NEW DELHI: Forgotten where you put your keys, struggled to recall something you just read or found it harder to absorb new information after a sleepless night? There may be reason for that. Sleep deprivation can make it harder for the brain to form new memories. But a brief bout of exercise may help counter some of that damage, a new study suggests.Researchers found that 20 minutes of aerobic exercise helped preserve the ability to form new memories even after 30 hours without sleep. A 90-minute nap offered a comparable benefit, with both groups performing around 22% better on a memory task than participants who received no intervention.Published in the Proceedings of the National Academy of Sciences, the study involved 53 healthy adults aged 18 to 35 who were kept awake for 30 hours under laboratory monitoring. They were divided into three groups – 18 did 20 minutes of aerobic exercise, 18 took a 90-minute nap and 17 sat on an exercise bike for 20 minutes without exercising as the control group. When tested on image recognition three days later, the exercise group correctly recognised 56% of the images, the nap group 57% and the control group 46%. Difference between the exercise and nap groups was not statistically significant.Electroencephalography (EEG) recordings suggested that the two interventions supported memory through different neural mechanisms. In the nap group, changes linked to reduced sleep pressure and neural fatigue helped explain performance, while in the exercise group, how the brain processed incoming information was more closely linked to successful memory formation. The findings may be relevant to people in sleep-deprived professions, including healthcare, though the study did not establish benefits in real-world settings.Prof Manjari Tripathi, head of neurology at AIIMS, said deep non-REM sleep helps consolidate episodic memories, while REM (rapid eye movement) sleep supports emotional memory processing. Repeated sleep deprivation can cause brain fog, fatigue, poor memory and emotional outbursts, and may raise depression risk. Short naps of around 15 minutes may help night-shift workers, but cannot replace seven-eight hours of consolidated sleep.Dr JC Suri, director and head of pulmonary, critical care and sleep medicine at Sitaram Bhartia Institute of Science and Research, said the findings showed a “genuine but narrow protective effect” on episodic memory after acute sleep deprivation.Since the study involved acute sleep deprivation in healthy young adults, further research is needed to establish whether the benefits extend to chronic sleep insufficiency or real-world settings.
