Does Exercise Improve Your Immune System? Here's What the Research Says

Have you ever crossed the finish line of a race beaming with joy and a sense of accomplishment, just to get hit with the sniffles a few days later? You’re not alone. A 2019 review in the Journal of Sports and Health Science found that athletes who engage in intensive prolonged training and/or competitions have an increased risk of catching an illness. However, the good news is not all types of exercise harm your immune system. In fact, engaging in moderate exercise may actually help improve your immune system and help you stay healthy.

In this article, we will explore the link between exercise and the immune system, discuss how the type and duration of exercise can affect immune function, and explain how much exercise you really need to help improve your immune system.

What’s the Link Between Our Immune System and Exercise?

You can think of the immune system as your body’s invisible protective armor. Although we can’t see it, it works hard to keep us healthy and rid our bodies of any foreign or harmful substances. The immune system recognizes outside invaders carrying disease-causing germs, viruses or bacteria, and works to battle them and remove them from our bodies, according to the National Library of Medicine.

There are also many things we can do to support a strong and well-running immune system, such as eating nutritious foods, getting sufficient sleep, managing our stress levels and exercising regularly.  However, the type of exercise you do, the intensity at which you exercise and the duration of your exercise all matter and can impact your immune system.

How Much Exercise Should I Do to Improve My Immune System?

The Physical Activity Guidelines for Americans state that adults should do at least 150 minutes of moderate-to-intense aerobic activity per week, along with two days a week of strength training that works all major muscle groups. You can meet this goal by going for a 30-minute brisk walk, jog or swim five days a week. If you break into a sweat and your heart rate has gone up, that’s a good indicator you’ve hit a moderate aerobic pace. 

Lifting free weights, using weight machines at the gym or attending an exercise class all could count toward meeting your strength-training goal. There’s no set amount of time you need to do this for, but you should aim to work all major muscle groups two times per week.

Being active is associated with a plethora of health benefits, including stronger bones and muscles, brain health, healthy weight management and reduced risk of disease and infections, according to the Centers for Disease Control and Prevention.

How Does Exercise Positively Affect the Immune System?

Research states that the immune system is very responsive to exercise, and how much a person does and at what intensity may either positively or negatively impact the immune system. Engaging in moderate-to-intense aerobic activity for less than 60 minutes daily is said to help enhance immune function. More immune cells are released in the bloodstream to help fight off infections and harmful pathogens, stress hormones like cortisol are lowered, and levels of bodily inflammation are also reduced.

Regular physical activity may also lower the risk of COVID-19 infection, hospitalization and severe illness, compared to adults who were not active, according to a meta-analysis published in August 2022 in the British Journal of Sports Medicine.

Lifting weights can also help increase the number and improve the functioning of immune cells. According to a 2022 systematic review of 13 studies published in Experimental Gerontology, even one session of resistance training enhanced immune functioning in both young and older adults. Researchers also found that participants who engaged in regular resistance training for several weeks saw the most benefits.

Although some people might want to really amp up their immune system prior to a period of intense training such as pre-season training camp or a marathon, engaging in more exercise doesn’t help your immune system. In fact, engaging in long, intense workouts may actually compromise your immune system’s ability to do its job.

How Might Exercise Negatively Affect the Immune System?

Athletes who engage in prolonged, intensive exercise may be more susceptible to a weakened immune system. This includes any athlete who does intensive endurance-based activity for 90 minutes or more, such as training for or competing in a marathon, triathlon or long-distance cycling event. A 2021 review published in Clinical and Experimental Medicine found that these activities were linked to immune dysfunction and oxidative stress.

A systematic review of 18 studies published in January 2020 in Frontiers in Physiology found that excessive prolonged activity caused a greater inflammatory response than moderate activity. A 2021 study published in PLOS found that elite athletes had a 7-fold increased risk of developing a respiratory tract infection during competition.

Others argue that prolonged, intense exercise should not be solely blamed, as other factors around competition, such as being surrounded by large crowds, traveling, sleep disruptions, poor diet and added mental stress, may also wreak havoc on the immune system.

The Bottom Line

Engaging in regular, moderate-to-intense aerobic exercise and strength training may help improve the function of the immune system, while overdoing it may weaken it. Additionally, eating a nutritious diet, getting adequate sleep and managing stress levels can also help support a strong and healthy immune system.