The COVID-19 pandemic has brought many changes to the lives of New Yorkers, including limited opportunities for exercise. While gyms, fitness studios, and yoga centers were shuttered, many New Yorkers turned to outdoor running in an attempt to boost their physical and mental health during this major public health crisis. Now that gyms are opening their doors again, novice runners are still sticking to their pandemic fitness routines—and with good reason!
A recent study published in The Journal of Neuroscience showed that voluntary physical activity in mice increases the brain’s resilience to psychological stress, which is a major risk factor for several mood disorders, including anxiety and depression. In fact, just three weeks of unrestricted access to a running wheel caused mice to display less anxiety-like behaviors in response to a light foot shock. This change was due to an increase in the levels of the protein called galanin. Galanin is produced in large quantities in the brain and spinal cord; its functional role in the central nervous system is widely debated, but several studies suggest that galanin might be important for coping with stress. To confirm that an exercise-related increase in galanin in the brain boosts stress resilience in mice, researchers used genetic tools to artificially increase galanin levels in the brains of sedentary mice. As a result, sedentary mice became just as resilient to stress as mice that had access to a running wheel but did not undergo any genetic manipulations. Would routine aerobic exercise confer a similar resistance to stress in humans? Considering how conserved the brain circuits that regulate stress responses are across species and how important they are for species survival, we would expect similar results in humans, though this has not been directly addressed. In addition, exactly how much aerobic exercise is necessary to give you nerves of steel remains unclear.
In the rodent experiment, mice ran up to 10-16 kilometers (6-9 miles) per day, which might not be feasible for us bipeds with full-time jobs. Moreover, high-volume and high-intensity running (such as often practiced by competitive runners) increases the risk of developing hip and/or knee osteoarthritis, a common condition that causes the protective tissue at the ends of bones known as cartilage to wear down. Conversely, recreational running protects your cartilage from wear and tear, especially when you compare recreational runners to people with a sedentary lifestyle. Taken together, these studies hint that there is a sweet spot when it comes to how much running you need to engage in to achieve maximal benefits for your physical and mental health. Although weekly running distance may vary depending on fitness level and exercise goals, studies suggest that clocking in as little as fifty minutes per week improves overall health and longevity and reduces mortality, especially when it comes to death from cardiovascular diseases and cancer. So, lace up, mask up, and get moving—your mind and your body could use a little more resilience.