Many people ask me “Does a warm bath help sleep, or is that just a myth?” The research shows . . .
Yes, it seems to help somewhat. Medical research has investigated the impact of both baths and foot baths on sleep. One study in older people with sleep disturbance found that a 40 minute footbath at 41C decreased wakefulness in the second nonREM sleep period. Women undergoing chemotherapy for cancer have also found increased sleep quality with a warm footbath. Another study done in elderly insomniacs found that a full-body bath (immersed to the mid-chest) for 30 minutes at 40-41C did increase deep sleep, and caused people to experience a good night sleep. .
How does a warm bath improve sleep? Human body temperature is not constant, but varies with a consistent circadian rhythm. There is a slight dip in body temperature at approximately 1pm, and then a more significant drop in the evening hours. We get that sleepy feeling as our body temperature drops. The bath effectively raises our body temperature, and the subsequent drop helps sleep. The bath should be about 60-90 minutes before bedtime.
Of all the means you can use to improve your sleep, this one seems one of the most simple, with the least possible negative side effects. This is a good therapy to try first before using other, more invasive medicine.