A study has found that 20 minutes of moderate treadmill exercise helped both young and older men react faster on tests of attention and self-control. mental health and physical activity. The results of this study suggest that even brief movements can temporarily sharpen mental processing without reducing accuracy.
Although exercise is often discussed in relation to long-term physical health, researchers have also found that even a single bout of exercise can affect the brain. One area of interest is inhibitory control, or the ability to ignore distractions and focus on what’s important. This ability is important in everyday life, from driving safely to resisting impulses and staying focused while working.
Inhibitory control is typically tested using the Stroop color word task. In this task, people see the word “red” printed in blue ink, and instead of reading the word, they have to say the color of the ink. This task causes mental conflict because reading words occurs automatically, while naming ink colors requires control. Older people often take longer to complete these types of tasks because their processing speed and attentional control can decrease with age.
The researchers wanted to find out not only whether exercise improves task performance, but also what happens in the brain during that improvement. A research team led by Kuo-Pin Wang of National Taiwan University studied 51 healthy adult men. The sample included 28 young adults with a mean age of 24.5 years and 23 older adults with a mean age of 70.1 years. The researchers recruited only men to avoid potential confounders related to sex-specific physiological and hormonal responses to acute exercise.
Each participant completed two separate sessions. In one, participants walked or ran on a treadmill for 20 minutes at a moderate intensity, defined as 60% to 70% of their heart rate reserve. The other one was sitting and watching the video. The order was counterbalanced, meaning that some participants did the exercise first and others completed the video condition first. After each session, participants performed the Stroop task and had their brain activity measured using electroencephalography, a non-invasive method that records electrical signals from the scalp.
The results showed that participants responded faster after exercising than after watching the video. Importantly, this fast performance does not come at the expense of accuracy. Simply put, the exercises seem to allow participants to work faster without making more mistakes. Both age groups benefited from exercise, although older adults were generally still slower than younger adults and had more difficulty on the most discrepant trials.
Brain recordings provided clues as to why this happened. The researchers found that after exercise, early brain responses associated with early visual processing and conflict monitoring were reduced. Subsequent brain patterns suggested increased attention and readiness to respond.
The authors described this as a “biphasic” effect. Exercise may reduce the mental effort required in the early stages and help the brain allocate resources more effectively later. This biphasic mechanism was observed across both young and elderly adult groups.
As the researchers write, “even a single intense exercise session can temporarily optimize neural efficiency.” In practical terms, this means that short periods of exercise may temporarily help the brain process information more efficiently, especially during tasks that require concentration and quick reactions.
The authors noted several limitations. Because this study tested only one exercise session, it cannot show whether repeated sessions result in lasting changes. This study included only men, so it is unclear whether the results generalize to women. Another caveat is that the researchers did not test participants before each session, so a quick response after exercise could reflect the true effects of exercise, a decline in performance after sitting and watching videos for an extended period of time, or both.
The study, “Move or look at a screen: 20 minutes of exercise modulates brain activity and improves cognitive performance in young and older men,” was authored by Kuo-Pin Wang, Li-Ju Chen, Chien-Lin Yu, Dong-Tai Chen, Tsung-Min Hung, and Shu-Shih Hsieh.
