Does Running Weaken Immune System?

The benefits of running are well documented: it keeps your heart healthy, can de-stress the mind, improves stamina, and can help you keep the weight off.

However, what are the impacts on your immune system?

This is a topic that has been debated tirelessly by physiologists and scientists, but it seems running has both short and long-term impacts on your immune system. 

When we exercise, our heart rate increases due to adrenaline, and blood pumps through our body.

This causes our body’s white blood cells—your immune system cells—to race around as they attempt to fight off potential pathogens.

Physiologists at the University of Bath in the UK found that your immune cells double, triple, or even increase tenfold within seconds of you starting exercise.

Around 10 to 15 minutes after your workout, your cell count goes back to normal. But there’s also what’s known as an ‘open window’ in the immune system, whereby immune cells decrease to below normal levels, sometimes by half or more, and this can last for hours before finally returning to the normal level.

During this ‘open window,’ it’s thought that the immune system is suppressed, leaving people more susceptible to infection.

However, this isn’t necessarily the case, as what researchers have more recently found is that the immune cells haven’t disappeared during this window, they’re actually just out of the bloodstream and looking for infection. This process is known as ‘immune surveillance,’ and exercise, like running, can make this process more efficient.

Does Marathon Training weaken immune system?

Marathon training is tough, and overtraining can certainly trigger illness, burnout, or injury. However, marathon training won’t compromise your immune system, according to scientists.

What about elite athletes, though?

Those undergoing intense long-term training might be more susceptible to increased rates of upper respiratory infections (URIs), but this isn’t necessarily because of suppressed immune systems.

For example, those participating in marathons may sometimes complain of URI symptoms when they’re actually experiencing allergies or noninfectious issues which manifest in similar ways.

It’s not necessarily that marathon running itself weakens your immune system, but that marathon runners are more exposed to viruses. Think about it, there are thousands of runners in one space, droplets are exhaled and inhaled, surfaces are touched, water bottles shared, and so forth…

However, don’t let this put you off running a marathon. After all, this can be said of pretty much any social interaction, as the number one risk factor for coming down with an illness is exposure.

Do runners have better immune system?

Your immune system decreases with age, but it’s thought running could slow down this process. Long-term exercise and training can encourage a healthy, anti-inflammatory environment in the body, and specifically, running or regular exercise seems to strengthen the adaptive (or acquired) immune system.

The adaptive immune system is acquired over time, and your body creates antigens to fight specific infections. In 2018, a study found that 75-year-old cyclists had less immunosenescence (the immune system deterioration associated with aging) than 55-year-old people who did not exercise.

Researchers also found that the older subjects produced the same number of immune T cells (a type of white blood cell) as a 20-year-old.

This suggests that older adults who are fit and active might respond better to vaccines - something that has been backed up by a 2014 research paper, which found that short bouts of exercise and long-term exercise “significantly augments the immune response to vaccination.”

Can running cure diseases?

Exercise in general can help keep you in good health and reduce your risk of illness and chronic pain.

It’s not necessarily that running can cure diseases, but it can definitely help reduce your risk of acquiring them in the first place.

Regular exercise such as running has been linked to a reduced risk of many types of cancer according to a review of 170 epidemiological studies published in the Journal of Nutrition.

The most crucial lifestyle choices for reducing cancer recurrence rates were exercise and weight management, and research has also indicated that regular exercise can help relieve some of the side effects of cancer treatment, such as fatigue and nausea, for almost all cancer patients.

Cardiovascular exercise such as running is great for strengthening the heart and keeping blood pressure normal, according to the American Heart Association (AHA).

Just 150-minutes of brisk physical exercise per week is enough to keep blood pressure within the healthy range, and running has also been linked to other benefits, such as increasing good cholesterol (HDL) levels, lowering bad cholesterol (LDL), increasing your heart and lungs’ working capacity, and improving your blood flow, which can all help ward off heart disease.

Running has also been linked to healthier bones.

Osteoporosis affects 40 million people in the United States alone, according to the National Institute of Health. This condition is characterized by weak and easily broken bones, especially in the hips, spine, wrists, and shoulders, and is caused by a loss of bone density.

A study published in the European Journal of Applied Physiology examined the bone density of 122 marathon runners, as well as 81 half-marathon and 10K race athletes, and compared the athletes’ bones with those of 75 sedentary individuals.

As you might expect, the runners’ group had a much healthier bone density than the sedentary group, and the scans also showed that the half marathon and marathon runners had better bone density than the shorter distance athletes.

Running also helps you maintain a healthy weight, and this means you’re less likely to acquire the health issues associated with obesity - from diabetes to sleep apnea or heart disease.

Final Say

There’s no doubt that running is associated with a myriad of health benefits.

Not only can it strengthen your adaptive immune system in the long term, but it helps keep the weight off and can help you maintain a strong and healthy heart - which can further reduce your risk of acquiring the many diseases associated with a sedentary lifestyle and obesity.