• Exercise boosts immunity: With each bout of exercise, studies show that you’ll improve the antipathogen (disease-fighting) activity in your tissues, you’ll reduce inflammation, and enhance your overall immunity.
Protection while you rest: Studies show that after exercise, the cells inside our muscle produce increased amounts of immunity-protecting molecules.
• Sitting equals sickness: The most sedentary people have the highest risk of getting sick with colds and flu and are also at a much higher risk of suffering from many chronic diseases. Multiple studies show that when adults regularly workout, they cut their chances of getting sick.
• When exercise hurts immunity: The general rule is that if you have symptoms that are primarily above the neck—stuffed or runny nose, sneezing, sore throat—exercise is okay. However, if you have body-wide symptoms, then rest is best.
• Exercise after an illness: Make sure that you no longer have a fever. Easy does it, listen to your body, and start back gradually.
As with many things having to do with your health, “balance” is the word when it comes to using physical activity to boost your immunity. In many respects, actively moving is both good for what ails you, or what would like to ail you—big and small. Studies show that those who exercise regularly are at a lower risk of heart disease, diabetes, obesity, cancer, improved mental health, sleep, stronger bones and muscles, and a longer life than those who live sedentary lives. When it comes to other infections and viruses such as colds and flu of all sorts, physical activity also seems to help your body’s disease-fighting system and recovery process.
Your body is constantly being bombarded by pathogens. Comprised of a complex network of cells, organs, and chemicals, your immune system (if healthy) can recognize and destroy threats that would otherwise make you sick. This is a never-ending job for our immune systems. You can help or hurt your body’s disease-fighting, health-protecting system by your choices and habits with diet, sleep, daily stressors, and emotions. When it comes to physical activity, the correct amount of exercise enhances your body’s ability to fight infections and to heal you after injury or illness. And while you probably know that too little activity isn’t good, you may not know that neither is too much. Knowing the difference is essential.
Pushing yourself to keep up with an intense regimen of fitness while you are fighting the flu, strep throat, or bronchitis, for example—probably won’t help, and it could hurt. When your immune system is busy fighting bacterial or viral infections, rest might be best. It’s important to listen to your body. If you feel up to it, a gentle walk might be okay, but if you have a fever, body aches, a flaming throat, or trouble breathing, then exercising could put you out of commission for longer than staying in bed. Let’s examine how exercise works to protect and enhance your immune response:
Protect with Regular and Frequent Exercise: Obesity, diabetes, heart disease, arthritis, cancer, Alzheimer’s—you name it, and chances are that fitness lowers your risk compared to being sedentary. Overall, being active reduces the risk of all chronic disease and lessens your chances of getting sick or being injured. Regular exercise also helps to enhance your immune system in many indirect pathways. Improvements in muscle strength, bone health, motor coordination, gut function, sleep, and mood all help to support and build a healthy immunity. With each bout of exercise, studies show that you’ll improve the antipathogen (disease-fighting) activity in your tissues, you’ll reduce inflammation, and enhance overall immunity. Aim to get 30 to 45 minutes of moderate-intensity exercise most days of the week. Add to that two bouts of strength training and some flexibility sessions, and you’ll be good to go.
The After-Exercise Immunity Benefits: Studies show that after exercise, the cells inside our muscles produce several molecules that protect immune responses in the body. One of them is interleukin-15 (IL-15), which improves bone health and sleep, and also helps your immune cells respond to microbial invaders and parasites. Another benefit to those who exercise is the increased production of irisin, a molecule linked to reduced obesity and sleep apnea, both markers of weakened immunity. Finally, regular exercise increases the level of the enzyme heme, an essential iron-containing molecule that carries oxygen to all our tissues. Heme activates immune cells to destroy disease in the body.
The More You Sit—The Sicker You’ll Get: It’s true. The most sedentary people are at the highest risk of getting sick with colds and flu and have a higher risk of heart disease, cancer, diabetes, high blood pressure, arthritis, even Alzheimer’s, and more. The good news? You can reap benefits by starting with as little as 10 to 15 minutes of easy walking. Even light activities such as gardening, walking, and housework lower inflammatory markers in the body that are associated with illness and disease.
Exercising Lowers Colds and Flu Risk: The trick with exercise is to do it before you get sick. Multiple studies show that when adults regularly workout, they cut their chances of getting sick. Plus, when exercisers do get sick, the illness tends to be milder and recovery faster than non-exercisers. There is evidence that regular activity strengthens the antibodies that fight colds and flu. Even if you aren’t currently following a regular exercise routine, getting active right now (as long as you aren’t already sick) can lower your chances of illness, chronic disease, and will strengthen your immunity.
The Rare Case of Too Much Exercise: An overuse injury can happen by taking on too much or too intense of an exercise too quickly, or by not taking a rest when your body tells you it needs one. Your muscles, ligaments, and tendons can all get strained or torn in these cases. While your body often sends signals in the form of pain, you’ve got to be “listening” carefully to pick up the difference between a pain that indicates normal muscle soreness from a good workout, and pain that signifies overuse. Know the symptoms of too much exercise. Harmless achiness after a workout usually presents as stiffness, soreness, fatigue, or even burning. More severe injuries tend to present as pain that is stabbing, sharp, or deep in an area that doesn’t usually hurt. Symptoms of overuse don’t always mean that you need to stop all activity but do take care and possibly switch to a less intense form of exercise for a few days.
How do I know when I am too sick to exercise? With a mild illness such as a cold, you may benefit from moderate to easy exercise. There is some evidence that it may help to flush bacteria out of the lungs and airways. The general rule is that if you have symptoms that are primarily above the neck—stuffed or runny nose, sneezing, sore throat—exercise is okay. However, if you have body-wide symptoms such as fever, aches, chest congestion, stomach distress, diarrhea—then it is best to rest. Some studies show that the immune system is depressed during intense physical exertion, so no marathon training with a fever. If you still insist on exercising, modify your intensity or duration. Walk for 15 to 30 minutes instead of running for an hour.
How do I get back to exercising after being sick? You are feeling better. So, how do you get back to your exercise schedule? Make sure that you no longer have a fever. Easy does it, listen to your body, and start back gradually. If you have been fever-free for a full 24 hours and feel better, give it a try. Go for an easy walk. Take longer than you usually would to warm up, and if you begin to feel sick or overly fatigued, cut your session short. Ditto for overuse injuries.