A short bout of aerobic exercise or a 90‑minute nap can help protect memory after a night without sleep, a new study from McGill University found. Healthy young adults who either exercised for 20 minutes at moderate-to-vigorous intensity or took a 90‑minute nap after 30 hours awake performed noticeably better on a later memory test than those who stayed awake.
The study focused on episodic memory — the ability to remember events and experiences — which is particularly sensitive to sleep loss because sleep helps the brain encode new information. Researchers enrolled 54 healthy participants aged 18 to 35 who had no history of sleep disorders, did not work night shifts, and did not use sleep medications. After 30 hours of wakefulness, participants were assigned to one of three groups: a 20‑minute exercise session, a 90‑minute nap, or no intervention (control). They then viewed 150 color images to memorize. Three days after a recovery period, participants returned for a surprise recognition test that mixed the 150 old images with 75 new ones.
Performance was measured by the “hit rate,” the share of previously seen images correctly identified as old. The average hit rate was 0.46 for the control group, 0.56 for the exercise group, and 0.57 for the nap group. That translates to about a 21% improvement with exercise and a 23% improvement with the nap — roughly a 22% advantage for either intervention over no intervention.
EEG data suggested the two strategies improved memory through different mechanisms. Napping appeared to restore brain states more favorable to learning, while aerobic exercise seemed to enhance the brain’s ability to process and encode new information. In other words, both approaches helped protect memory formation after sleep deprivation, but they did so via distinct physiological pathways.
The authors and outside experts emphasize important caveats. The benefit observed was specific to the hit rate (protection of learning and memory formation) and did not imply broad improvements across all memory functions. The study population was limited to young, healthy adults who do not typically work nights, so it’s unclear whether the same results apply to older adults, people with chronic sleep disruption, or shift workers.
Experts also stress that neither naps nor exercise replace regular, healthy sleep. Consistently getting adequate sleep remains the best way to preserve cognition and overall health. Still, when sleep loss is unavoidable — for example, during exam periods, long shifts, or emergency situations — these findings suggest practical, nonpharmacological options to reduce short‑term memory impairment.
Practical considerations: a 90‑minute nap in the study produced strong benefits, but shorter naps (under 30 minutes) are often recommended in real life to avoid grogginess or disruption of nighttime sleep. Napping may not be feasible for many workers due to time, space, or job demands; in those cases, a brief session of aerobic exercise could be a useful alternative to support memory encoding.
Future research should test these interventions in real-world settings, in broader and older populations, and on job‑specific outcomes (for example, medical decision-making or error rates). For now, the take-home message is encouraging: the brain retains a notable capacity to adapt to short-term sleep loss, and simple measures like a short workout or a nap can help preserve the ability to learn and remember when adequate sleep isn’t possible.