Reference; http://seino-1987.jp/blog/5955.html
Modified and translated by CFJA
Length of time for taking a bath.
How long do you usually take a bath? 20 to 30 minutes of showering and soaking in the bath?
Some people take a bath for more than an hour, but those who take such long baths all complaint of physical problems. People who take long bath claims that since their body gets cold easily, taking a long bath helps to warm up their body.
The temperature on the surface of our skin is about 36°C. The temperature inside our body is around 37°C. If you take a bath at 38°C or higher, the water will feel hot at first, but in a couple of minutes, it will feel just right. This is because the body takes the heat away from the water – in just a matter of minutes. After a while, the water will then start to feel lukewarm. That’s because the skin pores open up and the water will take away heat from the body. Most people will then reheat or add hot water. Repeating this action for one or two hours will only make your body get tired.
But if you want to just warm up your body, two or three minutes of bathing is enough. It might feel short for those that want to relax in the bathtub, this is just a matter of finding the balance between your mental satisfaction and body needs, and body. Taking a longer bath can be a problem if you lack energy but it should not be a problem if you have enough energy. Of course, there are some other factors that might come into play, but many people who have spent more than half an hour in the bathtub are very likely to complain of some kind of problem with their bodies.