Many people think that they are gaining fitness while they are working out. They feel that while they are lifting weights in the gym, or riding their bicycles, climbing on their stair steppers, or walking out on the road that the adaptations to exercise occur during their time of activity. Once they are done with the workout they can move on and go right back to their hectic life and poor diet and as long as they continue to exercise on a regular basis they will reap all the benefits of the workouts. Well, that just isn't the case. As I lecture to my students each semester at Occidental College, write about in my sports nutrition book Fuel Up, and repeat to my clients at every opportunity - not only is exercise a stress but it is not during exercise that you gain fitness. The gains in strength, cardiovascular (aerobic) endurance, flexibility, power, and other fitness measurers come in the time period between workouts. The true adaptation provided from exercise comes when you get adequate rest and proper nutrients for repair and growth. While exercise, and stress, are a critical component to the equation, it isn't the whole equation. Creating the stimulus for fitness gains is only the initial step in the process. The type of exercise you perform will determine the nature of the adaptation - will it be an increase in muscular strength, will you gain greater flexibility, will you improve your aerobic capacity? But those changes only come about after your body has recovered from that stress, and that takes time. Without rest and proper food, your body will break down and not benefit from your workouts. If you train too hard and / or don't get enough rest and adequate nutrition your body breaks down rather than builds up. Just like any other form of stress - if you can't respond to it, your body deteriorates and you get injured, sick, or lose motivation. Moderation, slowly building up the duration, frequency, and intensity of your workouts, along with varying the overload of those workouts are essential to continued improvements rather than set backs. But improvements only come with proper nutritional intake and adequate rest, sleep, and time for repair. So treat exercise like it is - a stress. An essential one in life - in you want health and independence - but a stress none the less. To reap the maximum benefits from your workouts remember all the components of the fitness equation and make sure you eat an optimal diet and get adequate rest before starting your next workout session. | 
