Researchers at the University of Texas at Austin in the US have found that the optimal timing of bathing for cooling down of core body temperature in order to get a better night's sleep is about 90 minutes before going to bed.
According to the study published in the journal Sleep Medicine Reviews, bathing one to two hours before bedtime in warm water about 41 degrees celsius can significantly improve your sleep.
They assessed the consistency between relevant studies and showed that an optimum temperature of between 104 and 109 degrees Fahrenheit (40 to 43 degrees Celsius) improved overall sleep quality. When scheduled one to two hours before bedtime, it can also hasten the speed of falling asleep by an average of 10 minutes,
Much of the science to support links between water-based body heating and improved sleep is already well-established, the researchers said.
Sleep and our body's core temperature are regulated by a circadian clock located within the brain's hypothalamus that drives the 24-hour patterns of many biological processes, including sleep and wakefulness. Body temperature, which is involved in the regulation of the sleep/wake cycle, exhibits a circadian cycle, being two to three degrees Fahrenheit higher in the late afternoon/early evening than during sleep, when it is the lowest.
If baths are taken at the right biological time—1 to 2 hours before bedtime—they will aid the natural circadian process and increase one's chances of not only falling asleep quickly but also of experiencing better quality sleep, researchers said after reviewing 5,322 studies.
The average person's circadian cycle is characterised by a reduction in core body temperature of about 0.5 to 1 F around an hour before usual sleep time, dropping to its lowest level between the middle and later span of nighttime sleep, according to the researchers. It then begins to rise, acting as a kind of a biological alarm clock wake-up signal. The temperature cycle leads the sleep cycle and is an essential factor in achieving rapid sleep onset and high efficiency sleep.
Warm baths and showers stimulate the body's thermoregulatory system, causing a marked increase in the circulation of blood from the internal core of the body to the peripheral sites of the hands and feet, resulting in efficient removal of body heat and decline in body temperature.
(With inputs from PTI)