Researchers may have found a way for people to sleep better. The researchers analyzed thousands of studies linking water-based passive body heat, or bathing and showering with warm/hot water, with improved sleep quality. The researchers found that taking a bath or shower in water at about 40-43 degrees Celsius 1-2 hours before going to bed can significantly improve your sleep. It can also speed up the speed of falling asleep by an average of 10 minutes.
Body temperature, which is involved in the regulation of the sleep/wake cycle, exhibits a circadian cycle, which is slightly higher in the late afternoon/early evening than during sleep, when it is lowest. The average person's circadian cycle is characterized by a drop in core body temperature around an hour before usual sleep time, falling to its lowest level between the middle and later periods of nocturnal sleep. It then starts to rise and acts as a sort of alarm signal from a biological alarm clock. The temperature cycle guides the sleep cycle and is an essential factor in achieving fast sleep and high-efficiency sleep.
The researchers found the optimal timing of baths to cool down the core body temperature to improve sleep quality about 90 minutes before going to bed. Warm baths and showers stimulate the body's thermoregulatory system and cause a marked increase in blood circulation from the internal core of the body to the peripheral sites of the hands and feet, resulting in efficient dissipation of body heat and a decrease in body temperature . Therefore, if baths are taken at the correct biological time – 1-2 hours before bedtime – they will promote the natural circadian process and increase the chances of not only falling asleep quickly, but also experiencing better quality sleep.
