Is it really true that cold showers are good for you?

What is the scientific evidence for the physical and mental health benefits of taking cold showers? Breathe magazine writer and family physician Courtney Manser weighs up the research.

WORDS: Courtney Manser

Do cold showers improve mental health?

In theory, exposure to cold can increase the neurotransmitters in the brain that are known to improve mood, such as dopamine, serotonin and norepinephrine. Research as to whether this translates into reality, however, is limited.

One very small study, published in the journal Medical Hypothesis, showed improved mood after cold showers in people with depressive symptoms below the threshold to diagnose depression. But precisely because the study was small and involved a statistically insignificant number of people, it can’t be considered conclusive. Ultimately, more research needs to be done to prove whether this effect is true.

Does taking cold showers boost your immunity?

This hypothesis has the best evidence to support its claim. A randomised, controlled trial, completed in 2015 in the Netherlands, separated individuals into two groups – one took cold showers for 30 consecutive days, while the control group didn’t. The group that participated in daily cold showers showed a 29 per cent reduction in self-reported sickness absence from work.

Although this is promising, it’s only one study and, unfortunately, isn’t without its flaws. Illness was self-reported, as was the completion of daily cold showers. The study included only people between the ages of 18 and 65, without any serious medical issues, which means there’s no telling how immunocompromised individuals would be affected. It was promising, however, and will hopefully encourage more research.

Are cold showers good for your hair?

Unfortunately, this one isn’t backed by evidence because there haven’t been any reliable studies to challenge the claim. In fact, extreme temperature may cause damage to your hair. Cold showers can cause the blood flow to the scalp to decrease temporarily and therefore have a potentially negative impact on hair growth at the root. But this is still only a theory and not proven one way or the other. At the very least, cold showers don’t appear to help the appearance or growth of hair.

Can cold showers help with weight loss?

Cold-water immersion may boost metabolism and lead to weight loss, but the evidence is lacking because of an absence of good-quality research. Just last year, a review study was published in the International Journal of Circumpolar Health that tried to narrow down the

evidence. The studies reviewed cold-water immersion, but some had flaws, such as a focus on one gender or differences in exposure temperature.

Cold-water immersion does seem to decrease or alter adipose tissue, but it’s unclear as to what extent. The review study’s author admits that more research is needed to make an accurate conclusion. Ultimately, most experts agree that if you’re looking to lose weight, exercise and a healthy diet will go a lot further than shivering off the pounds.

Can cold showers improve heart health?

This one is tricky. Exposure to cold has been proven to stimulate norepinephrine production and the sympathetic nervous system’s fight-or-flight response. In theory, this works in a similar way to exercise, causing vasoconstriction to the extremities to improve blood flow to vital organs.

Unfortunately, there isn’t enough evidence to support the theory that cold showers offer cardiovascular protection. A review published in the International Journal of Circumpolar Health claimed that cold-water immersion may improve heart health, but also noted that people who made a habit of it may be healthier to begin with.

Conversely, and importantly, a sudden shock to the cardiovascular system from exposure to cold water can lead to a heart attack or a cardiovascular event. The American Heart Association cautions against cold-water immersion in anyone with a history of cardiac problems.

Do cold showers speed up muscle recovery after exercise?

Cold showers may reduce muscle fatigue after exercise. According to a systematic review in the Journal of Strength and Conditioning Research, exposure to cold water following exposure to hot water, or cold-water immersion on its own, can improve symptoms of muscle fatigue after exercise. The downside? Any study that relies on perception, rather than something tangible or that can be measured, is naturally flawed.

So, while cold showers may help prevent illness, improve mood, energy and muscle fatigue after exercise and play a part in maintaining a healthy weight, more studies are needed to come to any definitive conclusions. What is known is that gradual introduction to cold water to build tolerance is less risky than sudden cold-water immersion.

If you think you want to try it out for yourself and are unsure about your cardiac risk factors, you may want to speak to your GP first. Cold showers may not fix all your problems, but that sudden rush of energy is sometimes reason enough to give them a try.