Exercise four hours after learning improves long-term memory, study finds
A new study in the newspaper Current biology shows that physical exercise after learning improves memory and memory traces, but only if the exercise is performed in a specific time window and not immediately after learning.
“This shows that we can improve memory consolidation by playing sports after learning,” said the study’s corresponding author, Dr GuillÃ©n FernÃ¡ndez, from the University Medical Center in Radboud, the Netherlands.
In the study, Dr. FernÃ¡ndez and his co-authors tested the effects of a single exercise session after learning on memory consolidation and long-term memory.
âSeventy-two participants were randomly assigned to one of three groups matched by age and sex; all learned 90 image localization associations over a period of about 40 minutes, âthe scientists said.
âIn each group, half of the participants started at 9 am and half started at 12 noon to control the effects of the time of day. “
“After a basic cue booster test, participants in the Immediate Exercise (IE) group performed 35-minute interval training on an ergometer at an intensity of up to 80% of their maximum heart rate.”
âThe EI participants then moved to a separate, quiet environment for a three-hour period, where they watched nature documentaries, before returning to the exercise lab for a testing session. This control session did not involve exercise but used the same context otherwise.
âFor the deferred exercise (DE) group, the protocol was identical but with the order of the exercise session and reverse control; for the no exercise (NE) group, the two sessions before and after the delay period were control sessions.
Participants returned to the lab 48 hours after the initial encoding and performed a second recall test in the magnetic resonance (MR) scanner.
Scientists found that those who exercised four hours after their training session retained information better two days later than those who exercised immediately or not at all.
MRI images also showed that exercise after a delay was associated with more accurate representations in the hippocampus, an area important for learning and memory, when an individual answered a question correctly.
âOur results suggest that physical exercise at an appropriate time can improve long-term memory and highlight the potential of exercise as an intervention in educational and clinical settings,â the scientists said.
It is not yet clear exactly how or why delayed exercise has this effect on memory.
However, previous studies in laboratory animals suggest that natural chemicals in the body called catecholamines, including dopamine and norepinephrine, may improve memory consolidation.
One way to stimulate catecholamines is physical exercise.
“We will now use a similar experimental setup to further study the timing and molecular foundations of exercise and its influence on learning and memory,” said Dr FernÃ¡ndez.
Eelco V. van Dongen et al. Exercise performed four hours after learning improves memory retention and increases the similarity of the hippocampal pattern during recovery. Current biology, published online June 16, 2016; doi: 10.1016 / j.cub.2016.04.071