Over recent years, there has been great interest in the relationship between physical activity and mental acuity. It is becoming ever clearer that there is a positive link.
For instance, being physically active has been shown to fend off age-related cognitive decline.
However, the effects of a single, short burst of activity on cognitive performance are not as well-established.
Defining minimum effort
A review, published earlier this year, concluded that bouts of exercise lasting around 1 hour have significant benefits on executive function, which includes parameters such as attentional control, cognitive inhibition, inhibitory control, working memory, and cognitive flexibility.
Another study found that a 20-minute, one-off bout of exercise can benefit mental performance. But what is the smallest amount of exercise that can impart a measurable benefit to the brain?
Recently, researchers from Western University in Ontario, Canada, set out to understand whether there is a minimum amount of activity that can give significant benefits to one's brain. The study group was led by Prof. Matthew Heath, supervisor in the Graduate Program in Neuroscience.
He explains the importance of the study, saying, "Some people can't commit to a long-term exercise regime because of time or physical capacity."
Gaining an understanding of the minimum requirements could be very useful for these people. For someone who has trouble moving, knowing that even a small amount of exercise will be beneficial could offer valuable motivation.
10-minute bursts and the brain
For the current study, participants either sat and read a magazine for 10 minutes or carried out a 10-minute burst of moderate to vigorous activity on an exercise bike.
Following the activities, the participants' brain power was rated. Using sophisticated eye-tracking equipment, they measured their reaction times to a cognitively challenging eye-movement task called the antisaccade task.
For this task, people are asked to fixate on a stationary target, often a small dot. A second dot is then presented to one side of the stationary target. The individual is asked to move their eyes in the opposite direction from the stimulus. So, if a stimulus appears to the left of the initial target, participants must look to the right.
This task has been widely used to assess executive performance. The results of the new study were recently published in the journal Neuropsychologia.
"Those who had exercised showed immediate improvement. Their responses were more accurate and their reaction times were up to 50 milliseconds shorter than their pre-exercise values. That may seem minuscule, but it represented a 14 percent gain in cognitive performance in some instances."
Prof. Matthew Heath
What's happening in the brain?
The researchers believe that the burst of physical activity fires up the frontoparietal network, which is a part of the brain that has previously been implicated in exercise-based brain boosts.
For instance, a 2014 study revealed that an exercise program improved frontoparietal integrity in obese children. However, further studies will need to be done to accurately pinpoint the parts of the brain involved.
These findings could be important for a wide variety of people — for instance, anyone who has early stage dementia and is perhaps not able to move around for long periods of time.
As Prof. Heath says, "This shows that people can cycle or walk briskly for a short duration, even once, and find immediate benefits."
However, the findings are applicable for all of us. Prof. Heath gives further advice: "I always tell my students before they write a test or an exam or go into an interview — or do anything that is cognitively demanding — they should get some exercise first. Our study shows the brain's networks like it. They perform better."
The take-home message is that our brains thank us when we move about, even if it's just for a short time.