You likely know exercise can help keep every organ in your body healthy. But what about your immune system? As you might suspect, the answer is yes — with some caveats.

Numerous studies show that regular exercise may help prevent illnesses such as the common cold. One study from the British Journal of Sports Medicine reveals that men and women who exercised five or more days a week were 43 percent less likely to develop an upper respiratory tract infection. And research from the American Journal of Medicine found that postmenopausal women who walked for 45 minutes five times a week for a year had fewer colds than a control group who did stretching for the same amount of time. As study authors note, this dovetails with other data revealing that regular exercise can also help reduce the number of days you suffer from a cold. The main reason? Exercise, even just 30 minutes of brisk walking, increases the production of natural killer cells, white blood cells, and other immune system markers that help your body fight infection.

The benefits of exercise on the immune system don’t stop there, and an article from the American College of Sports Medicine (ACSM) highlights several other positive outcomes. “Having higher age and sex-adjusted scores for cardiorespiratory fitness and performing regular exercise of moderate- to vigorous-intensity exercise that fall within ACSM guidelines has been shown to improve immune responses to vaccination, lower chronic low-grade inflammation, and improve various immune markers in several disease states including cancer, HIV, cardiovascular disease, diabetes, cognitive impairment, and obesity,” writes Richard J. Simpson, Ph.D., an associate professor in the Departments of Nutritional Sciences, Pediatrics, and Immunobiology at the University of Arizona.

But what about COVID-19? Because this is a new virus, studies examining exercise’s role in either preventing or helping you recover from this specific virus don’t yet exist. But there is reason to believe that exercise could be a direct and indirect ally, especially given that exercise has benefits against other viral infections like the flu.

For starters, obesity and high blood pressure are the two most common comorbidities among folks hospitalized with COVID-19, according to new data from the Centers for Disease Control and Prevention. While exercise isn’t necessarily a weight loss strategy per se (most experts agree that exercise is more effective at weight management versus weight loss), it does have a positive effect on blood pressure. “Exercise can serve as a natural blood pressure control,” says Joel Kahn, MD, founder of the Kahn Center for Cardiac Longevity in Bingham Farms, Michigan, and author of Lipoprotein(a): The Heart’s Quiet Killer, adding that exercise can also help you maintain optimal blood sugar. That can be beneficial if you have diabetes, one of the conditions that may raise your risk of severe illness from COVID-19.

Exercise can also help counter the negative effects of stress, especially in this unique time of social distancing and home confinement. In a study published in the FASEB Journal, researchers studied how the isolation and confinement of space travel might impact immune function. “Those astronauts who had lower pre-flight fitness levels and returned to Earth with the greatest levels of cardiorespiratory deconditioning were more likely to have reactivated a virus during the mission,” Simpson, one of the study authors, writes. “Viral reactivation is a global indicator that our immune system has been weakened, which, in this context, we believe to be largely due to the stressors associated with isolation and confinement.”

Additionally, exercise can help improve sleep. When sleep deteriorates, your immune functioning can suffer, making you more prone to becoming sick. According to the National Sleep Foundation, when you don’t get enough or the right quality of sleep, your body can’t make as many cytokines, a protein that fights infection and inflammation. You’re then more susceptible to illnesses such as cold or flu.

Yet the dose of exercise matters, for while some exercise is good for your immune system, too much can be detrimental. “There may be excess inflammation with aggressive amounts of exercise,” Kahn says. High amounts of exercise, potentially anything over 60 minutes, and exercise that is high-intensity, can reduce immunity. In fact, research suggests that more than 90 minutes of high-intensity exercise can make athletes susceptible to illness for up to 72 hours after the workout.

Bottom line? Exercise can be a powerful tool for your mind and body during the COVID-19 pandemic, which could help support your immune system. Follow government guidelines and shoot for 150 to 300 minutes a week of moderate-intensity exercise (like brisk walking) or 75 to 150 minutes of vigorous-intensity aerobic exercise, or a combination of the two. And because studies show that getting out in nature is a mood lifter by itself, move those workouts outdoors. Just remember to practice physical distancing by staying at least six feet from others.