Why swapping your shower for a bath is good for your heart

Four in 10 of us never take a bath. Showers are faster and cheaper and our busy lifestyles have put us off them, research suggests. But there’s no denying that a long, hot soak is relaxing and helps us to unwind.

Despite turning our back on them of late, it may be time to rediscover the joys of the simple bath, to benefit body and mind. Research shows they support our hearts in a similar way to exercise, encourage us to nod off faster and markedly reduce our stress levels. Here the experts share the powerful science behind bathing and how to harness it for better health.

For a heart health boost: Take a 30-minute bath at least three times a week

Our bodies are constantly working to maintain a stable internal temperature of about 37 degrees, as this provides the perfect conditions for our organs to work properly and our cells to remain healthy, says Dr Charles Steward, a specialist human studies technician at the University of Nottingham.

When we get into a warm bath, our body senses the hot water and, in a bid to maintain this core temperature, increases the volume and speed of blood flowing to the skin so that excess heat can be lost to the air.

To do this, our heart rate increases and our blood vessels dilate (widen) to increase blood flow, says Dr Christof Leicht, a reader in exercise, health and rehabilitation at Loughborough University. This is why your skin may turn pink in the bath and, about 10 minutes later, you may begin to sweat. As we remain submerged in the bath, these processes fail to cool the body down, but they do benefit our heart health.

Blood pressure drops as our blood flows more easily through dilated vessels and the increase in blood rubbing against our vessel walls, over time, makes them more flexible (a key component of good cardiovascular health).

The temporary increase in blood flow while in the bath also encourages the body to build more capillaries (fine blood vessels that deliver nutrients and oxygen to cells), which can help to decrease blood pressure in the long run.

“These benefits are particularly important as high blood pressure and poor artery function are among the leading causes of strokes and heart attacks,” says Dr Tom Cullen, an assistant professor at Coventry University’s Centre for Physical Activity, Sport and Exercise Sciences. His research has shown that these effects are comparable with exercise.

However, this doesn’t mean you ought to cancel your gym membership in favour of relaxing in the bath.

“Most research suggests that hot baths should complement, not replace, other healthy lifestyle habits such as regular exercise and a balanced diet,” says Steward, who also worked on this study.

“Exercise remains the most effective way to improve overall health, as it provides benefits that heat exposure alone cannot, including building muscle mass through repeated muscle contractions, reducing fat mass through increases in energy expenditure and strengthening bones through weight-bearing activity.”

However, a bath can still play a role in improving your heart health.

“I do believe that some additional heating via hot baths or saunas can be a nice additional healthy activity to improve certain aspects of health, particularly cardiovascular health,” Cullen says.

Steward recommends taking a 39-degree bath for 30 minutes to an hour about three times a week for eight weeks, which should trigger improvements in blood vessel function and a drop in blood pressure.

“If you are happy to stay in for longer than that, then the benefits are likely to be better, but just be careful getting out of the bath as some people can feel a bit lightheaded,” Cullen says.

A hot bath can also contribute to dehydration, which can cause headaches and tiredness, so it’s worth having a glass of water nearby, the experts say.

“It needs to be more than just a bit lukewarm,” Leicht adds. “You should start to sweat a bit and, after 10 or 15 minutes, you should feel like you want to put a limb out of the water. That could be a helpful indicator if you don’t have a thermometer.”

To improve sleep: Take a 15- to 20-minute bath 90 minutes before bed

As well as helping you mentally wind down before bed, baths trigger physical effects that can make it easier to nod off and have a better quality of sleep.

“After you get out of a warm bath, there will be a difference between your skin temperature and your core temperature,” Leicht says. Our skin cools down quickly after being exposed to the air, while our core will remain warmer for longer, he says.

Research has linked this difference between core and skin temperature with better sleep, including falling asleep more quickly and an increase in rapid eye movement (REM) sleep, which is vital for brain function.

“The theory is that the cooling down after a hot bath helps to stimulate melatonin production in the hypothalamus [the part of the brain that regulates sleep cycles],” Cullen says. “Melatonin is the hormone that naturally makes us feel sleepy. It does this because melatonin is typically produced in the evening when our body temperature decreases.”

Studies suggest that taking a 15- to 20-minute bath about 90 minutes before going to bed will trigger these improvements in sleep, says Cullen.

“Another thing,” notes Leicht, “is that a bath just relaxes you, as your blood pressure comes down during a bath and your cortisol may drop as well.”

To reduce stress levels: Take a 15-minute bath when you need a mood boost

The benefits of a warm bath aren’t just physical – they can also improve your mood, research suggests. “In our studies, we have seen reductions in the stress hormone cortisol after a hot bath, which I think is likely to be what is causing the improvement in mood,” Cullen says.

There is also some evidence to suggest that a bath helps the body release feel-good chemicals such as endorphins and dopamine, Steward notes. It can also relax your muscles, leaving you feeling less stressed, he says.

“Some of the effects may be from being in the relaxed environment of a bath,” Leicht says, but studies also show that inflammatory markers (interleukin-6) can come down while submerged in water, which may also play a role in lifting mood.

To feel these effects, the bath can be shorter and cooler than that required for improved heart health, Cullen says. He recommends a 15-minute bath and a temperature of 38 to 39 degrees as often as you like. “I think it would be completely fine to judge for yourself when you have had enough,” he says.

The Telegraph, London

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