- Positive short term effects which kick start the day. Helpful for those that struggle to get going. Might be helpful in cutting down on caffeine.
- Strong environmental trigger to help your natural circadian rhythm put you to sleep.
- No evidence of downside, except for people already at high risk of heart attack or stroke, or those in the grips of a fever.
- Enough evidence across enough health benefits to make it worth a try, and to justify further research.
My research has definitely given me some expertise (which is what this is all about), but it’s a very complicated idea which requires deep knowledge of biology, and will require rigorous research through scientific journals to really be sure about individual claims. I do at least feel like a have a decent enough grasp of the arguments that I’m confident I’m not blindly following a fad.
I’m very sure this practice is doing me good, on balance, in lots of unimportant ways that nevertheless add up, making for a compelling cost/benefit analysis. It’s low risk (for me, given my general state of health), offers short term benefits (invigoration, energisation, and a dose of EXTREME mindfulness), and might proffer longer term benefits too.
So, I’d encourage you to give it a go!
Cold Water Therapy – Overview
Cold water therapy is pretty much as billed. The fundamental claim is that exposure to extreme cold has all sorts of health benefits. The most accessible and hence most discussed means of cold water therapy is a cold shower, but alternatives include an ice bath (a bunch of ice dumped in a bath of cold water), and even cryo-chambers (special chambers which expose the body (or parts of the body) to EXTREME low temperatures – look to Joe Rogan for an advocate).
Further to this there are cold treatments with very specific medical uses, such as cold caps being used to preserve hair during chemotherapy; and cryosurgery, in which cold is used to target and destroy tissue – but that’s not what I’m trying to learn about at the moment.
My personal experience includes regular cold showers and occasional cold baths (mostly limited by the opportunity to leap into a cold plunge pool at a spa).
As with so many trending health interventions like this, it’s not hard to find lots of “[n – n ranging from 5 to 17 in my search] health benefits of cold showers” style articles. These range from somewhat serious health and well-being blogs, to click-bait-y superficial pieces.
Across the first page of Google results I turned up claims that cold therapy (in rough frequency order):
- promotes healthy skin and hair;
- speeds muscle recovery;
- increases alertness/focus;
- improves circulation;
- aids weight loss;
- offers stress relief;
- strengthens immunity;
- relieves depression;
- increases fertility;
- aids sleep;
- increases testosterone;
- builds will power;
- increases energy; and,
- improves mood.
And, on the risk side:
- increases heart attack risk;
- increases stroke risk; and,
- can exacerbate fevers.
I’ll do away with these risks right now on the basis that these all exacerbate preexisting conditions. It’s probably advisable to avoid (or consult with a doctor) cold therapy if you are already at high risk of heart attack or have hypertension, but for normal healthy individuals it feels like a low-risk activity.
Looking into these claims, I think they can usefully be grouped. Ranked by importance (to me) and sureness (combination of how well I think I understand the claim, and how spurious I think it is, given that level of understanding), these groups are:
- exposure to cold makes your blood rush to your core;
- exposure to cold has mental benefits;
- exposure to cold aids weight loss; and
- cold showers are better than hot baths for your skin, hair and (male) fertility.
Exposure to cold makes your blood rush to your core
Supposedly improving circulation, enhancing immunity, unblocking arteries, strengthening the heart, and aiding sleep.
I’m very sure that exposure to cold has an effect on circulation. It’s pretty uncontroversial that in an attempt to regulate the body’s core temperature at around 37 degrees Celsius, blood will be pushed near the surface to help radiate heat if it gets too hot, and drawn into the core (around the organs) if it gets too cold. Does that actually do any good though, beyond homeostasis?
The claim here is that this increase in blood flow increases white blood cell concentrations, which will increase immunity. There seems to be a lot of heat and not a lot of light around this subject, but perhaps more rigorous research on proper clinical trials will turn up something. Seems to me that it is at best a peripheral benefit. If this were the only benefit, I’m not sure that putting yourself through a cold shower is the most sensible way to increase circulation. I think I’d probably go for a jog instead.
Unblocking arteries and strengthening the heart
As above, the idea here is that the shock to the system triggers the “fight or flight” response, which kick starts the heart, giving it a workout and unblocking arteries.
Again, it doesn’t feel like the most sensible way to increase your heart rate, especially if you have blocked arteries. A brisk walk with some weights around your wrists and ankles would probably be a safer and more pleasant way to make progress here.
This alone is the reason that I characterised this group as “important”. I’ll probably cover this in detail in a separate post at some point, but I am increasingly convinced that sleep is a panacea. I encourage you to read Why We Sleep by Matthew Walker in the meantime.
The idea here is that temperature, along with blue light exposure (I’ll probably write about this, too), is an environmental signal (known, delightfully, as zeitgebers – “time givers” in German) for your circadian rhythm. The circadian rhythm is a natural clock which ticks away in all of us, and tells our body when it should be going to sleep, and when it should be waking up. It has an active function at either end of the day, regulating melatonin, which controls our level of drowsiness.
Although less severe regulation of the environment (reducing the temperature in the bedroom) will have the same effect, my own personal experience favours the cold shower approach for two reasons:
- in my experience, and particularly if following a sauna, the sharp drop in temperature has a dramatic relaxing effect on me about ten minutes after the initial adrenaline spike has worn off; and,
- i share a bedroom with my wife, and she’s not as convinced about the benefits of a cold bedroom…
The sleep thing is reason enough for me. The rest is plausible, and serves as a nice cherry on top.
Exposure to cold has mental benefits
The core claim here is that doses of exposure to extreme cold make you more alert, more focused, relieves stress and depression, improves mood, increases energy, and even builds will power. Wow.
There is, again, as I would put it, a lot of heat and not a lot of light around these claims. You don’t have to look far for talk of uric acid suppression, release of glutathione, and various other antioxidant effects, but my brief research didn’t turn up anything substantive in terms of scientific validation of these claims. That’s certainly not disproof, but I remain unsure about all this.
I am, however, very sure that there is short term relief from these maladies to be offered, and short/medium term boosts of the benefits promised. This sureness come from my direct experience, but also that the arguments seem logically safe.
I am prepared to back these claims:
- The shock of the cold water gets the heart going, and you can’t help but take some very deep breathes. This pushes a great whack of oxygen into your brain, which does a great job of waking you up, and makes you feel energised for at least an hour afterwards.
- It requires extreme focus and will power to stay in the shower for more than a few seconds. The only way I’ve been able to last a minute or more is to focus on slowing the breath down, and relaxing the shoulders. After a while it’s even possible to start to enjoy the feeling by focusing on the invigorating nature of it as opposed to the shock. I’ve been practising mindfulness meditation for some time now (I’ll probably write about that too), and I find this to be an intense grounding experience. It’s very difficult to make the mind wander during a cold shower…
As for mood and depression, I can’t find any evidence that a cold shower does anything more than offer temporary relief. This might be valuable enough in it’s own right but: (a) I know from experience that it’s tough enough to coax a severely depressed person into a warm shower, let alone a cold one; and, (b) I’m not sure how far the effect would extend into the rest of the day.
It’s definitely an invigorating way to get the day started, and there’s at least an hour or so at the beginning of the day in which you feel energised. This is certainly not to be sniffed at, especially if you’re trying to cut down on caffeine consumption.
Exposure to cold aids weight loss
This ranks as important for me, but I remain dubious.
The argument is that brown fat is both consumed and encouraged to develop by sudden (and prolonged) exposure to cold. Whereas white fat is like a long term energy store, brown fat is packed with mitochondria, and is stored closer to the skin surface (mostly around the neck and shoulders for most people) so that it can be quickly burnt if the external temperature drops. Its role is to warm the blood and maintain homeostasis rather than act as energy for muscles as white fat does. It’s a bit like the equivalent of cash, which can be accessed quickly and spent to meet short term needs, as opposed to long term savings tied up in equities (white fat), which are more difficult and expensive to liquidate.
I like the sound of this, and there’s a lot of support from people like Tim Ferris and Max Lugavere, but I’m yet to see any really solid scientific evidence that it will significantly move the needle on weight loss.
Cold showers are better than hot baths for your skin, hair and (male) fertility
Not particularly important to me, and I’m extremely dubious (about the sustained benefit, at least).
The arguments for healthier hair, skin, and improved fertility and testosterone production (in males, obvs) all seem to point to the virtue of cold showers as an alternative to a hot bath, rather than in and of themselves. I think this is specious; I suspect that it’s more about avoiding the extreme hot (which is shown to dry out skin and damage hair, and lower fertility in males) than opting for extreme cold. I suspect most of the benefit would come from a shower which is a smidgen below body temperature.
I do notice that my skin does feel good after a cold shower, but it feels like a temporary effect. As for hair, I can’t say I really pay that much attention. I am aware that there are cold cap treatments being used with some success in chemotherapy as a way to help patients retain hair, but the benefit is all delivered during the treatment, not due to any long term changes. In this treatment the follicles ‘tighten up’, which allows less of the chemotherapy drug into the follicle, which reduces rate of hair loss.
I think the effect is similar on skin and hair in cold showers. Pores and follicles tighten up, which helps keep muck out and helpful oils in. This is a good thing, but the pores will open up again soon after and let the day’s grime in as normal.
Cold showers are a thing for me, for now. I tend to get my cold showers in at two times of the day.
I started off by easing myself into it by gradually turning down the temperature, but I found that just drew out the process, so now I just go for it. I stand entire underneath the shower head, turn the temperature tap all the way down, then let ‘er rip. I stay under the cold stream until I’ve managed to calm my breathing and relax my shoulders, then reach out and twist the temperature knob to just below body temp and enjoy the feeling of the water coming up to temperature whilst I’m under it.
Next I’ll kill the water altogether and lather up (I’ll spare the details). For the rinse, I repeat the previous process, giving me another decent hit. As I’ve grown more used to this process I tend not to increase the temperature for the final rinse. Relief comes from turning off the flow altogether, and I find that towelling off is really invigorating if I’m stepping straight out of cold water.
Three to Four times per week (really only limited by diary) I’ll spend around 15 minutes building up a good sweat in the sauna or hot-tub, and then will run upstairs and straight into a cold shower to rinse off. I’ll only spend about 3 minutes in there, but that’s enough to really knock me out and get me ready for a decent sleep (once the adrenaline has worn off).
The hot-tub or sauna brings the blood to the extremities and skin surface, and then the cold water really cools it down and makes it rush back to the core. The theory is that this is a powerful zeitgeber for the circadian rhythm, which preps your body for sleep. Maybe this is just psychosomatic but, either way, it seems to be working for me.
Next level: I have a plunge pool… It’s currently sitting boxed up in my hallway waiting to be built, but I’m excited about this an an option. The plan is to keep it outside at ambient temperature next to the hot-tub, so I’ll be able to alternate between the two for a hot/cold variation.