Researchers found that the perfect time to take a bath to cool down the core body temperature in order to improve sleep quality is about 90 minutes before going to bed.
Sleep is sacred. Most of us struggle to get five hours of proper sleep, let alone eight. Insomnia is real, people, and it's a problem that most of us face. There are a lot of reasons why we lose sleep, the most common one being stress and anxiety. There are pills to help you get some sleep, but now, there seems to be a more effective method, one that takes nothing, and lets you relax at the same time. Biomedical engineers at The University of Texas at Austin looked at thousands of studies linking water-based passive body heating, or bathing and showering with warm/hot water with better sleep quality. Specifically, researchers in the Cockrell School of Engineering found that taking a bath in water at temperatures of 104 to 109 degrees Fahrenheit (40 to 43 degrees Celsius) one to two hours before bedtime can drastically improve your sleep reports Science Daily.
Shahab Haghayegh, a Ph.D. candidate in the Department of Biomedical Engineering and lead author on the paper stated, "When we looked through all known studies, we noticed significant disparities in terms of the approaches and findings. The only way to make an accurate determination of whether sleep can in fact be improved was to combine all the past data and look at it through a new lens."
Explaining their method, a paper was recently published in the journal Sleep Medicine Reviews. In addition, a collaboration with UT Health Science Center at Houston and the University of Southern California took place. The UT researchers reviewed 5,322 studies. The researchers went through these studies to extract relevant information on the effects of water-based passive body heating on a number of sleep-related conditions.
The conditions they explored were: sleep onset latency (the length of time it takes to accomplish the transition from full wakefulness to sleep); total sleep time; sleep efficiency (the amount of time spent asleep relative to the total amount of time spent in bed intended for sleep); and subjective sleep quality. Once this was done, meta-analytical tools were then used to assess the consistency between relevant studies.
This showed that the optimum temperature of 104 to 109 degrees Fahrenheit improved overall sleep quality. When the bath was scheduled 1-2 hours before the usual sleep time, the researchers also found that bathing can also increase the speed of falling asleep by an average of 10 minutes. There is a lot of science to back up the link between water-based body heating and improved sleep.
It is a known fact that our body’s core temperature and our sleep are both regulated by a circadian clock that is located within the brain’s hypothalamus which drives the 24-hour patterns of several different biological processes, including sleep and wakefulness. Body temperature was noted to display a circadian cycle, which meant that it was 2 to 3 degrees Fahrenheit higher in the late afternoon/early evening than during sleep when it is the lowest.
Typically, an average person's circadian cycle is marked by a reduction in core body temperature of about 0.5 to 1º F around an hour before usual sleep time. Between the middle and later period of nighttime sleep, it drops to its lowest level. When the temperature slowly begins to rise, it works as a kind of a biological alarm clock wake-up signal. This temperature cycle leads to the sleep cycle and plays an important role in achieving rapid sleep onset and high-efficiency sleep.
Thus, researchers found that the perfect time to take a bath to cool down the core body temperature in order to improve sleep quality is about 90 minutes before going to bed. The body's thermoregulatory system is stimulated by warm baths and showers. This, in turn, leads to an increase in blood circulation from the body's internal core to the ends of the hands and feet, which help in the efficient removal of body heat and a decline in body temperature. So, if you're looking to get some good quality zzz's, all you need to do is take a long shower at the right time!