The worst exercise for your immunity, says science

If you know how to strengthen your immune system and strengthen your body’s defenses against infection and disease, you have probably read that exercise is a good idea. Numerous studies show that exercise is good for the immune system. This study, published in the Journal of Sport and Health Science, comes to the conclusion that moderate to intense exercise of less than 60 minutes puts the immune system into full swing and “the continuous exchange of different and highly active immune cell subtypes between the circulatory system and tissue.”

In addition, another research project published in the same scientific journal reports that aging, obesity and a sedentary lifestyle weaken the body’s defenses, reducing the overall risk of death from respiratory disease.

With the above in mind, the relationship between exercise and immune function seems clear: Exercise hard and your immune system will thank you! While for the most part this is true, there is one important caveat to be aware of. A particular sport seems to have the opposite effect, leading to a weakened immune system and greater susceptibility to infection. Read on to learn about the worst exercise for your immunity. And next, don’t miss the 3 Most Important Mysteries of Life Until 99, according to Betty White.


As with almost everything else in life, it is very important not to overdo it while exercising. It may be tempting to get yourself to hold out so much harder and longer, but moderation is an important aspect of fitness. Overtraining can actually backfire from an immunity standpoint, leading to a weakened immune system and a higher risk of developing a disease.

“Overtraining, which leads to chronic fatigue, decreased performance, and mood disorders, can impair immune function, leading to an increased likelihood of respiratory infections,” said David Nieman, Dr PH, FACSM, Professor of Health at Appalachian State University and Director of Human Performance Lab on the North Carolina Research Campus, said Runner’s World. It is important that Dr. Nieman is a lead author in the two aforementioned studies, so he is certainly qualified to comment on the complex relationship between exercise and immune function.

Another from Dr. A Nieman co-authored study published in the Journal of Sports Medicine and Physical Fitness found that runners were more likely to develop an infection after participating in a marathon. Why? Well, a marathon is as precise a definition as possible of intense, super-long training.

In addition, the first study mentioned above comes to the conclusion that “high training loads, competitive events and the associated physiological, metabolic and psychological stress are associated with transient immune disorders, inflammation, oxidative stress, muscle damage and an increased risk of illness.”

In summary, the training units should be kept under 90 minutes, with only short, high-intensity training units being used here and there. Another important factor is giving your body enough time to rest between workouts. “I recommend keeping exercise training at normal levels until this pandemic is under control,” said Dr. Neiman across from Runner’s World.

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In addition to exercise, regular enough sleep is another pillar of a strong immune function. In short, if you don’t get enough sleep, your immune system will weaken. Hence, it is important to consider the impact of exercise timing on sleep.

Recent research published in Sleep Medicine Reviews found that exercising nearly two hours before bed helps you fall asleep faster and sleep longer. From an immunity standpoint, that’s all well and good, but make sure you don’t break a sweat right before bed. The study authors add that exercising within two hours of hitting often results in rolling back and forth all night.

If you make the mistake of exercising right before bed, it can lead to both poor sleep and decreased immune function.

Related: Worst Time to Work Out, When You Like Sleep

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If you can, exercising outdoors during the day is a great way to get even more immune system benefits. Soaking in some rays of sunshine will increase your body’s natural production of vitamin D.

Vitamin D is an essential part of the regulation and function of the immune system. A number of diseases and conditions have been linked to vitamin D deficiency, and recent research even suggests that maintaining high levels of vitamin D may help protect against COVID-19.

Related: The Verdict on Taking Vitamin D Supplements for Your Immunity

Two women with protective face masks enjoy the outdoors during the coronavirusiStock

If all of these are making you fearful of breaking a sweat, don’t think too much about it. Exercise in general is a great habit for our immune systems, and our bodies in general, and only hampers immune function if we try too hard for too long.

Something as simple as taking a walk can go a long way in improving immune protection. A research published in Medicine & Science in Sports & Exercise reports that a 30-minute walk is enough to increase your white blood cell count.

For more information, see The Best Ways To Boost Your Immunity Naturally.