For better recall, try a work out four hours after learning something

Working up a sweat may release molecules that help with memory banking.

Beth Mole – Jun 19, 2016 5:50 pm | 31

To make sure you’ll be able to jog your memory quickly, you might want to go for an actual jog a little after learning something.

Healthy volunteers that exercised four hours after learning patterns had better recall 48 hours later than those that didn’t exercise at all or exercised directly after learning. The delayed exercise may spur the release of molecules that boost the brain’s normal ability to consolidate and bank memories for long-term storage, researchers report in the journal Current Biology. If the finding holds up in further studies, it may suggest that working out a little after cramming could help bulk up your noggin.

For the study, researchers had 72 healthy volunteers spend 40 minutes learning the location of 90 objects on a screen—like a cartoon beach ball on the center right. The researchers immediately tested how well each participant did learning the objects’ locations, then split up the participants into three groups. One group went directly into a 35-minute interval training on a stationary bike (with an intensity of up to 80 percent of their maximum heart rate). The second group went into a quiet room and watched nature documentaries until it was time for their four-hour delayed workout. And a third group acted as the control group, which just watched nature documentaries and hung out—but didn’t work out—in the gym.

To make sure that the time of day didn’t interfere with the participants’ memory results, the researchers also subdivided each group so that some volunteers started the whole experiment at 9am and others started at noon.

The researchers re-tested all of the participants’ memories two days later. They found that the control group and the immediate exercise group did about the same on the memory test. Those in the delayed exercise group, however, had better scores overall. The researchers made sure to account for individual participants’ scores on the first memory test so that people with just really good or really shoddy memories didn’t throw off the results.

To back up the finding, the researchers next looked at functional magnetic resonance images of the participants’ brains—which show brain activity based on blood flow. The images revealed that when participants in the delayed exercise group were re-taking the memory test, they had stronger activity patterns in their brains’ hippocampus—a part involved in memory—compared with the other groups.

Though the study doesn’t explain why delayed exercise boosts memory, the authors speculate that it could be triggered by exercise-induced molecules in the blood. Working up a sweat is known to release molecules that alter the brain, such as dopamine, noradrenaline, and a protein called BDNF that promotes the growth and development of brain cells. Such molecules, the authors say, are critical for solidifying and storing memories for long-term retrieval. Thus, a flood of these molecules might not have a useful effect when memories are fresh, but may make a big difference a little later when the brain is packing memories away for safe storage.

Scientists will have to do more research to confirm that hunch. Also, the authors point out, while a four-hour delay boosted memory in this study, the experiment didn’t test different delay times—two hours, six hours, etc.—to see which one might be optimal for bulking up memory. The researchers are also unsure if the brawny recall will hold up over time periods longer than a couple of days.

Still, in the meantime, if you’re cramming for an upcoming test or big presentation, a delayed workout might just help train your brain.

Current Biology, 2016. DOI: 10.1016/j.cub.2016.04.071 (About DOIs).