Wellness benefits of contrast bathing

Warm and cold therapy is an established protocol amongst both natural medicine cultures and high-level athletic performance but in recent years the biohacking community have adopted similar techniques for their own mental and physical health benefits. 

The ‘contrast bathing’ version of such hydrotherapy deliberately alternates intense warm and cold experiences in the hope of reducing post-exercise recovery time and muscle soreness on one level while improving cognitive function and sleep quality on the other.  

This type of concept also fits neatly into Biofit’s belief in respectfully harnessing nature for physical and mental wellness; so how does it all work and how can you try it for yourself?

what is contrast bathing?

Also known as thermal cycling, in essence contrast bathing consists of at least one hot and one cold bath, shower or other experiential full-body immersion. Advanced, inner-city variations on the theme might involve an infrared sauna, ice bath or cryotherapy for example.

If you have access to a sauna in your gym or a hot bath home, a nearby lake, river or beach perhaps, or simply live somewhere with regular snowfall, you should be half way there already! In fact, I would argue there are additional psychological benefits to be had from integrating exposure to nature into the mix as well, more on that later though…

what is the science behind contrast bathing?

Scientists believe that successive exposure to heat and cold increases blood flow to our muscles which reduces swelling and inflammation, helping to clear lactate from the system, an obvious marker for muscle fatigue.[3] 

Additionally, temperature stresses trigger extra nerve activity, crowding out pain signals[4] which in turn has a positive effect on the immune system.[5] 

Research also suggests that daily cold stress, such as a cold shower in the morning say, can lead to an increase in immune cells and protects against infection.[6] Again, our own anecdotal evidence here suggests some light exercise in the morning such as stretching or a brisk walk, followed by a cold shower is a safe bet for supercharging your morning!

what protocol should you follow?

There is no one definitive protocol for contrast bathing; coaches, sports physicians and enthusiasts all have their favourite techniques but, as a general rule, you’re looking to hit between 10-15°C for the ‘cold’ and 38-40°C for the ‘hot’ part.  

In lay terms, you should be looking for a moderate discomfort level before stepping out, really feeling the heat or cold making an impact on your body temperature. Much of this is mental of course but without some degree of stress being imposed on the body, the effects will be inherently limited.

how long should a contrast bathing session last? 

Recommended times tend to be longer for the heat sessions, 10 to 15 minutes say, and shorter for the cold, perhaps 1 to 3 minutes. A total duration of 15 to 20 minutes per cycle is therefore a good guideline.[1] One cycle is good, two to three cycles are better, if time allows. Just don’t go overboard! Listen to your body and don’t try to be a hero if are new to this. Over time, you will grow accustomed to it and you can start to play with your limits but go slow.

is thermal cycling helpful for post-exercise recovery?

High-intensity and long-distance exercise are especially tough on the body, so for those who train hard or go long on a regular basis the aches, pains and some degree of general fatigue becomes unavoidable, unless you happen to be under-18! 

For the greatest benefit in muscle recovery, scientific research suggests that contrast bathing should take place as soon as possible after working out.[2] Imagine pro footballers jumping from ice bath to hot shower or sauna after a game.

I would assume that most people are not pro athletes however and therefore may  not even have time for their full training session, let alone training and recovery treatments in quick succession. Luckily, anecdotal evidence indicates that it is also beneficial to drop into an ‘active recovery’ day.

biofit’s approach to rest & recovery

After nearly 25 years of training under my belt, and a plan to continue for at least 25 more (!), I’ve come to appreciate the value in deliberately scheduling a day of R&R in my training schedule every four weeks or so.

This typically involves some combination of a nature hike, deep-tissue massage, mobility session, self-myofascial release (SMFR), a short afternoon siesta (ideally in the sun for added Vitamin D) and a contrast bathing experience. 

My diet is nicely dialed in nowadays but on these R&R days I will be extra diligent about doubling down on the healthy fats, lean protein and cruciferous vegetables… as well as copious amounts of water to flush out the system and no caffeine to encourage any extra naps that might be on the cards!

It’s about doing everything possible to give the body a chance to grow back stronger and tougher than before. Intermittent fasting can wait for another day!

how much difference does it make?

Current evidence suggests that contrast bathing is better for recovery than simply resting (passive recovery) after exercise and is on par with other interventions like compression, active recovery  (see previous para) and stretching.[3] My approach at age 37 is to throw everything at the wall; and take no prisoners!

why incorporate nature as well?

Scientific research studies that specifically isolate this particular variable within the thermal cycling experience are hard to track down but we do know that acute temperature stresses release beta-endorphin, a natural opioid which lifts the mood, without any side effects.[6] 

Exposure to nature has been shown time and again to have a positive impact on mood, reducing stress levels and creating feelings of vitality (see our own research studies from 2017 & 2018 here); outdoor contrast bathing of any variety simply layers the same benefits on top of those related to the physical exposure to hot and cold experiences.

Does it double the impact? Probably not but we might say it extends the range of benefits on offer from that one combined experience. 

can thermal cycling improve cognitive function?

Biohackers are onto a good thing here. Thermal cycling releases cortisol, noradrenaline and adrenocorticotropic hormone (ACTH) into the bloodstream. These and other stress hormones increase alertness, focus and energy rather like an all-natural alternative to espresso [6],[5]. 

A word of warning though, personal experience suggests there is a thin line between coming out the other side with a clear head and hitting an entirely pleasant but all-consuming energy crash directly afterwards, so experiment on yourself to see what works for you.

cold tolerance and outdoor activities 

Finally, this may be stating the obvious but hot showers are a modern invention, not an evolutionary necessity - quite the opposite, otherwise we wouldn’t be where we are today at the top of the food chain. 

Introducing a small dose of nature-inspired ‘adversity' into a complete training routine is therefore both concordant with our evolutionary history and comes with a plethora of proven health benefits.[6] More generally though, cold-tolerance helps you when active outdoors, whether it be  surfing or skiing. So, what are you waiting for?

References

[1] https://www.ncbi.nlm.nih.gov/pubmed/19083715

[2] https://www.ncbi.nlm.nih.gov/pubmed/23743793

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3633882/

[4] https://www.ncbi.nlm.nih.gov/pubmed/28150163

[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4183517/

[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049052/