Upper respiratory infections (including the common cold) are sudden-onset infections impacting the sinuses, throat and nose, and they’re usually caused by airborne viruses. We’re constantly exposed to them, but normally our immune systems keep them at bay. Depending on intensity, exercise such as a fun run can have either a positive or negative effect on your immune response.
If you’re leading a sedentary lifestyle, your risk of catching a cold is average (that equals two or three colds per year). Studies show that people who engage in moderate-intensity exercise at least 5 times per week (like a brisk walk) can lower their chances of catching a respiratory infection by about a third.
The beneficial immune effects are the result of the cumulative impact of the lower-intensity exercise, but the opposite is also true. In times following strenuous exercise—like the days after a 5k run—people have up to six times the likelihood of getting sick. Heavier training loads make you more susceptible to the common cold; you might end up missing more training sessions than if you’d just taken a day or two to rest.
Mounting research shows that exercising at a high intensity for more than ninety minutes a session can make you more vulnerable to illness for up to three days afterward. If you’re an avid trail or marathon runner, your workouts may cause a temporary dip in immune response. During intense workouts, your body produces immune-dampening hormones (adrenaline and cortisol). If you’re training for your next race, follow these guidelines to reduce your chances of catching a cold or the flu.
- Eat a balanced diet. Your body’s immune system depends on a variety of minerals and vitamins to function as it should; there’s no evidence that over-supplementation will be of any benefit.
- Don’t try to lose weight too quickly. Extreme calorie-reduction diets, fasting and too-fast weight loss are all proven to reduce immune response. Losing a great deal of weight combined with intense training is a double impact.
- Get enough sleep. If your sleep is often disrupted (meaning you get 4-5 hours per night) you’re more likely to have a suppressed immune system). If you’re training hard, make sure you get your rest.
- Don’t overtrain. Properly space out your races and long runs as much as possible. Don’t get too fatigued and don’t push your body beyond its limits.
Regular, moderate intensity exercise can bolster your immune system and reduce your risk of catching an upper respiratory infection, but running and other strenuous exercise can make you more vulnerable. For best results, strike a balance between training, nutrition and recovery.
This guest post was written by Amy Fowler for The Poppy Run, who organise 5k runs on behalf of The Poppy Appeal.