When you are experiencing symptoms of a cold or the flu, should you continue your marathon training or triathlon training as normal, do you need to cut back, or must you stop entirely? It all depends on the type and severity of your symptoms:
Conquering a Cold
Most experts agree that it is okay to continue exercising as normal when you have a mild or moderate head cold with symptoms such as sinus pressure, runny nose, cough and sore throat. But a cold that has moved into your chest, with symptoms such as chest congestion and tightness, is more likely to negatively affect your training—and if a cold negatively affects your training, then your training may negatively affect your cold! So in such cases, listen to your body and use common sense. If you are reasonably comfortable when you train despite your symptoms, and if training does not worsen your symptoms, go for it. Otherwise let discretion be the better part of valor and take a day off.
Fighting the Flu
Until recently there was virtually unanimous agreement in the medical community that one should not exercise while battling flu symptoms such as nausea, vomiting, fever, diarrhea, and body aches. Newer research, however, has called that dictum into question. For example, a 2009 study by researchers at the University of Iowa found that moderate daily exercise improved flu symptoms in mice infected with a flu virus. The key word here is “moderate.” Attempt only short, low-intensity workouts when you are experiencing flu symptoms, stop exercising immediately if you feel horrible while working out at a low intensity, and simply avoid exercise completely if you feel miserable even thinking about working out. So, as with colds, listen to your body and use common sense in deciding whether to train with the flu.
Protecting Your Immune System
While exercise generally strengthens the immune system, strenuous individual workouts such as long marathon training runs or lengthy speed sessions temporarily suppress immune function. Therefore you should also consider your training workload when trying to decide how to respond to symptoms of illness. If you’re feeling under the weather yet you’re training moderately, it is unlikely that you’re suppressing your immune system and making it harder to beat the virus. But if you’re in very heavy training, it might be best to cut back your workouts to give your immune system a quick boost so it can beat the virus instead of letting it linger and possibly affect your training for many weeks.
