It is an understatement to say that training for a marathon is a challenging task. The long distance workouts involved present special demands on the body, and it is no wonder so many runners become ill or injured. Consequently, one of the goals during heavy training, for both beginner and professional, is to stay healthy. No one likes seeing all those months invested go to waste. The two main areas that get runners into trouble are a run down immune system, and musculoskeletal injuries, both from overdoing it.

The immune system has a training effect, similar to other areas of physiology (e.g., cardiovascular, muscular). In other words, a balanced training program of exercise and rest leads to better performance. Too much training, however, causes a temporary decline in immune function, which can lead to frequent or prolonged infections. Viral upper respiratory infections (URIs) --e.g., colds and the flu -- are the most common type of illness that occurs, but there are also many others which can affect runners.

The relationship between exercise and susceptibility to illness is best described by the “J” curve. Couch-potatoes get approximately 2 - 3 URIs per year, whereas overtrained athletes can easily double or triple this number.

Obviously, one would like to build up the marathon training while staying in the “moderate” zone, which has a reduced risk of illness. Although the goal is clear, the reality is far more hazy because training is defined in relative terms. What is moderate for one runner may be overtraining for another. There are no set points etched in stone for which to define the various training zones. Also, because the immune system constantly changes and adapts, a runner cannot always rely on last years training log to predict success or failure this year.

Similar to the immune system, the musculoskeletal system can be nurtured and strengthened by a well balanced training plan. The other side of the coin is true as well; too much training, with inadequate rest, leads to injury. Running subjects the bones, joints, muscles and tendons to stresses which weaken them, but during rest the body repairs, and then adds a bit more for insurance. Over time these structures gradually become stronger. If, however, the training plan contains too much running, the repair process that occurs during rest may be insufficient. In this case, some components of the musculoskeletal system gradually weaken. Ultimately, an injury will result. Once again, the key is to stay below the overtraining threshold.

To help keep you healthy, and in a balanced training range, here are a few tips,

  • Keep a training log. In addition to recording workouts, keep a fatigue score (scale 0-5). It is expected that a hard workout will make you tired, so it is more important to note the cumulative "feel" during the day. Granted, the scale is individualized and subjective, but this simple tool is very useful. If you notice that your fatigue is progressively increasing over days or weeks, then it is time to add more rest.
  • Listen to your body. Pay attention to sore areas and intervene before an injury develops. Recording a pain scale (0 - 5) is a good way to monitor injuries -- and potential injuries.
  • A properly constructed training program that allows for rest and recovery will help head off problems before they start. Periodization is a way to achieve that goal.
  • Record your resting morning heart rate. A progressive increase may tip you off that you are exceeding your ability to recover.
  • Anticipate added stress in advance (e.g. new job, moving, final exams, etc.) and adjust the workout schedule accordingly. A small amount of rest early will prevent a bigger problem later on.
  • To make sure your anti-oxidant defense system is tuned up, eat five servings of fruit or vegetables per day. Note: vitamin supplements do not appear to have the same benefits as fruits and vegetables. However, if you wish to supplement, then vitamins E (100 I.U.), and C (250 - 500mg) can be added to the daily routine, and may be beneficial -- especially in the 2 weeks leading up to, and following, a big race.
  • Heed your body's early warning signs,
    • Disordered sleep (too much or insomnia)
    • Loss of interest in pleasurable activities
    • Moodiness or depression
    • Excessive muscle soreness
    • Poor concentration. Lack of mental energy.
    • Altered appetite.
    • Frequent injury or illness
    • Lack of physical energy
  • Get an annual influenza vaccine (usually available each year starting in October)
  • Because frequent URIs or unrelenting fatigue may be a sign of an underlying illness, it is recommended that you consult your physician.