Memory can be a fickle thing, but a short burst of aerobic exercise may offer a simple way to give it a boost. New research suggests that a brief workout creates 'ripples' of electrical activity in the brain that help consolidate memories.
Scientists have long known that exercise benefits cognition, strengthening brain areas vulnerable to ageing and potentially slowing cognitive decline. Physical activity, in particular, can increase the size of the hippocampus, a region crucial for memory. The timing of exercise also matters: going for a walk four hours after learning can improve memory retention compared with exercising immediately afterwards.
Now, a study led by neuroscientist Michelle Voss at the University of Iowa has observed the brain's electrical activity directly after exercise. The team monitored 14 people with drug-resistant epilepsy, focusing on healthy parts of the brain. Participants exercised on a stationary bike while electrodes implanted in their brains recorded neural activity. The researchers found that after exercise, there was an increase in 'brain ripples' – bursts of activity where many neurons fire together – in the hippocampus and related areas.
These ripples, which are known to play a key role in packaging and storing memories during sleep and quiet rest, became more finely synchronised with activity elsewhere in the brain. 'These pulses were also more finely synchronised with neural activity in the rest of the brain,' Voss explained. Because ripples occur too quickly for standard brain scans to detect, this is the first study to show how exercise influences the brain's electrical activity directly.
The findings may explain why people often remember information better if they exercise shortly after learning it. Voss hopes the work will reframe public health messaging around physical activity and help protect the brain from cognitive decline in ageing. Even short bursts of exercise proved beneficial, and other research shows a single workout can improve focus for up to two hours and boost dopamine levels.
