For the most part, exercise keeps the immune system healthy. In most cases, the average exerciser with a routine that consists of short bouts of moderate-intensity exercise has a stronger immune system than someone who is mostly sedentary. However, the same doesn’t always hold true for endurance athletes like marathon runners and triathletes who train at high intensities for prolonged periods of time.
Some research reveals that the immune system’s ability to effectively fight off infection immediately after (especially within the first 24 hours) prolonged periods of high-intensity exercise is weakened, making the athlete more vulnerable to illnesses. In particular, endurance athletes may be most susceptible to upper respiratory tract infections. Plus, exercise is just one form of stress for our bodies. We all have other sources of tension in our lives, which can also contribute to reduced immune function, mainly due to an increased production in the hormone cortisol.
So, as the fury of the flu starts to take full force and with marathon season in full swing, how can endurance athletes continue to train without running the risk of totally taking down their immune systems?
Avoid Overtraining: One study showed that athletes who trained beyond their body’s capacity (which is defined as, "periods of intensified training that result in overreaching") chronically reduced the health of their immune system, even past the first 24 hours after the exercise bout. This emphasizes the significance of having a well-planned training strategy that includes plenty of rest and recovery time and that meets the specific needs of your athletic abilities, as well as the importance of listening to your body and modifying your plan as needed.
Get Enough Good Sleep: Sleep deprivation studies have shown that lack of sleep can hinder the immune system’s ability to function optimally because important immune processes happen during certain stages of the sleep cycle. Plus not only will getting to bed on time help make your body better able to fight off the flu, but it will also ensure optimal performance while training, too.
Don’t Rely on Supplements: There’s little to no evidence that supports the supposed benefits of things like antioxidant vitamins, glutamine, zinc, and similar products that promise to enhance performance and boost your immunity. The American College of Sports Medicine states that “Vitamin and mineral supplements are not needed if adequate energy to maintain body weight is consumed from a variety of foods.” In other words, fill your diet with whole foods that can naturally provide your body with the vitamins and minerals it needs to maintain optimal immune and overall health.
Fuel Your Workouts Properly: The same study that revealed a weakened immune system following high-intensity endurance workouts also found that the effect was most pronounced when the athletes had not eaten prior to the exercise session. Be sure to maintain a balanced diet that includes lean proteins, healthy fats, and of course, quality carbohydrates, which help maintain blood glucose levels and supply fuel for your muscles.