Take a warm bath or shower in the evening

While it might sound contradictory to sit in a warm bath or take a warm shower to cool down the body, it does have a premise. When researchers did a meta-analysis of 17 studies on how water-based passive body heating, shower or bath, would impact various sleep metrics, they found a positive correlation. The data they investigated included sleep onset latency, awakenings after sleep onset, total sleep time, sleep efficiency, slow-wave sleep, and subjective sleep quality.