An analysis of decades of research into the cognitive effects of exercise suggests that even a single workout session can positively influence mental performance. The study, conducted by researchers at UC Santa Barbara and published in Communications Psychology, found that brief bouts of exercise have small but measurable impacts on cognitive tasks, particularly those requiring quick reactions and mental flexibility. However, these effects vary depending on the type, intensity, and timing of the exercise, as well as the cognitive task being performed.
While it is well-established that regular exercise enhances physical health and long-term brain function, the effects of single exercise sessions remain less clear. The researchers sought to address discrepancies in previous findings, which alternately suggested that single workouts improve, hinder, or have no effect on cognitive performance. They aimed to identify consistent patterns in the relationship between acute exercise and mental processes, with a particular focus on cognitive domains like attention, memory, and executive function.
“Human cognitive neuroscience is a field dedicated to understanding the neural mechanism of cognitive function and how they relate to behavior. The field is based on laboratory experiments in which participants engage in tasks that we can tightly control and measure performance. Sometimes we also do measurements of brain activity using a variety of neuroimaging methods,” said study author Barry Giesbrecht, a professor and head of the Attention Lab at UC Santa Barbara.
“In my lab, we are very interested in how exercise and other changes in physiological state influence these processes. One of the most consistent findings in the literature is that exercise interventions (e.g., something like a program that you would engage in ~3 times a week over months) improve cognition and can even promote neurogenesis. Studies looking at the effects of single, acute bouts of exercise are much more mixed, largely due to variability in the cognitive tasks and exercise protocol. Here, what we tried to do is get a sense of what the most consistent patterns were in the literature.”
To assess the cognitive effects of acute exercise, the researchers conducted a meta-analysis of studies published between 1995 and 2023. They included experimental studies that tested individuals aged 18 to 45, focusing on non-clinical, healthy participants. Eligible studies had to compare cognitive performance before and after exercise or between exercise and control conditions. Cognitive domains assessed ranged from executive function and attention to memory and motor skills.
The researchers conducted a meta-analysis, synthesizing data from 113 studies (with 4,390 participants in total) published between 1995 and 2023 to evaluate the effects of a single bout of exercise on cognitive performance. The studies included in the analysis were selected based on specific criteria: they had to involve experimental designs where participants performed cognitive tasks either during or after an acute exercise session. Eligible studies focused on healthy adults aged 18 to 45.
To ensure a broad perspective, the meta-analysis included various exercise types, such as cycling, running, high-intensity interval training (HIIT), resistance training, and sport-based activities. The intensity of exercise ranged from light to vigorous, and durations varied across studies. Cognitive tasks tested participants’ performance in domains such as memory, attention, executive function, motor skills, and decision-making. Reaction times and task accuracy were measured as primary indicators of cognitive performance.
The researchers employed Bayesian statistical methods to analyze the data. This approach allowed for a more nuanced understanding of the evidence, incorporating probabilities and variability between studies. Unlike traditional statistical methods, Bayesian analysis estimates the likelihood of certain outcomes given the observed data, making it particularly well-suited for assessing the heterogeneous effects of exercise on cognition. Moderators such as exercise type, intensity, duration, and timing relative to cognitive testing were included in the analysis to explore their influence on the results.
The meta-analysis revealed that a single bout of exercise had a small but significant positive effect on overall cognitive performance. Tasks targeting executive functions, such as inhibition and cognitive flexibility, were linked to the most consistent improvements. Attention and tasks requiring rapid reaction times also showed measurable enhancements. However, outcomes for memory and other cognitive domains were less consistent.
The researchers also identified significant moderators. For instance, the type of exercise played a critical role, with cycling and high-intensity interval training (HIIT) showing the most substantial cognitive benefits, particularly for executive functions such as inhibition and planning.
“With this particular finding, we have to be a bit careful because there are many fewer HIIT studies in the literature, so with more studies this may change,” Giesbrecht said.
The intensity of exercise also emerged as an important factor. Vigorous-intensity workouts produced the strongest cognitive enhancements, while moderate-intensity exercise yielded smaller but still noticeable benefits. These findings suggest that the physiological and neurochemical changes induced by higher-intensity exercise might underlie its superior impact on cognitive performance.
“We all know that consistent exercise has positive effects on emotional and cognitive function, in addition to the general improvements in health,” Giesbrecht told PsyPost. “Here we show that even a single acute bout of exercise can have positive effects on cognition, especially executive functioning.”
The researchers also observed substantial variability between studies, emphasizing the importance of context in interpreting the effects of exercise on cognition. Factors such as the design of cognitive tasks, participant demographics, and experimental protocols all contributed to differences in outcomes. For instance, simpler cognitive tasks may have reached ceiling effects, limiting the ability to detect exercise-induced improvements. Additionally, variations in how exercise intensity and duration were reported across studies introduced further complexity.
“While consistent, the overall effect of a single bout of exercise was generally on the small side,” Giesbrecht noted. “We think that an intriguing hypothesis that could explain this finding, besides the variability in the exercise protocols themselves, is that most studies have people engage in a cognitive task while exercising or shortly after exercise. This is very different than the real-world, which typically requires us to integrate the actions of our body and cognitive systems when doing daily activities. We are about to engage in a series of studies that will systematically test this idea using a combination of lab tasks and real-world activities.”
The paper, “A systematic review and Bayesian meta-analysis provide evidence for an effect of acute physical activity on cognition in young adults,” was authored by Jordan Garrett, Carly Chak, Tom Bullock, and Barry Giesbrecht.
