Exercise & Immune Function

Being in a constant state of fear and stress seems to be the “new normal” for 2020. But are you aware of the effects that stress and fear have on your immune system? One thing that really helps me to disassociate from that state of stress and anxiety is exercise. I love doing CrossFit and lifting weights. The box is my sanctuary and it’s a place that I can go to and forget all my worries and troubles and just focus on the workout. It’s a place where I can completely be “in the moment”. 

I know, it doesn’t always feel awesome while you’re working out, but trust me, there are a ton more benefits than just losing weight and looking good! Exercising not only keeps your heart, bones, and joints healthy but it also helps to boost your immunity to certain infections and diseases, so you can continue to feel great everyday. 

We all know exercise raises your heart rate and increases your body temperature. But, did you know that the brief rise in body temperature actually helps your body to fight off infection and prevent bacteria from growing? This is similar to when you’re sick and you have a fever; that’s your body’s immune system kicking into high gear, trying to burn off any bacteria, viruses, or foreign substances in your body.

Now, let’s talk a little bit about inflammation. Acute inflammation, although painful at the time, is actually a good thing. Acute inflammation, in response to an injury, is a sign of a healthy immune system. Chronic inflammation, that’s the one that wears your body down over time. It can actually slow down the response of your immune system, making you more susceptible to colds and illnesses! Exercise helps to decrease chronic inflammation in your body and it also helps to increase your white blood cell production and  inflammatory response markers. For example, interleukin 6 is an inflammatory response marker, and it’s job is to help the body quickly respond to infections and injuries. The quicker your body can identify, respond, and defend against this, the quicker you can heal and get back to your daily activities and doing what you love. 

Nothing feels better to me than that “I did it” feeling after finishing a really tough workout. Exercising can relieve stress by releasing lots of feel good endorphins, which interact with your brain to help reduce pain perception. What better way to deal with the stress that 2020 has brought on to all of us than to have endorphins released directly into your bloodstream! When you’re feeling stressed, it causes your body to release hormones such as, adrenaline, dopamine, norepinephrine, and cortisol. In small doses, these hormones can help you in times of danger or while you’re in a fight or flight mode. They can also help to decrease local swelling and inflammation by blocking pain at an early stage. The problem with these stress hormones is when they are constantly running through your body. They can start to cause chronic inflammation, hypertension, and even put you at risk for a stroke. Stress hormones affect your immune system by lowering your body’s ability to make white blood cells. Exercise will actually slow down the release of those stress hormones into your body. 

I found a few recent research articles that I thought were very interesting relating to exercise and immune function. 

  • In 2019 a scientific review found that moderate-intensity exercise is linked to lower rates of upper respiratory tract infections, which includes viruses like the flu and common cold. 
  • In a study conducted in 2018, 1,413 people in China found that those who reported exercising at least three times a week reduced their likelihood of getting a cold by 26%.  
  • In another study conducted in 2018, 390 people found that those who were trained with an eight-week regimen of moderate exercise reduced their risk of acute respiratory illness by 14%, and their number of sick days by 23%, compared with people who did not receive the exercise training. 

What are some exercises that you are doing or that you can start doing during this pandemic? Exercise is a wonderful, addictive, feel good activity that has so many benefits to our health and wellbeing. It can literally add years to our lives. I love doing CrossFit and Olympic lifting, but I know that style of exercise is not for everyone. The best part about exercising is that there are so many options and ways that you can do it, the only real criteria for exercising is to move and raise your heart rate. That’s it. Working out doesn’t have to be this intense, heavy lifting, crazy long, marathon, cardio session for you to experience the benefits of it and the wonderful effects it has on your immune system. It can be something as easy as a 30 minute bike ride with your children, or a 20 minute walk during your lunch break. Yoga and barre are great workouts that you can do while at home. Having a buddy to keep you accountable can make it easier to exercise more often. Even if you can’t get together in person, due to social distancing, it’s still possible to have a workout buddy these days. You can call up a friend and go for a walk while you both talk to each other on your headphones or virtually watch the same video together and do the exercises. Whatever you decide to do, the most important thing is to stay active, stay moving, and try not to let stress or fear take over your day to day life. 


Barrett B;Hayney MS;Muller D;Rakel D;Brown R;Zgierska AE;Barlow S;Hayer S;Barnet JH;Torres ER;Coe CL; “Meditation or Exercise for Preventing Acute Respiratory Infection (MEPARI-2): A Randomized Controlled Trial.” PloS One, U.S. National Library of Medicine, 22 June 2018, pubmed.ncbi.nlm.nih.gov/29933369/.

Nieman, David C, and Laurel M Wentz. “The Compelling Link between Physical Activity and the Body’s Defense System.” Journal of Sport and Health Science, Shanghai University of Sport, May 2019, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523821/.

Zhou G;Liu H;He M;Yue M;Gong P;Wu F;Li X;Pang Y;Yang X;Ma J;Liu M;Li J;Zhang X; “Smoking, Leisure-Time Exercise and Frequency of Self-Reported Common Cold among the General Population in Northeastern China: a Cross-Sectional Study.” BMC Public Health, U.S. National Library of Medicine, 27 Feb. 2018, pubmed.ncbi.nlm.nih.gov/29486739/.

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