Having a relaxing soak before bedtime is the cornerstone of many people’s sleep routines, with the combination of warm water and some dedicated ‘me time’ helping to ease away the stresses of the day.
Now scientists have revealed the exact temperature our baths need to be at in order to signal to our bodies that bedtime is near.
In collaboration with the UT Health Science Center at Houston and the University of Southern California, UT researchers reviewed 5,322 studies linking water-based passive body heating, or bathing and showering with warm/hot water and improved sleep quality.
They found that the optimum bath temperature for improving overall sleep quality fell in the range of 104 and 109 degrees Fahrenheit (40-42 degrees Celsius).
And if a bath at this temperature is taken a 1-2 hours before we hit the hay, researchers also found that is can speed up the time it takes to fall asleep by 10 minutes on average.
Explaining the mechanics behind this bath-time formula, researchers wrote, ‘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.
‘Therefore, if baths are taken at the right biological time — 1-2 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.’
A past study by the University of Freiburg in Germany also looked at the impact of a 40C bath, but this time examining how it impacted people with depression.
The study group of 45 people with depression were either required to soak in 40C water for up to 30 minutes and afterwards wrap themselves in blankets and hot water bottles for additional 20 minutes, or take 40 – 45 minutes of aerobic exercise twice weekly.
Eight weeks later, those taking regular warm afternoon baths scored six points lower on a widely used depression scale, compared to three points lower on average for the aerobic exercise group.
Have you felt the beneficial impact of regular baths?