Exercise programs and personal training are often said to reduce stress, but what's the truth?

There are immeadiate results but the real benefits are the long term effects:

Increased cardiorespiratory function and decreased body fat cause you to be less stressed during the day. With increased fitness levels, physical activity itself becomes less of a stressor. Studies have shown that as a person becomes fit, he/she can do the same amount of work with LOWER heart rate, blood pressure and adrenaline. The energy necessary to accomplish a task remains the same but the stress response is reduced.