After a night without enough sleep, the obvious solution is to sleep more. But real life does not always make that possible. Long shifts, travel, emergencies and demanding schedules can leave people trying to function while seriously sleep-deprived.

New research suggests there may be two temporary ways to protect memory in that situation: moderate-to-vigorous exercise or a nap. In a controlled study, people who either exercised for 20 minutes or slept for 90 minutes performed about 22% better on later memory tests than participants who did neither.

Thirty Hours Without Sleep

The study involved 54 healthy young adults who remained awake for 30 consecutive hours under laboratory supervision.

After the sleep-deprivation period, participants were randomly placed into one of three groups. One group completed 20 minutes of cycling at a moderate-to-vigorous intensity. Another group was given a 90-minute opportunity to sleep. The control group simply sat on a stationary bike for 20 minutes without exercising. Immediately afterward, participants viewed a series of images.

Three days later, researchers tested how well they remembered those images using a recognition task. Both the exercise and nap groups remembered significantly more than the control group.

A Short Workout Helped

The exercise intervention lasted only 20 minutes. That is important because the participants were already extremely tired after being awake for more than a full day. Despite that fatigue, a relatively brief cycling session appeared to help preserve their ability to form memories. Senior researcher Marc Roig explained that sleep deprivation affects many aspects of thinking and daily functioning, yet people cannot always immediately stop what they are doing and sleep. The findings suggest that a short bout of exercise may provide temporary cognitive support when proper rest is unavailable.

However, the researchers stressed that exercise should not be interpreted as a substitute for sleep.

Naps Worked Too

Participants who were allowed a 90-minute nap showed a similar improvement in memory. That result is perhaps less surprising, since sleep plays an essential role in restoring brain function. But brain recordings revealed that the nap and exercise did not appear to help in exactly the same way. Napping seemed to restore the brain’s ability to process and encode new information.

In simple terms, the brain appeared more refreshed and better prepared to take in what participants saw after waking. This may explain why the nap group later remembered more images.

Exercise Used a Different Pathway

Exercise produced a similar behavioral result, but the underlying brain activity looked different. Rather than simply “recharging” the brain, physical activity appeared to help participants use their remaining cognitive resources more efficiently. Importantly, the workout did not seem to make them feel even more exhausted. That makes exercise particularly interesting in situations where a nap is not realistic. A doctor in the middle of a shift, a transport worker, or an emergency responder may not be able to sleep for 90 minutes.

A short period of physical activity may be easier to fit into a break. The study suggests that exercise and sleep can arrive at similar memory outcomes through different neurological routes.

Why Memory Suffers

Sleep deprivation affects attention, decision-making, learning and memory.

When the brain is exhausted, it can become harder to properly encode new information. That means the problem is not only forgetting something later. The brain may fail to store the information effectively in the first place.This can be especially important in jobs where people must remember instructions, recognise details or make decisions after long hours awake. Even small cognitive declines can become significant when mistakes carry serious consequences.

Possible Workplace Uses

The researchers believe the findings could eventually contribute to fatigue-management strategies. Healthcare, transportation and emergency services are obvious examples. Employees in these sectors may sometimes work under conditions where sleep loss is difficult to avoid. First author Madhura Lotlikar noted that exercise is inexpensive, accessible and relatively easy to introduce.

That gives it a practical advantage over napping in some environments. Still, the study does not show that workers can safely compensate for chronic sleep deprivation simply by exercising. It examined a specific situation involving acute sleep loss and a small group of healthy young adults.

Important Limits

The participants were young and healthy, so the results may not apply equally to older adults or people with medical conditions. The study also involved one prolonged period of sleep deprivation rather than weeks or months of insufficient sleep. That distinction matters.

Chronic sleep loss has wide-ranging effects on physical and mental health that cannot be solved with a short workout. The research also focused specifically on memory performance, not every cognitive ability affected by fatigue. Other functions such as reaction time, judgment or emotional regulation may respond differently.

Nap or Exercise?

The findings do not establish one option as universally better. A nap appears to directly restore some of the brain function lost through sleep deprivation, while exercise may temporarily help the exhausted brain operate more efficiently/

Which option is practical will depend on the situation.