It's funny how fitness trends and science circle back around as popular influencers in sport or fitness put thing online. A recent trend online has been athletes getting into ice baths and praising the effectiveness it is having on their bodies and recovery.
Is it really true? Should you take the time to try to getting into some cold water? What are the benefits really?
Let's be clear.
Done correctly, deliberate cold exposure can positively affect brain and body health. Let's talk about some of those benefits and how best to access them. Research now supports this long-practiced recovery technique so you can know more specifics for how to get the most out of it.
How cold do it have to be for benefits?
It depends on your current tolerance. Some people tolerate cold better than others. The key is to aim for a temperature that evokes the thought, "This is really cold (!), and I want to get out, BUT I can safely stay in." For some people, that temperature might be 60°F (15.6°C), whereas for others, 45°F (7.2°C).
The key is: the colder the stimulus (water immersion, shower, etc.), the shorter amount of time you need to expose yourself to the cold. One study showed significant and prolonged increases in dopamine when people were in cool (60°F) water for about an hour up to their neck, with their head above water. Other studies describe significant increases in epinephrine from just 20 seconds in very cold water (About 40°F or 4.4°C). So you can get benefits from both and just like exercise, you can build up your tolerance over time the more you do it.
Should I do ice bath, cold shower, or cryo chamber?
Most of the studies use ice baths or cold water immersion to the neck. Those are best, but many people do not have access to a large ice bath, so a cold shower may still get you some benefits. Cryo chambers are not well researched enough yet to consider in this article. They are also largely expensive and inaccessible for people.
What are the benefits?
Increased Energy and Focus
Deliberate cold exposure causes a significant release of epinephrine (aka adrenaline) and norepinephrine (aka noradrenaline) in the brain and body. These neurochemicals make us feel alert and can make us feel agitated and as if we need to move or vocalize during the cold exposure. The prolonged affect can help you stay mentally focused for other mental tasks or challenges later on.
Building Resilience & Grit
By forcing yourself to embrace the stress of cold exposure as a meaningful self-directed challenge (i.e., stressor), you exert what is called 'top-down control' over deeper brain centers that regulate reflexive states. By mentally forcing yourself to stay in water and breath, you are flexing your mental muscles to say no to strong impulses to quit and build resilience and grit to keep going. This is a skill that carries over into other areas of life, allowing you to cope better and maintain a calm, clear mind. That can make a big difference in helping you with other fitness, competition, work, or life related challenges in the future!
Enhancing Your Mood
Cold exposure causes the prolonged release of dopamine. Dopamine is a powerful molecule capable of elevating mood, enhancing focus, attention, goal-directed behavior, etc. Even short bouts of cold exposure can cause a lasting increase in dopamine and sustained elevation of mood, energy, and focus.
In the short-term, cold exposure increases metabolism as the body has to burn calories to increase core body temperature. You have to burn calories to warm yourself back up! The total calories burned from the cold exposure are not that significant. However, deliberate cold exposure can aid in the conversion of white fat (energy storage) to beige or brown fat (which are highly metabolically active) which can be beneficial for:
Allowing people to feel more comfortable in the cold (i.e., cold adaptation)
Triggering further and more sustained increases in metabolism
Of course, calories on (consumed) versus calories out (metabolized) or "energy balance" governs whether you gain, lose, or maintain weight. There are no short cuts to escaping the laws of thermodynamics.
Deliberate cold exposure causes a form of blood flow restriction to the extremities as your body diverts blood flow to your core to keep your core temperature warm. When you get out of the cold, your body naturally warms itself and returns fluid, blood flow, and nutrients to your joints and extremities. Along with the hormone responses of deliberate cold exposure, this can have a powerful effect on joint health and recovery.
A meta-analysis of cold-water immersion effects on recovery found that cold exposure can be a highly effective recovery tool after high-intensity exercise or endurance training. Short interval (< 5 mins), cold water immersion demonstrated positive outcomes for muscle power, perceived recovery, and decreased muscle soreness (in part due to a reduction in circulating creatine kinases).
How to do it?
Consider doing deliberate cold exposure in the shower or ice bath (or cold body of water) for 11 minutes per week TOTAL. NOT per session, but rather, 2-4 sessions lasting 1-5 mins each distributed across the week. Again, the water temperature should be uncomfortably cold yet safe to stay in for a few minutes. You can do more, but this should be the minimum to achieve the benefits of cold exposure. Feel free to mix up the temperature and durations to find what works best for you.
No Timer? Here is a different approach.
Count the number of mental 'walls' you have to break through when doing the cold exposure. For example, one 'wall' may be just getting in. Aim for 3-5 walls every time you do a cold exposure. By doing this, you will accumulate time and get the same effect.
When to do it?
Before training. When done after training, cold exposure can decrease gains in hypertrophy, strength or endurance if done in the 4 hours or so after training. It's better to wait 6 to 8 or more hours until after training,. If your goal is simply to recover without adaptation (for instance, when in a competition mode and not trying to get better, stronger, etc.), then doing it directly after training is fine.
The best time of day to do deliberate cold exposure is in the morning. According to your circadian rhythm, you body is already naturally warming itself in the morning hours and it is naturally cooling itself in the evening in preparation for sleep (our lowest body temperature is when we are sleeping). So, to prevent yourself from getting rush that jazzes you up so much that you cannot fall asleep, try to get your cold exposure in the morning hours when your body is already warming itself.
Want to know more in-depth? Keep reading.
The Søeberg Principle based on deliberate cold researcher Dr. Susanna Søebergis: To enhance the metabolic effects of cold, force your body to reheat on its own. Or "End With Cold."
Also, allowing your body to shiver may enhance metabolic increases from cold. Shivering causes the release of succinate from muscles and further activates brown fat thermogenesis.
Try this protocol to increase shivering, either during or immediately after cold exposure:
Don't huddle or cross your arms while in the cold or after getting out. Also, don't towel off. Let your body reheat and dry off naturally. Admittedly, this is tough. Unless doing deliberate cold exposure on a hot sunny day, admittedly, I prefer to take a hot shower and towel dry after cold exposure, but I am no doubt limiting the metabolic effect by doing that.
Never get into a dangerous body of water. Also, never do deliberate hyperventilation (breathing really fast) before or during cold water (or any water!) immersion. Start slow (warmer than colder)—as cold shock is possible; just as with lifting weights or other forms of exercise, you'll need to find the right temperature for you, yet prioritize safety.
Thanks for reading!
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