If the list of benefits that exercise can bring was written in a book, it would be thousands of pages long. Think Lord of The Rings. Or War and Peace. Whatever genre you’re into.

We know about exercise and its effects on our physical fitness: stronger muscles, lower body fat percentages, better posture, more efficient energy usage, higher metabolism. Then you’ve got the links between mental health and exercise too. It improves mood, lowers stress levels, and gives you more headspace.

But it doesn’t end there. Exercise impacts our health and wellness in other ways too. One of the most underrated is the way it helps us fight illness and keep us well.


Does exercise improve immune function?


In short, the answer is yes. It, of course, depends on what exactly your immune system is being asked to fight and how much exercise you’re doing, but research is pretty consistent in showing that moderate-intensity exercise is linked to lower risk of illness.

This is particularly true for respiratory infections like the common cold and flu. It’s also shown to be more pronounced in those who exercise regularly.

Moderate-intensity exercise describes the type of workout that lasts less than an hour and isn’t too vigorous in nature. Think a spin class, a run, or circuits.

It’s important to point out that frequent vigorous and intense exercise actually starts to increase the risk of illness again if your body isn’t used to it. Overtraining is when the volume or intensity of exercise exceeds the body’s ability to recover from it properly. It’s at this point you’re more susceptible to illness.


How does exercise help the immune system?


The honest answer is that nobody quite knows for sure. There are four different theories behind how exercise helps fight illness and it’s likely that each one plays a part.

Exercise increases blood flow, meaning that antibodies and white blood cells that have a huge role in immune function circulate around your body more rapidly.

Exercise also increases your breathing rate in the short term and improves your respiratory function in the long term. This is said to help remove bacteria from your airways more efficiently.

The third theory is linked to the increase in body temperature that occurs when you exercise. Higher temperatures prevent bacteria from growing, meaning that breaking a sweat can stop an infection in its tracks.

The final theory is around exercise’s ability to reduce stress. High levels of stress are known to impair immune function, so anything that helps to reduce stress hormones is going to help avoid that.


What type of exercise is best for helping the immune system?


Most of the research into exercise and immune function looks at aerobic exercise. It’s this type of exercise that increases your blood flow, body temperature, and increases your breathing rate. The aim should be to reach 50-70% of your maximum heart rate to enter this aerobic zone. You can think of this as a scale of 1-10. If 1 is how you feel when watching TV on the sofa, and 10 is the maximum you could possibly give, a 5-7 is how you might feel when in the aerobic zone

There’s less research into how strength training can help your immune system, but we do know there are loads of other benefits to it. It definitely doesn’t stop your body fighting illness, so there’s still room and reason for it in your workouts.

The only type of exercise that doesn’t help your immune system is the type that’s too much. It’s quite hard to over train without realising, because your body is very good at telling you when it’s had enough. Your body needs to build up to high levels of fitness slowly and it doesn’t happen overnight. So, even if you’re on a mission to run a marathon, or become a powerlifter, take the time you need to recover between sessions before upping the intensity.