20 Minutes of Exercise Improves Long-Term Memory
While previous research has shown that several months of aerobic exercise can improve memory, a new study finds that doing exercise such as cycling, swimming, or running—even for as little as 20 minutes at a time—can boost one’s long-term memory skills.
Georgia Institute of Technology investigators, led by Georgia Tech graduate student Lisa Weinberg, recruited 46 participants—29 women and 17 men—who were randomly assigned into 2 groups. The first part of the experiment consisted of viewing a series of 90 images on a computer screen, which were split evenly between photographs that had been categorized as “positive,” “negative,” and “neutral.” According to the authors, the images included pictures of children playing on waterslides, photographs of clocks, and mutilated bodies, for example.
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Participants were then randomized into “active” and “passive” groups, and seated at leg-extension resistance exercise machines. The active group extended and contracted each leg 50 times, exerting maximum personal effort, according to the authors. Meanwhile, the passive group was instructed to sit in the machine’s chair and allow the machine to move their legs. The researchers monitored the blood pressure and heart rate of the participants, collecting their saliva samples as well.
Participants were shown the same 90 images 2 days later, although this time the photos were mixed with 90 new images that they had not seen before. According to the researchers, the active group recalled about 60% of the original images, while the passive group remembered about 50% of the initial photos. While all participants were better at recalling the positive and negative images than they were recollecting the neutral photos, this was even more true for the active group, the authors noted, suggesting this indicates people are more likely to remember emotional experiences following short-term stress.
Taken with past research, these findings “collectively lead to the suggestion that there is a possibility that some memory-related issues may be attenuated or prevented if the secretion of central norepinephrine is enhanced with resistance (or high-intensity) exercise in such populations,” says Shino Shinohara, PhD, FACSM, director of the Human Neuromuscular Physiology Lab and associate professor in the School of Applied Physiology at the Georgia Institute of Technology, and co-author of the study.
For primary care practitioners, “the most concrete advice we can offer is that even a short amount of resistance exercise can result in memory improvements,” adds Audrey Duarte, PhD, associate professor in the School of Psychology at the Georgia Institute of Technology, and study co-author.
“What we don’t know is how long these benefits last, and whether repeating this exercise a few times would result in even bigger memory benefits,” she says, “noting that “we are investigating this now.”
Timing of the exercise is important as well, continues Duarte.
“Exercising immediately after studying or reading will promote long-term memory for the learned material,” she concludes. “Exercising while trying to learn or remember will most likely not help and may even hurt memory. We are conducting those studies now.”
—Mark McGraw
Reference
Weinberg L, Hasni A, et al. A single bout of resistance exercise can enhance episodic memory performance. Acta Psychologica. 2014.