Fortunately, science is on our side. Experts tend to agree that, along with things like eating a healthy diet and getting enough sleep, regular exercise can boost immunity, as well as your mood. A 2014 study showed that endurance athletes with high training volume tend to have very few reported sick days. Another new study reported aerobic endurance exercise (such as running) improves the immune response better than resistance exercise, such as strength training.
In general, 45-minute sessions of moderate-intensity exercise is beneficial for boosting the immune system, according to John P. Higgins, M.D., a board-certified sports cardiologist at McGovern Medical School at the University of Texas Health Science Center at Houston and a certified personal trainer and exercise specialist. This is because it can increase immune cell levels and function, improve stress hormone levels and increase temperatures that may kill harmful bacteria and viruses.
However, it's also been suggested that hard workouts can have the opposite effect, which can explain why many runners feel weak and rundown in the days after running a marathon at a very hard effort.
"Overtraining, i.e. too much exercise and not enough recovery or increasing your exercise volume too fast too soon, is associated with reduced immune system functioning," Higgins says.
Thanks to the pandemic, the spring racing season has been virtually canceled, bringing the peak of marathon training to a halt. While it would be good to maintain moderate levels of activity, now would be the time to bring down your long runs and cut down on hard workouts to give yourself the best chance of staying healthy and avoiding any type of illness.
"My advice right now during the pandemic would be to include daily exercise (preferably aerobic) of 20 to 45 minutes per day total," Higgins says. "Mix it up with a fast walk/jog/run three to five days a week, bicycle/pushups/sit-ups/resistance exercises two days a week and yoga/stretching/balance exercises one day a week. You can replace each workout session with a high intensity 15- to 30-minute session if you wish, and if you do a long run (over 90 minutes in length), I would give yourself a full two-day rest break to recover."
With the current outbreak, health officials also maintain that anyone should avoid coming into contact with people they don't live with and to maintain a distance of 6 feet when you do. This includes running; if you attempt this, you'll see that it's fairly difficult to remain that far apart and hold a conversation, so it's really for the best to just run by yourself during this time. You should avoid your gym for this reason as well—and because it's one of the germiest environments you could find right now. So only opt for the treadmill if you have one at home. Lastly, stay home if you're feeling sick at all, even if you were going to run alone, to avoid exacerbating any potential illness or infection.