or a race or match, the feeling is unbeatable. The DOMS (Delayed Onset Muscle Soreness), however, are not. The muscles we’ve worked out experience microtrauma and tears in the muscle fibres. This muscle damage is strategic, as it stimulates muscle cell activity which helps in the repair and strengthening of the muscle and leads to hypertrophy (bigger muscle cells) in the long-term. This process is also thought to be the explanation for DOMS, which can start 12-72 hours after the exercise.
There’s already plenty of evidence for how well cold water immersion can combat DOMS, which indicates that it:
- Is more effective for muscle recovery than hot, warm or alternating hot and cold exposure
- Reduces the symptoms of muscle soreness, 24, 48 and 96 hours after exercise, and reduces perceived exertion 24 hours after exercise
- Is most effective at lowering inflammation, along with massages
- Is better at reducing DOMS compared with passive interventions involving rest or no interventions
- Reduces swelling
Inflammation is particularly key in the formation of DOMS, but one neurotransmitter that can help is norepinephrine. A study by Finnish researchers did blood tests on 10 women who took plunges of 20 seconds in water just above freezing, and submitted to full-body cryotherapy sessions. They found they had a two to threefold increase in their norepinephrine levels only a few minutes after exposure. Norepinephrine lowers pain and unruly inflammation, as well as decreasing levels of several inflammatory mediators, which would help explain why a chilly dunk is such a tonic for our post-workout pains. Scientists have been able to show which inflammatory mediators, specifically TNF-alpha and IL-1, were reduced at the end of a five day treatment with cold exposure, indicating systemic inflammatory reduction, which is usually only achieved with medication.
When your body feels the cold, your metabolism decreases. That might sound bad if you’re looking to lose fat, but for the purposes of speeding up athletic recovery, it can be a boon (and good news: there’s evidence that cold water therapy can still aid fat loss. This reduction in your metabolism can slow down the physiological processes of swelling as well as tissue breakdown during performance. One study demonstrated how oedema, fluid-induced swelling, was visibly reduced in participants’ leg which was exposed to cold water after a strenuous run, compared to their leg which was not, which has been backed up by a further study measuring swelling and pain sensation after exhaustive exercise. The potential mechanism for this is vasoconstriction (the narrowing of blood vessels by small muscles in their walls) which has been shown to reduce fluid diffusion into the interstitial space (the compartment that surrounds our tissue cells).
Vasoconstriction isn’t just a powerful process for stemming the swell: it’s a mechanism that can help flush out that pain pundit, lactic acid. The cold you experience when you sit in an ice bath causes your blood vessels to tighten (vasoconstriction) which helps your lymph nodes, our internal waste collectors and disposers, move lactic acid and other toxins out of the body. Norepinephrine also contributes to our vasoconstriction and encourages the biogenesis of mitochondria, our cells’ powerhouses.
The positive impact of a cold plunge on our blood flow, volume and oxygen levels have also been demonstrated, bolstered by the deepend breathing we experience, which increases oxygen levels, heart rate and your overall cardiac function. Cyclists repeatedly performing in the heat were found to better maintain their performance across trials with cold water immersion, which was attributed to the alterations in the core temperature and limb blood flow.
In more general health terms, athletes like winter swimmers have reported significantly decreased tension, fatigue, memory, and mood negative state points in scientific study, as well as relieved pain in those who suffered from rheumatism, fibromyalgia, or asthma. Good sleep is also crucial to athletic performance and recovery, and cold water has been shown to help there too: it can aid your central nervous system, and improve your heart rate variability (HRV) which is an indicator of physical and psychological stress. Good HRV not only increases athletic performance, but is also implicated in good sleep, showing once again how cold water therapy benefits athletes in multi-faceted ways.
When should I use cold water therapy, and which type of athlete benefits the most?
A 2016 meta-analysis of ice bath studies found that the optimal conditions for athletes looking to enhance their muscle recovery and performance came after soaking in water between 10-15oc (50-59oF) for 10 to 15 minutes. This time window was also backed up by another small study that found a 10 minute bath was as beneficial as a 20 minute bath, showing you can get what you need from a speedier dip (great news for those with packed schedules). How long you do it after your workout or performance can matter too, with one study suggesting that you have a 2 hour window afterwards in which to take your plunge in order to reap the benefits for soreness and muscle recovery.
The importance of training cycle timings
Where you are in your training or performance cycle should also be taken into consideration to optimise your results: if you’re in-season and competing regularly, cold water therapy can help dial back inflammation and therefore get you ready faster for your next game or match. If, however, you’re off season, you’re a chronic endurance athlete like a marathoner, or you’re a gym-goer who is currently focused on building muscle and strength, you may want to take a different approach. Some evidence suggests that cold water therapy immediately after a workout may actually impair your progress, because the inflammation process is cut short. This means the later phases of repair and remodelling cannot happen and muscle tissue doesn’t have the opportunity to grow, or that you cannot force adaptation (in the case of long-distance runners).
If this does sound like you, it’s not the end of your cold water journey: instead, some science suggests that you wait 24-48 hours after exercise to allow muscle tissue to start the repair process and promote the body’s training adaptations like strength building and hypertrophy (muscle growth). The same research has also suggested that people who do High Intensity Interval Training (HIIT) workouts or similar total body endurance training will particularly benefit from ice baths’ ability to lower high body temperatures.
The science indicates that your muscle recovery and performance have much to gain from cold water therapy, in a host of different ways, when executed with timing and precision. The body of research showing just how far the benefits of the practice extend for athletes keeps growing, and in the meantime, it continues to be a mainstay in the recovery routines of big names in the ring, on the track, on the court and beyond.
Monk is backed by a collective of anti-ordinary people, including athletes, who are terrified of being average. They live and believe in the transformative power of cold water therapy, and want to bring it to more people so they can fulfil their true performance potential.
Please note: educational information is not the same as medical or psychological advice. This blog post is reviewing published scientific evidence, and all information on this website is presented for educational and informative purposes only. It is not intended to replace professional, medical, or psychological guidance in any capacity.