Harvard Men's Health Watch

Need to remember something? Exercise four hours later

In the Journals

Here's a possible strategy to boost memory—exercise four hours after you learn something. In a study published in the July 11, 2016, Current Biology, researchers found that exercise after learning may improve your memory of the new information, but only if done in a specific time window.

In the study, 72 subjects learned 90 picture-location associations—mentally linking an image with new information in order to improve recall—over a 40-minute period. They were then randomly assigned to one of three groups: one group exercised immediately, the second exercised four hours later, and the third did not exercise. The exercise routine consisted of 35 minutes of interval training on a fitness bike at an intensity of up to 80% of maximum heart rate.

After 48 hours, the participants' memory was tested while their brains were scanned via MRI. Those who exercised four hours after the learning session retained information better than the other two groups. The MRI also showed that the hippocampus, the brain region involved with learning and memory, was more active when information was recalled correctly.

Newly learned information turns into long-term knowledge through a process that requires certain brain chemicals that are released during exercise, such as dopamine, noradrenaline, and the growth factor BDNF, according to the researchers, but more research is needed to understand this phenomenon. It is also not clear why four hours was more beneficial, or if another time frame might produce a similar effect.