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So does regular exercise actually help your immune system protect you against disease and infection?
Well, there’s not a whole lot of argument that exercise and other physical activity is an important part of a healthy life. The healthiest people in the world move regularly. Whether it’s the famous centenarians from the world’s Blue Zones or high performers in sports and business (or even playing with grandkids), the people who stay the healthiest don’t just sit there. They move—daily.
The question you might have is “Can I use exercise to protect myself from infectious illness?” It’s a little more obvious to see how it can improve fitness and help with things like cardiovascular function. But what does exercise have to do with immunity?
Believe it or not, there is evidence that exercise is not only helpful in the defense against things like cancer and heart disease, but also viral and bacterial infections.
And there are a lot of good reasons why. From improved tolerance to stress to the physical changes that take place when you exercise, exercise has a pretty nice set of mechanisms that can help fight off infections.
One of the best side effects (I know I get) from exercise is stress relief—and stress definitely weakens your immune system. Maybe one of the reasons is that exercise slows down the release of stress hormones and stress hormones can suppress your immune system’s effectiveness. Even if I don’t want to exercise—if I’m feeling stressed or depressed—but I do it anyway, I always feel better. Maybe it’s just because I give myself a chance to stop thinking about what’s bothering me. Whatever it is, that relief from stress improves my ability to fight infection.
Another important benefit of exercise is improved circulation, which allows the parts of the immune system, like immune cells and antibodies, to move more freely through your body and be more efficient at their job. It’s like improved mass transit for your entire immune workforce. This means they’re not just better and faster at fighting against foreign invaders but also at helping to properly moderate your inflammation response, another important part of a strong immune system.
Flushing out bacteria
Physical activity that gets your blood pumping can also help flush bacteria out of your lungs and airways (kind of like a whole body sneeze), which can reduce the risk of those taking hold and you getting the cold or flu.
And to peek into some territory I’ll talk about in another post, regular exercise is an important player in a good night’s sleep. And good sleep is important for a healthy immune system. I’ll talk about it more next time, but exercise helps you fall asleep more easily, reduces insomnia (maybe it’s that decrease in stress and anxiety), and increases the amount of deep sleep you get. Just be careful—some people find it hard to fall asleep if they work out too late in the evening. Give yourself a couple of hours to wind down after exercise before you have to go to bed.
One thing to be aware of, though. Too much exercise or an exercise routine that is too intense can increase stress and decrease immunity. That doesn’t mean you can’t work out hard. It’s not about getting regular intensity in your workout—you need some intensity if you want to get fit. If you’re getting 30-40 minutes of exercise a day, even with regular bouts of high-intensity thrown in, you’re probably doing fine. If you already exercise, though, you don’t need to increase just to boost your immunity. Just keep in mind that long-term intense training (like what you might do if you were training for a marathon) without recovery can actually cause physical stress and harm to your immune system.
Get your daily exercise in! It’s good for fitness and it’s a good idea if you’re at all worried about getting sick.
A good framework is:
- 20–30 minutes of aerobic activity 3-4 days a week. As a rule of thumb, this kind of intensity is something like “it’s getting annoying to talk”—not gasping for air.
- Along with 1–2 shorter high intensity workouts a week. Intensity here is something like “late for your flight, escalator broken, carrying a suitcases and a kid” (thanks to Peter Attia, MD for the best vivid description of this intensity I’ve ever heard).