The 4 T’s of Cold Exposure
“If you can't get an ice bath at the temperature that Wim (Hof) does it, I don't think you'll get the full results.”
That was a comment from someone I was chatting to online and it got me thinking. A lot.
About the opposing cold exposure camps (cryotherapy vs ice bath vs cold shower), about the ‘right’ and ‘wrong’ ways to practice (water temperature, length of time etc.) and the mixed messages that are out there (have an ice bath straight after doing the breathing technique).
It also got me thinking about perfectionism, and how we often let the fear of not doing something 100% perfectly stop us from even attempting it in the first place, or diminish the joy we get from doing an activity.
That’s why I want to unpack the above quote and show you that while factors like temperature, time, type and technique play a role in providing benefits of cold exposure, they’re not the most important, that your intention and a consistent practice (whatever that looks like for you) are far more important and that above all, that you make more progress with love than hate.
Time poor? Remember these catchy little phrases in your cold exposure practice ;-)
Connection beats perfection
Doing something is better than doing nothing
Throw away the dogmas
Ice bath, cold shower or cryo? Does it matter?
Discussions about cold exposure inadvertently revolve around four topics:
Let me start by saying that yes, temperature does play a part in the benefits of cold exposure.
Exposure to cold temperatures triggers our body’s natural fight-or-flight response (through activation of the sympathetic nervous system). This reaction to the cold causes a sharp increase in the release of noradrenaline (or norepinephrine depending on the continent you live) - an important hormone and neurotransmitter responsible for increasing vasoconstriction - which helps to preserve body heat and protect our vital organs in cold temperatures.
From several studies, this response does appear to have a temperature threshold, with this study showing that for the same length of exposure time, 20°C water did not activate noradrenaline release, while exposure at 14°C saw a 530% increase!
Another temperature related factor is the activation of brown adipose tissue (brown fat) - mitochondria-dense fat cells that play a role in the ‘fat burning’ effect of cold exposure - which increases non-shivering thermogenesis (heat production without shivering). This study showed that when exposed to air temperatures of 15-16°C brown fat increased by around 37%.
What about much colder temperatures? Does colder = stronger response?
Our bodies detect temperature through phasic-type thermoreceptors in our skin and other places on the body. These receptors respond rapidly to tiny changes in temperature but adapt and stop firing as the receptor temperature reaches a steady state. They also respond more strongly to a change in stimulus (i.e. larger temperature differences) and temperatures below 15°C are generally perceived to be more painful (the same fibres that mediate the cold sensation are also responsible for the prickling heat pain!). This means that the sensation of cold may feel more intense at lower temperatures.
There is also evidence that there’s a greater release of noradrenaline the lower the temperature, however, as this review shows, it's not 100% conclusive.
As someone who has experienced an ice bath in the Spanish summer sun, a winter swim in the Irish Sea, a dip in a fast-flowing, icy Polish waterfall and everything in between, I certainly agree that we perceive cold differently based on water temperature, but this too is relative - and from my experience also influenced by diverse external factors including mood, setting and of course outside air temperature.
Is colder water a better experience? Should you be aiming for as cold as possible?
In my opinion not necessarily. Each temperature gradient, like the location you’re at or the headspace you find yourself in, provides its own unique learning opportunity. It’s up to us to uncover and connect with what the lesson is.
One question I’m frequently asked is “How long should I stay in the ice bath?”. My answer is always “When you no longer feel the need to get out!”
(A big thank you to fellow Wim Hof Method instructor Bart Biermans for sharing this excellent response.)
So, how much of an influence does exposure time play? This long-term study compared 20 seconds of cold water immersion at 4.4°C versus 2 minutes of whole body cryotherapy at -110°C and found that plasma noradrenaline levels increased 200-300% in both groups, making them more or less identical.
However, like temperature, this assumes that increasing your noradrenaline levels is the primary aim, which misses other key reasons to train cold exposure like controlling your stress response and learning to shift your mental state.
The cold is a powerful force and triggers a stress response in the body (the fight-or-flight response mentioned earlier). By learning to get your body’s reaction to the cold under control, by becoming comfortable in the stressful situation and by practicing shifting your mental state from fight-or-flight to calm and controlled, you’re using the cold as a hormetic stressor - a “what doesn’t kill you makes you stronger” type of stress, to improve your overall stress tolerance and build resilience.
How long this takes varies from person to person and from day to day (face it, some days are going to suck), so there’s no perfect time to spend in an ice bath.
As a guide happy hormones kick in around 90 seconds and our thermoreceptors begin to settle down after around 2 minutes in an ice bath.
I’ve spent both 1 minute and 10 minutes in the same icy river. Was the longer dip better? Yes, but not because it was longer. I got more out of it because I was more connected to my body, to my mind and to the moment, and that’s the takeaway here… focus on the connection instead of on the clock.
While it was a draw between Team Cold Water Immersion and Team Cryotherapy when it came to noradrenaline levels and exposure times, they’re not created equal.
In her paper ‘Cold Shocking the Body’, Dr Rhonda Patrick discusses three factors that differentiate the two methods:
Thermal conductivity (how well heat is extracted from the body)
How much of the body is exposed to the cold (surface area)
Ice has greatest capability to extract heat from the body, giving cold water immersion the edge over cryotherapy which uses only air (the least heat conductive). The second point depends on how the cold water immersion is done - a full body immersion will lower body temperature more than just legs alone - so cryotherapy, which exposes the entire body to the cold, may have a slight edge. For the third factor, the difference between your body temperature and the method being used to extract the heat from your body, cryotherapy wins (temperatures can be as low as -178°C).
However, as Dr Patrick also points out, people can stay submerged in cold water for a much longer period of time, which may have a more robust effect (the study showing the 5 fold increase in noradrenaline levels had participants in 14°C water for one hour).
So who wins? Whichever one you can do consistently.
Personally I find cryother