Training for a marathon is a process of precision that requires strict adherence to schedule and timing. There is not a lot of room for illness in the marathon training schedule, especially when it is prior to race day. Added to this is the probability that you will likely get sick while training for a marathon since the endurance demands on the body can cause immunity to wear down. Fortunately, it is possible to push through sickness to continue training (or at least maintain it) as long as precautions are taken.
Sickness is not the End of the World
Training for a marathon requires physical demands on the body that took the life of the first runner to attempt the distance. However, runners have since perfected the training and balance of nutrition required to undertake the feat that is the marathon. Still, the body can respond with illness and this must be managed with care. Training for a marathon while sick is a definite possibility, one that I have undertaken myself. The key is hydration, rest between workouts, proper nutrition and pushing yourself only as far as you should for how you feel.
Be Realistic and Take it Easy
Monitor your capability to work out by how you feel and what the numbers say. If, for example, you have a fever over 100 degrees, you should not be running. Running will raise the body temperature and put you at serious risk. You do not want to risk sitting out for a week when you could simply sit out for one or two training runs. If you do not have a high grade temperature, feel free to take a light, easy run for maintenance. You should not be doing speed work, hill work or anything requiring your body to divert its energy from healing. However, getting out and moving can help you on the road to recovery.
Hydrate, Hydrate, Hydrate
The other thing to remember when training for a marathon while sick is to hydrate, hydrate, hydrate. I cannot stress the importance of this enough. Cold medicine and fever will cause your body to lose fluid faster than normal, and it must be replaced if you are to continue training during illness. Water is often the best remedy for hydration needs, along with water-rich foods such as soups, vegetables and fruits. Vitamin C is also important to take during your training, whether you are sick or not. Recovery while training must be treated with nutritional supplements to prevent setbacks that stand in the way of progress through your marathon training program.
Do Right by Your Body
Some sites (and physicians) will recommend taking a complete break from running while sick. This is determined by the illness and its severity, as well as by the training demands at the time of illness. If you are at the beginning of your training it will be a lot easier to postpone it for a week, just as it would be during a time of tapering. If you are in a crucial mileage building phase, this can have detrimental effects on your marathon readiness. It is imperative that you take this into consideration and above all else, do right by your body.