Many people associate exercise with better sleep at night. A new study has found that exercise performed at certain times today or just before going to bed alters how people sleep. One goal of the study was to determine how exercise and sleep are linked in more detail.
Researchers at Concordia University performed a meta-analysis recently published in a medical journal using data from 15 published studies. The goal was to determine how a single intensive exercise session affected both young and middle-aged healthy adults in the hours leading to bedtime. The correlation between exercise and sleep is difficult to determine because no two people are the same.
However, when reviewing the literature, the team found that a combination of factors interacted to modulate the effect of exercise on sleep. The team noted mixed results in the literature, with some suggesting benefits depended on the time of the exercise while others suggested the impact on sleep depended on the fitness level or type of exercise.
The principal goal of the meta-analysis was to determine if high-intensity exercise impacted sleep and determine what factors have the most impact. The statistical analysis examined multiple variables, including exercise timing in the hours between exercise and bedtime.
The analysis found that there were sleep benefits when a user exercised and ended the exercise two hours before bedtime. Among the benefits were faster sleep onset and increased sleep duration. However, researchers found if exercise ended less than two hours before bedtime, sleep was negatively impacted.
If exercise ended less than two hours before going to sleep, participants needed more time to fall asleep, and sleep duration decreased. High-intensity exercise in the early evening was the best for improved sleep onset and duration, particularly for sedentary subjects. The ideal duration for high-intensity exercise for sleep benefits was between 30 and 60 minutes. Cycling exercise, in particular, was found to benefit most for onset and deep sleep. Interestingly, exercise at high-intensity levels, no matter the timing, slightly decreased the REM stage of sleep.