The Centers for Disease Control (CDC) recommends that adults participate in 150 minutes of moderate-intensity physical activity per week, including two days of muscle-strengthening activity. This recommendation is based on thorough research related to the many benefits of exercise, including its effects on immune health. Engaging in regular exercise can significantly strengthen immune function, helping defend the body from infections, in the short- and long-term.
The Science Behind Exercise and Immunity
Exercise has a profound impact on the immune system. It increases a variety of hormones involved in metabolism, influences the body’s stress response, and activates the movement and function of several types of immune cells.1,2 Together, this results in improved immune health in cells but also body-wide, reducing the risk of infections in regular exercisers.2 While benefits begin after just one session, regular exercise can provide even more improvements to immune health by decreasing inflammation, decreasing stress, increasing the number of immune cells, and supporting the health of the thymus, the gland where important immune cells mature.2
It was previously believed that intense exercise could cause temporary issues within the immune system- increasing inflammation, putting heightened demands on the body’s metabolic systems, and causing a decrease in immune function.1 Scientists remain divided on this topic, but emerging data indicates that any transient suppression of the immune system does not result in increased susceptibility to infection.3 Other factors may explain why some intense endurance athletes have a high rate of infection, including crowded events, air travel, post-exercise inflammation, and changes to sleep routine.3
Types of Exercise and Their Impact on Immunity
In general, any type of physical activity will support immune health. Exercise provides benefits all the way down to cells, increasing circulation, decreasing inflammation, and optimizing important metabolic pathways, all of which enhance immune system function. But different forms of exercise may confer unique benefits. Aerobic exercise increases circulation, allowing immune cells to move throughout the body better where they can identify invaders and alert other immune cells.2 It also decreases inflammation, promoting an overall healthier environment for cells and organs.
Strength training, also known as weight training or resistance training, decreases inflammation, increases circulation and enhances immune cell function.4 Similar to aerobic exercise, the more consistent and routine strength training becomes, the greater the benefits.4 Finally, mindfulness-based exercises like yoga can greatly reduce stress and inflammation which support immune health as stress can suppress immune system function.5,6
There is strong scientific evidence demonstrating many beneficial effects that regular physical activity can exert on the immune system. However, finding the right amount and intensity of exercise is important to make sure exercise does not begin to negatively impact the body. Additionally, other lifestyle factors like diet and sleep, as well as non-modifiable factors including genetics, can impact the body’s response to exercise and overall immune system function. Engaging in regular exercise, getting enough sleep, and fueling the body with essential nutrients can synergistically support immune health.