Exercise As a Stressor

Sometimes your hormones might not seem to help you much in the psychological stress department, but they can help your body adapt to physiological stress. Researchers generally believe that the body goes through three stages when confronted with a stressor-in this case, exercise. The first phase is shock, represented in weight training as the delayed-onset muscle soreness you feel for several days after starting a new exercise or routine. In this phase your performance may actually decrease because of the soreness. The second phase is adaptation, which occurs as the body adapts to a particular training stimulus and starts to show improvement. The third phase is staleness, in which the body has already adapted to the exercise and is not showing further improvement. For example, if you have never bench pressed before, you will make significant progress when beginning this exercise. However, you will notice after a period of routinely performing this exercise that your gains will be smaller than they were in the beginning-that you've hit a plateau. The reason is that your body has adapted to the exercise with the benefit of your hormones and (as I mention earlier in this chapter) your nervous system. Now you either need to add weight, change the number of repetitions and sets, change the rest periods between sets, perform totally different exercises, change workout days, move the order of the exercises, or vary the exercise (for example, perform an incline bench press instead of a flat bench press) in order to again see performance benefits.