NEW YORK (Reuters Health) - Taking a hot bath one to two hours before bedtime can significantly improve sleep quality, according to a new study by scientists at the University of Texas at Austin.

Shehab Hagaieg, a professor of biomedical engineering at the university, said that human body temperature follows a rhythm that changes throughout the day. Usually, our bodies cool about an hour and a half before going to sleep.

One reason for this effect is that the pituitary gland regulates body temperature as well as a number of other functions, including the sleep-wake cycle, Hagage said.

Warm water can stimulate the body's thermal system, ensuring a natural cooling process, Hagagh said.

According to his team's findings, published in the journal Sleep Medicine Reviews, a temperature between 40 and 43 degrees can be ideal to increase the effect.

The analysis shows that water heating can improve total sleep time, intermittent slow sleep, sleep efficiency, or the amount of time we need to fall asleep. Data show that those who took the bath managed to sleep on average 10 minutes before. Researchers looked at previous data through a new lens

The researchers reviewed 5322 studies on sleep and temperature, then narrowed that down to 17 in particular, seeking data on the effect of water heating on a wide range of sleep measures, including late sleep time. The team used statistical methods to analyze the data.

Hagage emphasized that a warm bath should be in the range of one to two hours and taking it 15 minutes before bed was close to achieving the same effect.

Similarly, the temperature from 40 to 43 degrees was important. Just as hot water has the opposite effect of making our bodies cold before bed, cold showers make our bodies warm, making sleep more difficult.

In addition to helping us plan our evening work to help us get plenty of rest, this science can help engineers design technology that can improve sleep more.

The researchers at UT-Austin use the data as they work to build a water bed model that uses water to help regulate a person's body temperature, blood pressure and improve sleep overnight, Hagagh said.