Plainly said, when we exercise consistently, our bodies adapt to that stressor by changing our muscle structure, metabolism, and physiology. It is that change, that remodeling, that leads to all the positive benefits of exercise. To stick with our banquet example, if we realized that 500 people are going to show up at every event, but we only have 10 tables set at present, we would change our capacity to be ready for the next event. We would increase the efficiency in the kitchen and set more tables. Likewise, our body remodels itself to adapt to increasing exercise.