Answer:
exercising more than you normally do improves fitness
Step-by-step explanation:
The "Principle of Overload" is all about gradually increasing the workout load in order to improve a person's fitness. This is the only way for your body to adapt. This is the reason why you have to do variety of exercises and not only focus on one type with the same intensity and duration because it may lead to a "plateau." A plateau prevents any improvements.
Thus, if you exercise more than you normally do, then you're definitely improving your fitness in a gradual way. Overloading follows the FIIT Principle (Frequency, Intensity, Time and Type).