Should you run with a cold or other illness?

Colds and illness affect all of us at one time or another. Knowing how to deal with them is critical.

Should you run with a cold or other illness? How does running affect your immune system? Does it make it better or worse? The answers to these questions are as complex as the human body itself, but there are some simplified guidelines that can help in most situations. Only use these guidelines if you feel well enough to train and want to train; if in doubt, avoid exercise and rest up.

Training Style	Mild Cold	More serious infection
General fitness and health (light training, but no speed work or endurance training and never exhaustive.)	Train as normal if symptoms are 'above the neck', otherwise reduce the amount of running.	Reduce the amount of running.
Structured training (Specific speed and endurance training, but not pushing your physical limits.)	Avoid exhaustive training during cold. The risk of Overtraining Syndrome is slightly elevated.	Exhaustive training should be avoided for a month after infection. Curtail the intensity and/or length of harder workouts. The risk of Overtraining Syndrome is moderately elevated.
Competitive training (Pushing the boundaries of your physical capabilities.)	During the cold avoid exhaustive training and reduce the intensity and volume of training. The risk of Overtraining Syndrome is moderately elevated.	Exhaustive training should be avoided for a month after infection. Significantly reduce the intensity and volume of training while symptomatic, ramping back up afterwards carefully. The risk of Overtraining Syndrome is significantly elevated.

Important note: chest pains (especially stabbing pains) or unusual shortness of breath may be symptoms of Myocarditis, a potentially fatal condition.

1 Running with a cold or other illness

The common cold (often called Upper Respiratory Tract Infections or URTI in research) is one of the most common problem effecting athletes and some claim it causes more problems than all other illness combined. However, there are other more serious infections that should also be considered.

• Exhaustive exercise compromises the immune system and can make an existing infection worse.
• Light exercise while suffering from a mild infection is generally believed to be safe. There is a widespread medical opinion that it's okay to run if the symptoms are all 'above the neck', but there appears to be little or no research to back up this belief.
• Even a mild infection adds to the overall stress levels and increases the risk of Overtraining Syndrome. In addition, an infection may be a symptom of Overtraining Syndrome.
• Infection from Rhinovirus (the usual cause of the common cold) does not affect exercise performance. However, it can be tricky to know if an infection is due to the Rhinovirus or some other agent.
• Some infections, such as those involving inflammation of the heart (myocarditis), can be potentially fatal when combined with exercise.
• Many infections will reduce performance, sometimes dramatically.
• Exhaustive training should be avoided for a month after infection, except for mild common colds .

2 Avoiding Infections

• Be aware of the factors causing Overtraining Syndrome, as this can result in a compromised immune system. Factors include life stresses, diet, Training Monotony, and adequate sleep.
• Avoid touching your eyes or nose without first washing your hands, as this is a common route for infectious diseases.
• Where possible keep away from sick people and large crowds when your immune system is likely to be weakened.
• Exhaustive exercise compromises the immune system and can make the athlete more susceptible to infection. Taking carbohydrate before during and after exhaustive exercise can reduce the suppression of the immune system.
• Be particularly careful after exhaustive exercise, including racing.
• Monitor Mood State, as this is can be an indication of reduced immune system functioning amongst other things.

3 Running and the immune system

The risk of infection is 'J' shaped in lower fitness people, but as fitness rises, the risk goes down, but does not completely flatten.

There is a general belief in a 'J' shaped relationship between exercise level and risk of infection, but it seems that the shape depends on the level of fitness. Lower fitness individuals' immune system benefits from some exercise, but as the intensity rises, the immune system benefits decline.

4 Racing and the immune system

Races up to and including the half marathon do not have an increased risk of infection, but the risk is significantly higher after marathon and ultramarathon races. However, there is some evidence that those experiencing an infection after the marathon distance may be due to a reoccurrence of symptoms from an earlier infection.

5 Nutrition and the immune system

There are various supliments that may help improve immune system functioning in runners.

• The amino acid glutamine is required by some parts of the immune system(lymphocytes) and exercise depletes blood glutamine levels . There is some evidence that glutamine supplementation is effective at reducing the immune system compromise.
• Vitamin C has been shown to reduce the incidence of UTRI by half. The doses used in the studies were 600mg or 1000mg daily. However, other studies have failed to show a benefit.
• Adding Vitamin E to Vitamin C supplementation does not appear to further enhance the benefit of Vitamin C. However, there may be other benefits from the combination of Vitamin C and E together, such as reduction in the risk of Alzheimer's disease.
• There is some evidence that probiotics (e.g. live yoghurt) prevents or reduces the intensity of UTRI symptoms. However, this benefit was not seen in other studies , nor did probiotics show a reduction in allergy or asthma symptoms .
• Tea, especially green tea, contains Theanine which may help reduce the immune system depression of high intensity training.
• Taking carbohydrate before during and after exhaustive exercise can reduce the suppression of the immune system.

6 Other treatments

• For colds (upper respiratory tract infections), sinus flushing may help reduce the symptoms.