In this article published in Frontiers in Immunology, scientists reviewed decades of research on the relationship between physical activity and immune health. They found a strong correlation between the level of physical activity and the severity of symptoms of respiratory infections—the lower the levels of physical activity, the higher the chances of getting a respiratory illness and the worse the symptoms.

Sedentary lifestyles and low levels of physical activity are associated with increased levels of inflammation in the body, which scientists measure by looking at proinflammatory molecules (e.g., cytokines, interleukins, TNF, and C-reactive protein). These molecules are higher in the body when physical activity is chronically low. Researchers saw that increasing levels of physical activity—through both cardio and resistance training—improved immune health. But they caution not to perform strenuous exercise while you are symptomatic.

The key takeaway: Exercising (when you’re not sick) can decrease inflammation in the body and allow the immune system to work better.

After examining 48,440 adult patients with respiratory illnesses, researchers compared their symptoms to their activity levels: consistently inactive (0 to 10 minutes a week), some activity (11 to 149 minutes a week), and consistently meeting guidelines (150-plus minutes a week). The results showed that people who were consistently getting 150 minutes of physical activity or more a week had fewer symptoms and were less likely to be hospitalized due to the respiratory infection.

General health guidelines recommend regular moderate physical activity (30 to 60 minutes three to five days a week) to intense physical activity (30 to 45 minutes two to three times a week); meeting these guidelines is linked with decreased chances of developing an upper respiratory tract infection.

But after examining the significant decrease in daily physical activity that occurred during the height of the pandemic, some researchers suggest more exercise is needed to help lower symptoms related to respiratory illness (and improve mental well-being): 150 minutes of moderate exercise or 75 minutes of high-intensity physical activity three to five days a week. And in countries and areas where restrictions are still being imposed, 200 to 400 minutes of physical activity three to five times a week is needed to compensate for the continued lack of activity.

The key takeaway: How much exercise is needed for optimal immune heath varies depending on your lifestyle. Research shows that anywhere from 30 to 400 minutes three to five times a week is best.

Resistance training can help support the immune, cardiovascular, and respiratory systems. Multi-joint resistance training (i.e., using several muscle groups at once as opposed to isolating specific muscles) can improve muscle strength, muscle size, and body composition. And weights, resistance bands, or body weight can be used according to preference and convenience. Research shows that high-velocity resistance training (i.e., training with low to moderate weight and greater movement than traditional weight training) may be best for some people, especially older adults. Researchers recommend that resistance training be incorporated into recovery from respiratory illness and that it be personalized according to the patient’s needs and the severity of their illness and symptoms.

The key takeaway: Resistance training can support immune health. And using different muscle groups, low to moderate weight, and greater movement may be best for some people.