Some days it can be downright difficult to muster the energy to exercise.
We’ve all been part of that shuffling race: the one where our feet do little more than walk.
It may seem futile in the moment, but new research suggests that even jogs that require minimal effort are ultimately worth it.
The study is the first to show that running, even at its slowest speed, is enough to induce a positive mood and promote executive function in the brain’s prefrontal cortex.
This region is important for both mood and cognition.
The results are published in Imaging Neurosciences.
Researchers from the University of Tsukuba in Japan conducted the experiment with 24 healthy young adults.
Each of these participants walked on the treadmill for 10 minutes and ran at a slow pace of about 3 to 6 kilometers per hour.
During each treadmill session, the average heart rate of male and female participants varied between 104 and 107 beats per minute.
Their progress was very modest – but it was a step in the right direction.
Compared to a day where participants spent 10 minutes sitting, after 10 minutes of running, they reported significant improvements in their mood, including greater alertness and feelings of enjoyment.
After a run, reaction times on a test of attention and self-control also improved compared to sitting.
During these cognitive tests, participants wore headsets that measured changes in levels of oxygenated hemoglobin on the surface of the brain.
Although this technique is not as precise as an MRI, it can indicate which areas of the brain are heavily activated during certain tasks.
After a race, these helmets recorded a stronger oxygen-rich blood signal in two areas of the left prefrontal cortex during cognitive tests.
A previous study by some of the same authors found that a 10-minute run of moderate intensity can also increase activation of the prefrontal cortex.
But this new experiment suggests that the cognitive and neural benefits of running are not necessarily limited to more demanding exercises.
The results are preliminary and do not compare walking to running, nor explore long-term associations.
But they suggest that very slow running positively affects both executive function and mood in the short term.
There are a few possible mechanisms that could explain these changes.
For example, it could be that running stimulates certain neural networks that project to the prefrontal cortex.
Or maybe it’s the head movement itself. In rodents, experiments suggest that when the head moves up and down rhythmically, it can mechanically stimulate the brain.
“This is a novel and challenging hypothesis, and the exact neural circuits involved in the positive effect of head acceleration on mood have not been identified and require further investigation,” the study authors explain.
That said, the researchers in the current study found that among their small group of young participants, head acceleration, influenced by very slow running, was positively correlated with exercise-induced enjoyment levels.
This factor explains about 17 percent of the variation in mood improvement scores between individuals.
Previous studies of low-intensity exercise and cognition have tended to focus on cycling because it is easier to control intensity.
But cycling may not get your head moving as much as jogging, and that could make a difference.
“This finding of the positive relationship between head acceleration and mood improvement may be one of the underlying mechanisms by which very slow running promotes mental health,” the authors hypothesize.
In fact, slow running might have been more important to our survival as a species than speed.
Humans evolved to run long distances standing on two legs. It’s one of our superpowers, allowing us to hunt large prey across the savannah.
“It is interesting to hypothesize that upright bipedal running in humans is also strongly linked to the evolutionary expansion of the Homo sapiens“frontal lobes and higher cognitive functions,” the researchers write.
“In this context, running can be viewed not just as another exercise modality, but as a biologically fundamental form of human movement that is particularly relevant to brain function.”
When the legs move, even at a slow pace, they also seem to move the brain.
The research was published in Imaging Neurosciences.
This article was fact-checked by Peter Dockrill and edited by Peter Dockrill. Although we are proud of our process, we are only human. If you spot an error, please let us know.
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