A Few Minutes of Exercise Today Could Do Wonders For Your Brain Tomorrow

Just a few minutes of exercise can have a powerful effect on your brain function, and those benefits to your memory and thinking skills might linger for longer than scientists thought.

Researchers at University College London and the University of Oxford have now found evidence that the acute cognitive benefits of physical activity persist not just for a few minutes or hours, as previous studies suggest, but to the following day.

The 'micro-longitudinal' experiment involved 76 British adults, who were cognitively healthy, between the ages of 50 and 83.

Each day for eight days, volunteers took a cognitive test that assessed attention, memory, executive function, processing speed, and psychomotor speed, which is the ability to detect and respond to quick environmental changes.

Throughout the study, activity levels and sleep were tracked using wearable devices as participants went about their normal lives.

Analyzing the data and accounting for contributing factors, researchers found that test scores for episodic and working memory were highest if, on the previous day, participants undertook relatively more moderate physical activity, like a brisk walk or anything that got the heart rate up.

Each additional 30 minutes of moderate activity on the previous day was associated with about a 0.15 standard deviation increase in score for episodic memory and working memory.

On the flip side, more sedentary behavior the day before had negative associations with working memory.

"These results were not substantively changed after taking into account sleep characteristics on the previous night," explain the authors, led by epidemiologist Mikaela Bloomberg from University College London.

Next, the team looked at sleep data on its own, independent of physical activity. They found that longer durations of sleep were tied to better episodic memory and psychomotor speed.

In particular, longer bouts of slow wave sleep were associated with better episodic memory, which includes memories of everyday events. Whereas more rapid eye movement sleep (REM) was linked to better attention scores the next day.

"This was a small study and so it needs to be replicated with a larger sample of participants before we can be certain about the results," admits Bloomberg.

At this point, considerable evidence exists to suggest that exercise is good for the brain in the short term, but whether or not those benefits last and for how long they last is less clear.

Co-author and epidemiologist Andrew Steptoe from UCL says the new study provides evidence that "the immediate cognitive benefits of exercise may last longer than we thought. It also suggests good sleep quality separately contributes to cognitive performance."

Exercise is generally agreed to increase blood flow to the brain, stimulating the release of neurotransmitters like endorphins.

One prominent hypothesis is that exercise increases the connectivity of neurons within the hippocampus, a part of the brain associated with memory and learning, and this is what gives memory function a boost following physical activity.

Recently, for instance, some studies have found that regular exercise can increase the volume of the hippocampus, which could possibly delay cognitive decline.

And earlier this year, a study from Australia found that high-intensity interval training (HIIT), maintained for half a year, could even help people retain cognitive sharpness for years on end.

Vigorous exercise can come with possible downsides to human health, and it's not possible for everyone so the fact that even moderate exercise can boost brain function is a positive sign.

It's getting difficult to ignore the fact that sedentary lifestyles are bad for physical health, and the same could be said of our brain function, too.

The study was published in the International Journal of Behavioral Nutrition and Physical Activity.