healthHealth and Medicinehealthhealth

Yes, There's A Scientifically "Best" Way To Have A Bath. This Is It

Hot tub party everyone! It's for science!


Dr. Katie Spalding


Dr. Katie Spalding

Freelance Writer

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer

Woman relaxing in the bath

How long should you stay in the tub? Science has the answer.

Image credit: Maridav/

We all love a long, hot soak in the tub to help relieve the stresses of the day. Unfortunately, it turns out the latest thing to add to that stress… might actually be the bath itself.

That’s right: according to the internet (which is never wrong), taking a bath is bad for you. Can it really be true?


Well – kind of, yeah. But it’s not all bad news, we promise.

What’s the claim?

Spend long enough online, and you’ll find someone saying just about anything is bad for you – often with pretty spurious reasoning to back it up. 

In the case of baths, however, the claim is pretty specific: indulging in a long, hot bath can cause skin irritation and inflammation, and should be avoided. In fact, some people go so far as to say that we should do the exact opposite, and keep our baths and showers icy-cold for maximum health benefits.

But how can that gel with how good a lovely soak in the bath feels? Or the long history of people enjoying baths – surely all Romans didn’t have terrible acne and rashes all the time? 


More to the point, how can it gel with those other claims you’ve seen around – the ones saying that sitting in a tub of hot water for hours actually has multiple health benefits, and is basically the equivalent of a workout?

It’s all pretty confusing. So what’s the truth?

Baths: the good

There’s a reason most of us like baths so much, and it’s not because they make us feel worse. 

“Taking a bath has great physical and mental health benefits,” said Cleveland Clinic family medicine provider Dr Amy Zack. “Soaking in a tub is something many people have access to but don’t take advantage of enough. But it can be beneficial for a lot of people.”


Indeed, evidence has shown that people who take baths are likely to be less angry, less stressed, less anxious, and less depressed than those who only shower. Frequent baths make you feel healthier and sleep better, and, pretty much by definition, they get us clean.

“Bathing cleans your skin, helping you avoid irritation, inflammation and sores caused by dead skin cell accumulation,” Dr Zack explained. “It can also help you clear away the bacterial and fungal load from contact in your environment. As that accumulates, it increases your risk of infection.”  

But it turns out their benefits may go even deeper. While balneotherapy – aka hydrotherapy, aka sitting in a bath for medicinal purposes – has been around for centuries, its scientific credentials have traditionally been seen as about the equivalent as, say, homeopathy. There’s a good reason for that: despite what Dr Kellogg (yes, the cornflake masturbation guy) may tell you, no amount of baths will cure your diabetes or infertility.

But recent research does suggest that a nice hot dunk actually can have some therapeutic effects. “In the last few decades evidence has been growing,” wrote Charles Steward, a PhD candidate at Coventry University in the Centre for Sport, Exercise and Life Sciences, “and today we know that regular bathing in a sauna or hot tub can help reduce the risk of cardiovascular disease – and may well have wider health benefits too.”


How can a hot bath – or, more likely, a hot tub or sauna – help your heart health? It may be the effect of a confounding variable, Steward cautioned – but there are potential biological explanations too. “On the basis that cardiovascular disease is primarily caused by diseases of the artery, it’s probable that improvements in blood vessel health – which we now know occurs with regular heat therapy – is a large reason for the reduction in the risk of cardiovascular disease,” he explained.

Other studies have linked frequent, hour-long hot tub sessions to a reduction in both blood glucose levels and a wide range of symptoms associated with polycystic ovary syndrome. So, uh… guess we owe you an apology on that one, Kellogg.

Baths: the bad

Here’s the thing. There’s a pretty big caveat to all those bath benefits, and it’s that, in practice, you’re not going to see them without some specialist equipment. 

“I want to point out that the water temperatures and lengths of time mentioned above are not representative of your everyday bath,” Steward noted. “In your conventional bath tub, the temperature will gradually drop… when using my hot tub in the lab, I must carefully monitor my volunteers for safety reasons: I measure their core body temperature (using a rectal thermometer), blood pressure and constantly check in with how comfortable they are with the heat of the water.”


Since the presence of anything starting with the word “rectal” is likely to reduce the whole stress-relieving, meditative aspect of your me-time, is there any benefit to having just a regular hot bath?

Well, possibly – but unfortunately, it’ll also come with some real downsides, particularly for your skin. 

“Hot water can be abrasive, stripping the skin of its natural oils, which leaves it dehydrated and dull-looking,” Dr Stacy Chimento, board-certified dermatologist at Riverchase Dermatology in Miami Beach, Florida, told Well + Good. “If you get the water on your face as well, this can cause acne flare-ups, breakouts, and skin irritation.” 

You can think of the outermost layer of skin, the epidermis, like a knife covered in a layer of butter, according to Dr Melissa Piliang, a dermatologist with the Cleveland Clinic: under cold water, the fatty lipid layer that protects our skin holds fast – but hot water makes it melt away.


That’s bad news, because this layer “is what keeps bad water and germs out and good water in, and keeps our skin moisturized,” Piliang told the Wall Street Journal. Our bodies will replenish that lipid layer, but it takes longer the older we get – and you can’t even speed the process up using commercial moisturizers, she cautioned. 

The optimum bath: 15 minutes and 44°C

So, is there any way to balance the self-care of a hot soak with the skin care of… well, not doing that? Apparently, yes, there is – and it’s surprisingly exact.

First, the length of time you spend in the tub: “When taking a bath, you should try to limit it to 15 minutes,” Chimento told Well + Good. “Anything longer than that will begin to strip the skin of its natural oils, leading to inflammation and irritation.”

That’s a bit of a shame, because according to a recent survey by UK bathroom retailer Victorian Plumbing, 21 minutes is the ideal length for relaxation purposes. Fifteen minutes is also likely shorter than you currently spend in the tub, which means cutting down on those lovely sudsy seconds.


Secondly, you’re going to want to make sure the water isn’t too hot. Chimento advises keeping the water between 37°C to 43°C (100°F to 110°F) – warm, but not uncomfortably so – while Piliang gets even more granular: 44.4°C (112°F) is perfect, she says, “though you’d have to put a thermometer under the spigot to get an exact reading.”

Oh – and as for those sadists who tell you your baths and showers should be ice cold for maximum health benefits? Don’t listen to them.

After all, the experts don’t. “If you are someone who thinks a cold shower… is as awakening in the morning as a cup of coffee, I don’t think taking one is dangerous,” Piliang said. “It just depends on how much agony you want.”


healthHealth and Medicinehealthhealth
  • tag
  • skin,

  • health,

  • bath,

  • relaxation