一项研究发现，快走或慢跑能够刺激大脑神经细胞从而使神经官能放松达到镇静减压的作用。研究人员通过两组老鼠的对比实验发现，经常跑动的老鼠大脑中会产生大量能够抑制大脑活动并镇静兴奋细胞的神经元，在压力环境中，这些神经元能够迅速被大脑释放以抑制不必要的焦虑反应。研究人员指出，经常跑动的老鼠对抗压力的能力更强，这在人类身上也同样适用。
One of the best ways to relieve the stresses of the day is to simply walk them away, scientists have found.
Walking briskly or jogging really does calm you down by sparking nerve cells in the brain that relax the senses, new research has shown.
Exercise has long been thought to be effective for anxiety and depression, but the brain mechanism behind the phenomenon has remained a mystery.
Now tests on mice show when they are active, soothing neurons in the brain are triggered. When they are then exposed to a stressor, these neurons calm them down.
Researchers took two groups of animals, one that ran around and another that was sedentary, and then tested the amount of brain cells that formed after they exercised.
The runners' brains had a number of new neurons specifically designed to inhibit brain activity and quiet more excitable ones. The researchers then put the mice into ice cold baths to create a stressful environment.
As expected, large numbers of excitable neurons were fired up in the hippocampus, a region of the brain involved in emotional responses.
But in the brains of the runners, calming neurons were also quickly released warding off unnecessary anxiety.
The research shows exercising mice are able to cope better with stress, and it is believed the effect is also seen in humans, reports the Journal of Neuroscience.
Professor Elizabeth Gould, of Princeton University, New York, said physical activity reorganizes the brain so anxiety is less likely to interfere with normal function.
She said: 'Understanding how the brain regulates anxious behavior gives us potential clues about helping people with anxiety disorders.
'It also tells us something about how the brain modifies itself to respond optimally to its own environment.'
The findings resolve a paradox because exercise reduces anxiety while also promoting the growth of new neurons in the hippocampus.
Because these young cells are typically more excitable than their more mature counterparts, exercise should result in more anxiety, not less.
But the researchers found exercise also strengthens the mechanisms that prevent these brain cells from firing.
Prof Gould said identifying neurons and regions important to anxiety regulation may help scientists better understand and treat human anxiety disorders.
From an evolutionary standpoint, the research also shows the brain can be extremely adaptive and tailor its own processes to an organism's lifestyle or surroundings.
A higher likelihood of anxious behavior may have an adaptive advantage for less physically fit creatures.
Anxiety often manifests itself in avoidance behavior and avoiding potentially dangerous situations would increase the likelihood of survival, particularly for those less capable of responding with a 'fight or flight' reaction, added Prof Gould.