Biomedical engineers at The University of Texas at Austin have studied how people can get better sleep. Systematic review protocols allowed researchers to analyze thousands of studies linking water-based passive body heating, or bathing and showering with warm/hot water, with improved sleep quality. The scientists found that bathing 1-2 hours before bedtime in water of about 104-109 degrees Fahrenheit can significantly improve your sleep. The researchers found the optimal timing of bathing to improve sleep quality is about 90 minutes before going to bed. The research was published in the journal Sleep Medicine Reviews.