Running can help stave off the negative effects of stress and protect the brain region responsible for learning and memory, a study has found.
"Exercise is a simple and cost-effective way to eliminate the negative impacts on memory of chronic stress," said Jeff Edwards, associate professor at Brigham Young University in the US.
Inside the hippocampus, memory formation and recall occur optimally when the synapses or connections between neurons are strengthened over time.
That process of synaptic strengthening is called long-term potentiation (LTP). Chronic or prolonged stress weakens the synapses, which decreases LTP and ultimately impacts memory.
The study, published in the journal of Neurobiology of Learning and Memory, found that when exercise co-occurs with stress, LTP levels are not decreased, but remain normal.
Researchers carried out experiments with mice. One group of mice used running wheels over a 4-week period (averaging five kilometre an per day) while another set of mice was left sedentary.
Half of each group was then exposed to stress-inducing situations, such as walking on an elevated platform or swimming in cold water.
One hour after stress induction researchers carried out electrophysiology experiments on the animals' brains to measure the LTP.
Stressed mice who had exercised had significantly greater LTP than the stressed mice who did not run.
Researchers also found that stressed mice who exercised performed just as well as non-stressed mice who exercised on a maze-running experiment testing their memory.
They also found that exercising mice made significantly fewer memory errors in the maze than the sedentary mice.
The findings reveal exercise is a viable method to protect learning and memory mechanisms from the negative cognitive impacts of chronic stress on the brain.
"The ideal situation for improving learning and memory would be to experience no stress and to exercise. Of course, we can't always control stress in our lives, but we can control how much we exercise," Edwards said.
"It's empowering to know that we can combat the negative impacts of stress on our brains just by getting out and running," he said.
