Scientists Have Identified An Activity That Replaces Sleep

• 29.08.2026, 8:55

Just 20 minutes a day is enough.

Scientists have found that just 20 minutes of intense cycling improves memory in sleep-deprived people almost as much as a 90-minute nap—although these methods work in different ways. The study was published in the journal Proceedings of the National Academy of Sciences.

The experiment involved 54 healthy young adults who were deprived of sleep for 30 consecutive hours. During this time, some pedaled at a moderate-to-intense pace for 20 minutes, others rested, and a third group took a nap. Memory was tested three days after the intervention.

It turned out that exercise improved recognition of the memorized material by 21% compared to the control group, while a daytime nap improved it by 23%. In other words, in terms of effect, a short workout was almost as effective as a full night’s sleep.

But the pathways to this result differed. In those who slept, electroencephalography showed a reduction in signs of brain “fatigue,” whereas in those who exercised, these signals remained high. This means that exercise improves memory not by allowing the brain to rest, but through some other mechanism.

According to the authors, the advantage of physical activity lies in its accessibility: you can pedal or take a brisk walk even where it’s impossible to take a nap—for example, for shift workers or doctors. “Exercise is accessible, inexpensive, and easy to implement,” — noted the study’s lead author, Madhura Lotlikar. British scientists obtained similar results a year earlier: 20 minutes of moderate cycling improved mental performance in sleep-deprived individuals.

At the same time, the researchers emphasize that both sleep and exercise are only temporary aids, not substitutes for a full night’s rest, a lack of which affects 20 to 40% of adults worldwide and costs major economies approximately $680 billion a year due to decreased productivity.