When creating a great workout program,
you think set, reps, specific exercises.
Maybe if your going in deeper you
will think about nutrition and supplements,
But how often do you think about rest as being important.
A recent study shows that over training on consecutive days
can increase inflammatory markers and suppress immune function.
checkout the following abstract
High intensity workouts every day without rest days could impair immune system
It will make you think twice about the importance of rest in your program.