If it seems like you’re hearing about ice baths everywhere, you’re not the only one. Google trends data indicates that searches for ‘ice bath’ have doubled since October last year. But is the hype justified? There are several popular claims, so let’s break down a few.
Claim 1) Ice baths increase brain dopamine by 500%
This statistic has been doing the rounds on the internet for a few months now. It sounds great, doesn’t it! There is some truth to it. The claims are based on a study which was conducted back in the year 2000 in ten young men. It’s a good study, but there are a few points which are worth bearing in mind.
First, the study did not measure dopamine in the brain directly. This is difficult to do in humans without killing them. Understandably, the researchers used circulating levels in blood plasma as a proxy.
Perhaps most importantly, in my view, the dopamine boost associated with an ice bath is not unique to this method. Any event which increases sympathetic nervous system activity, such as stress, exercise, or even standing up, increases plasma dopamine concentration. Running cold water over your head is a good example, but you could also just go for a jog or some other form of exercise you enjoy and likely get a similar effect if you would prefer that.
Claim 2) Ice baths increase brown fat (known as Brown Adipose Tissue, or BAT) activation, which increases weight loss.
A proven cellular mechanism indicates that ice baths can trigger increased BAT activity. See these two studies, for example. However, adults have tiny amounts of BAT. Also, eating drive increases, & energy expenditure decreases following cold exposure. Together, this means that while the claims concerning activity are true, there is little practical effect.
However, while the increased activity of BAT might not be most important mechanism, there is still more to be understood about the relationship between cold exposure, body composition and weight loss. For example, in a new study 49 (male and female) soldiers aged 19-30 were assigned to a control or intervention group featuring cold exposure for 8 weeks, in outdoor and indoor environments (1X per week cold immersion & 5X per week cold showers). In men, there was a statistically reduction in waist circumference (1.3%, p=0.029) and abdominal fat (5.5%, p=0.042).
Claim 3) Ice baths improve recovery.
It’s true that ice baths speed up post-exercise recovery. However, this comes at the cost of reduced adaptation to training, as the soreness & inflammation, which ice baths reduce, are actually and an important stimulus for improvements in muscle strength, power, & size. Consequently, ice baths could be a helpful tool in the heat of competition, but if your aim is to maximise the benefits from training, you might want to reconsider the cold plunge after training.
Claim 4) Ice baths improve cognitive performance?
A recent review concluded that cold exposure impairs performance during exposure & for a short period afterwards.
Claim 5) Ice baths make you feel good.
A small study does indicate that cold water exposure improved mood. So, if you really enjoy your ice bath, good for you!
Overall, my reading of the evidence is that voluntary cold exposure has some health benefits. However, the relationships between ice baths and the benefits we’ve observed might not be causal, and more research is needed. Other factors linked to cold exposure, such as breathing techniques, social interactions, & being in a natural environment, may explain the benefits.
If you don’t have a health condition that makes it risky, my view is that cold exposure may be worth trying IF you enjoy it, but it’s not necessarily the elixir of life it’s made out to be.