It's already commonly thought that a warm bath before going to bed helps improve your sleep. A new meta-study has apparently confirmed this to be the case, however, and has even come up with exact figures regarding the best times and temperatures.
Taking warm bath at least 90 minutes before bedtime is your ticket to sound sleep. Just remember that the water temperature should be around 40-42 degrees Celsius, else you may not get better shuteye.
Working with colleagues at the University of Texas Health Science Center and the University of Southern California, researchers from the The University of Texas at Austin sifted through data from a total of 5,322 previous studies on the effects of pre-bedtime bathing on sleep quality.
The science behind these findings involves the body's circadian cycle, in which a person's core body temperature normally drops by about 0.5 to 1 ºF around an hour before their usual sleep time. Although it may seem counterintuitive, taking a warm bath reportedly helps facilitate such a drop, as it causes blood to circulate out from the core to extremities such as the hands and feet.
The researchers found 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.
The University of Texas team is now looking into the development of a commercially-viable bed system which would adjust users' body temperature throughout the night, keeping temperature changes in line with those that should be occurring naturally as part of the circadian cycle.
A paper on the research was recently published in the journal Sleep Medicine Review.