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5 Keys to Boosting Your Immune System

By: Caroline Daniel

In the middle of a global pandemic, it’s likely that you have recently become much more aware of the many traditionally “normal” activities that can actually increase your risk of getting sick. In fact, if you’re like me, you’re probably much more aware of your overall health in general–any sniffle or tickle in your throat makes you feel uneasy–what if it’s COVID? In this week’s blog post, I hope to put your mind (at least a little bit) at ease by showing you how you can best be taking care of your body to decrease your chances of getting sick–and if you do get sick, to hopefully decrease the duration and severity of the illness. 

  1. DIET

As you probably know, a healthy, balanced diet will help your body to function most effectively and efficiently on a daily basis; however, there are certain foods to incorporate into your diet that are beneficial to your immune system. Specifically, foods with high amounts of vitamin C are pivotal, as your body doesn’t produce or store vitamin C. For this reason, it is very important to ingest adequate daily amounts of vitamin C. Here are some foods that are great sources of the immune-boosting vitamin:

  • Citrus fruits
  • Spinach
  • Broccoli 
  • Red Peppers
  • Papaya
  • Yogurt (not loaded in vitamin C, but contains live and active cultures that can help stimulate the immune system to fight disease)

A 2019 scientific review in the Journal of Sport and Health Science concluded that regular, moderate exercise can improve your immune response, reduce inflammation, and lower overall risk of illness–in addition to improving your overall mental health. Studies have shown that “acute exercise” – meaning moderate to vigorous intensity exercise performed for an hour or less – increases your body’s circulation of immune cells. As these immune cells circulate to areas they normally do not reach, they are able to wipe out pathogens. This increased immune cell circulation has even been seen hours after an exercise session and can built up over time if you consistently exercise throughout the week. 

In order to find the best intensity to improve your overall immune function, aim to reach around 60-70% of your VO2max–but, since most people don’t know/can’t track this value easily, aim for around 65-75% of your max heart rate, which can be predicted based on your age and activity level (or by using a heart-rate tracking watch or strap). 

  1. SLEEP

According to healthline.com, “when it comes to your health, sleep is your armor.” Research through the years has shown repeatedly that people who are sleep deprived are both more likely to get sick after being exposed to a virus and more likely to take longer to recover after contracting an illness. Clearly none of us wants to get sick, but nonetheless about half to two-thirds of the US population is sleep deprived. 

Research shows that people who sleep less than six hours a night are four times more likely to catch a cold compared to people who consistently log seven or more hours of sleep. But why? When you sleep, your immune system kicks into high gear. The immune system requires a lot of energy to power its activities, so while energy demands are reduced during sleep, the immune system can act without interruption from digestion or movement. It releases proteins called cytokines, which help promote sleep and fight infection and inflammation. 

I know it’s difficult to put down the phone and turn off the TV after a long day–but that extra hour or two of sleep could make all the difference in your body’s ability to recover and fight infection. 


Recent research in the field of “psychoneuroimmunology,” a burgeoning field investigating the effects of state of mind on overall health, has shown that stress weakens the immune system. When you are stressed, your body produces higher levels of cortisol, a corticosteroid that decreases the immune system’s effectiveness by lowering the number of lymphocytes present in the bloodstream. Additionally, when a person is stressed, he/she is more likely to engage in other behaviors that may lower the immune system’s efficiency–smoking, drinking, lack of sleep, drug use, etc. 

But how do we remain unstressed in the current global climate? If you’re feeling more anxious than normal, I recommend starting by taking a quick break from the information overload. Turn off the news or delete a social media app. While it is important to stay informed, constantly hearing negative news will ultimately hurt us more than helping us. Instead, focus on positive activities like exercise, journaling, cooking, or whatever hobby makes you feel happy and relaxed. Not only will you be happier, you’ll likely increase your body’s ability to fend off illness.


Hydration is a key element to maintaining a healthy immune system that is often overlooked or forgotten. The immune system is highly dependent on the nutrients circulated around our body by our bloodstream–and the bloodstream is made mostly of water. This means that if we do not have adequate water in our bodies, we cannot efficiently transport nutrients to each organ system. Additionally, hydration is pivotal for detoxification–the water in our bloodstream ensures that we are able to clear out foreign invaders and other wastes. 

Many doctors recommend that their patients drink a minimum of half of their body weight in ounces of water. Meaning if you weigh 160 pounds, you would drink a minimum of 80 ounces of water each day. This number should only increase if you engage in vigorous physical activity or consume caffeine and/or alcohol. In addition, during a hot Nashville summer, it is important to consume plenty of electrolytes–try adding a light or watered-down sports drink to your post-exercise routine to make sure your body is hydrated with more than just water–and is ready to fight off illness as effectively as possible!

Caroline Daniel is a Student-Athlete running Cross Country and Track at Belmont University while Majoring in Exercise Physiology. She is currently completing her internship at Personal Best Fitness