New study shows having a shower or bath ninety minutes prior to bedtime cures insomnia and improves quality of sleep
Having a shower or a bath ninety minutes before sleeping, in water that is between 40 to 42.7 degrees Celsius will not only help one to get to sleep but will also ensure that the quality of sleep is optimal, according to results of a study done by biomedical engineers at the University of Texas at Austin.
By utilizing a process of Systematic review protocols, a method used to search for and analyze relevant data, the researchers analyzed more than 5,322 past studies covering a range of topics with regards to water-based passive body heating and ways to improve sleep quality. The team was able extract pertinent information from studies meeting predefined inclusion and exclusion criteria to explore the effects of water-based passive body heating on a number of sleep-related conditions: 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.
Shahab Haghayegh, a PhD candidate and lead author commented in a phone interview with Thailand Medical News "When we looked through all past studies, we noticed interesting 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 perspective."
Meta-analysis tools revealed that an optimum temperature of between 40 and 42.7 degrees Celsius improved overall sleep quality. When scheduled approximately 90 minutes before bedtime, it can also increase the speed of falling asleep by an average of 10 minutes.
Much of the medical data to support links between water-based body heating and improved sleep is already proven and documented. For instance, it is understood that both sleep and our body's core temperature are regulated by a circadian clock located within the brain's hypothalamus region and that it drives the 24-hour patterns of many biological actions, including sleep and wakefulness. Body temperature, which is involved in the regulation of the sleep/wake cycle, exhibits a circadian cycle, being 0.5-1.5 degrees Celsius higher in the late afternoon/early evening than during sleep, when it is the lowest. The average person's circadian cycle is characterized by a reduction in core body temperature of about 0.25 to 0.5 degrees Celsius around an hour before normal sleep time, plunging to its lowest level around the middle and later span of nighttime sleep. It begins to rise again, acting as a kind of a biological alarm clock wake-up signal. The temperature cycle leads the sleep cycle and is a critical factor in obtaining rapid sleep onset and high efficiency sleep.
The team discovered the optimal timing of bathing for cooling down of core body temperature in order to improve sleep quality is about 90 minutes before going to bed. Warm baths and showers stimulate the body's thermoregulatory system, creating 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 removal of body heat and decline in body temperature. Therefore, if baths are taken at the right biological time,90 minutes before bedtime, they will help the natural circadian process. It will result in a higher percentage of falling asleep and also receiving optimal sleep quality.
The team is planning to design a commercially viable bed system with UT-patented Selective Thermal Stimulation technology, such that it allows thermoregulatory function to be manipulated on demand and dual temperature zone temperature control that can be tailored to maintain an individual's optimum temperatures throughout the night.
Reference: Shahab Haghayegh et al. Before-bedtime passive body heating by warm shower or bath to improve sleep: A systematic review and meta-analysis, Sleep Medicine Reviews (2019). DOI: 10.1016/j.smrv.2019.04.008