We’ve all had a cold or the flu at some point. Among the numerous benefits, you’ve likely heard that exercise can help the immune system fight off illness–there’s some truth to it. However, the benefits depend on the level of activity. Research shows that regular exercise at a moderate level supports immune function better than being sedentary…but overtraining can actually impair our ability to fight off infection.
Read on to learn how too much exercise can backfire.
The Benefits of Exercise on the Immune System
Research shows that the right amount of exercise boosts immune function. One study of 500 adults found that those who exercised at a moderate intensity for 1-2 hours a day had a reduced risk of contracting an upper respiratory tract infection (URTI). Numerous studies also show that people who exercise regularly take fewer sick days at school and work. Exercise has also been shown to improve mood and mental function.
How Does Overtraining Weaken the Immune System?
Viruses and bacteria are everywhere. We encounter them at work, on public transit, at the store, in the park, and in our homes. The immune system works around the clock to fight off these microscopic invaders. Ironically, the immune system’s greatest enemy is often the very person it’s trying to protect. Too much stress, coupled with inadequate rest, weakens immune function. Overtraining usually encompasses both of these factors, making us more prone to harmful microbes that lead to colds and other infections.
White blood cells are the soldiers deployed by the immune system to fight off foreign agents. Prolonged bouts of high-intensity exercise cause the body to release adrenaline and cortisol into the bloodstream, both of which hamper white blood cell function. The more strenuous and sustained the activity, the more the immune system has to work, leading to a higher chance that is weakened. And since exercise requires more frequent and deeper breaths, we tend to inhale more microbes when working out, increasing the risk of infection. While proper rest and nutrition can restore immune function, overtraining can still take its toll.
Keeping a good balance between exercise and rest/recovery is important in two ways: 1) our immune systems not only work to prevent us from getting sick, they also help us in the times that we are injured, and 2) the less rest and recovery our bodies get, the more likely they are to get injured!
Most of us exercise to become stronger and fitter. However, if we barely let our bodies rest, then we don’t give them a chance to rebuild.
How to Recognize Overtraining
Studies show a link between regular moderate exercise and a reduced frequency of microbial infections compared with prolonged inactivity. However, overexercising can actually harm immune function more than being sedentary. Overtraining syndrome (OTS) is a severe condition that significantly limits a person’s physical and mental readiness. Of all the physiological process that suffer as a result of OTS, the immune system is particularly compromised.
Telltale signs of overtraining include elevated anxiety, excess muscle soreness, and joint discomfort, injury, dizziness, trouble sleeping, mental fog, and weakness. If you regularly experience more than one of these symptoms after exercise, consider adjusting your workouts.
In addition to the above characteristics, not seeing any progress in your fitness, strength, or skill development–whether it be a plateau or a decline–is a good indication that you need to let your body rest and recover.
How to Prevent Overtraining
Training the human body is much more complicated than leveling up a video game character. A sustained period of high-effort training with minimal rest takes its toll physically and mentally. Athletes who push beyond their limits day in and day out are often left drained and anxious at competition (as well as in daily life) as a result of a compromised immune system. Knowing how to avoid overtraining is just as important as training hard:
- Warm-up adequately before exercising, and cool down and stretch afterward.
- Get adequate sleep between training sessions. The harder you train, the more rest you’ll need to continue performing at your best.
- Maintain good hygiene.
- Wear comfortable, breathable clothing and proper footwear.
- Stay hydrated.
- Eat nutritious foods. Athletes need more vitamins, minerals, protein, and healthy fats than the average person.
- Take time to de-stress: meditate, listen to music, and do fun activities outside of training.
- Exercise at a level appropriate to your physical capabilities. Don’t try to do too much too soon.
Work with a knowledgeable coach/trainer who can help you train at the proper intensity.
You can have too much of a good thing, and exercise is no exception. Fortunately, it’s possible to train hard and train smart. Keep the above tips in mind to help your immune system help you.