According to a recent study, an intense workout of 20 minutes can enhance long-term memory in healthy young adults, with respect to remembering previous events. While many studies have already shown that aerobic exercises such as running can improve memory, this study was different in that it had participants lift weights just once, two days before they were tested. Also, participants were asked to study events just before the exercise rather than afterward. This is because extensive animal research had suggested that the period after learning is when the arousal or stress caused by exercise is most likely to benefit memory.
The study began with every participant looking at a series of 90 photos on a computer screen. The images were evenly split between positive, negative and neutral. Initially the participants were not asked to remember the photos. Every participant then sat at a leg extension resistance exercise machine. Half of them extended and contracted each leg at their personal maximum effort for a total of 50 repetitions. The control group simply sat in the chair and allowed the machine and the experimenter to move their legs.
Throughout the process, each participant's blood pressure (BP) and heart rate were monitored. Every person also contributed saliva samples to test for levels of neurotransmitter markers linked to stress. Study participants returned to the lab 48 hours later and saw a series of 180 pictures, in which the 90 originals were mixed in with 90 new photos. Interestingly, the non-exercising control group was able to recall about 50 percent of the photos from the first session. However, subjects in the exercise group remembered about 60 percent.
This study indicates that people don't have to dedicate a lot of time to give their brain a boost. And although this particular study used weight-related exercises, resistance activities such as squats or knee bends will also likely produce the same results. While all participants remembered the positive and negative images better than the neutral ones, this pattern was more pronounced in the exercise participants who showed the greatest physiological responses. This result was expected since existing research on memory indicates that people are more likely to remember emotional experiences, especially after acute, short-term stress.
The research team plans to expand the scope of this study in the future. They want to try to determine its applicability to other types of memories as well as the optimal type and amount of resistance exercise needed for older adults and individuals with memory impairment. These findings are consistent with another study suggesting that aerobic fitness affects long-term memory. Of 75 young, healthy adult college students tested during a two-day period, those who were fitter retained information significantly better.
Overall, the findings from these two studies suggest that the increasingly sedentary lifestyles in the U.S. and other Western cultures may have adverse effects on long-term memory.