While one in three American adults struggle with getting enough sleep, new research indicates that incorporating physical activity into a bedtime routine could help maintain cognitive sharpness, even when sleep is limited.
A study conducted at Concordia University in Montreal involved 88 healthy young adults to investigate the impact of physical activity on memory consolidation following sleep deprivation. Participants initially memorized 80 face-name pairs, performing equally well on an immediate recall test.
They were then divided into four groups. Two groups cycled on a stationary bike for 30 minutes, including warm-up and cool-down periods. One of these groups slept for 8.5 hours, while the other slept for only 4.5 hours. The remaining two groups, who also followed the same sleep schedules, rested quietly in a chair for 40 minutes instead of exercising before bed. The well-rested groups slept from 11 p.m. to 7:30 a.m., whereas the sleep-deprived groups slept from 2 a.m. to 7:30 a.m. Brain activity, eye movements, and heart activity were monitored during sleep.
Upon waking, participants were tested on their ability to recall the learned face-name pairs, alongside new ones. Significantly, the group that exercised for 30 minutes before their shortened sleep period performed comparably on the memory test to those who had a full 8.5 hours of sleep. This is particularly noteworthy as insufficient sleep can detrimentally affect the hippocampus, a brain region crucial for memory, learning, and decision-making.
The study highlights that sleep deprivation, especially when it reduces slow-wave sleep—the deepest stage of rest vital for processing and storing newly acquired information—can impair learning and retention capacity by up to 40%, according to the Sleep Foundation.
The findings suggest that a moderate evening workout may protect newly formed memories during consolidation, even with reduced sleep. Individuals who naturally experienced more slow-wave sleep appeared to benefit even more from the pre-bed exercise.
Beyond memory, physical activity before bed can also help regulate stress hormones like cortisol and release endorphins, potentially calming the mind and reducing anxious thoughts that can interfere with sleep. Exercise can also help synchronize the body's internal clock, promoting consistent sleep-wake patterns.
These findings emerge as insufficient sleep remains a widespread issue in the United States. Gallup polling indicates that over half of U.S. adults feel they would benefit from more sleep, with 20% reporting getting five hours or less per night in 2023, an increase from a decade prior. The recommended weekly physical activity for adults is 150 minutes of moderate-intensity aerobic exercise, a target that fewer than half of American adults currently meet.