Rest days are important because they allow the body to regenerate from exercise.


The irony of exercise is that it has a positive and chronic health benefit but it has an acute and degenerative effect on muscle cells. Sometimes the degeneration is caused by the trauma of an injury. Other times it caused by extreme temperatures, disease or excessive stretching. The most common cause is the exercise itself.

During a workout, the involved cells will break down—degenerate—from the strain and stress of the exertion. If the exercise is severe enough, the cell may even be destroyed. Do you strength train? Those reps and sets cause the muscle cells to tear apart. That’s the case for just about any vigorous exercise. The cells are cooperating with you, but in so doing, they’re emptying themselves.


rest days from gym

During recovery, the cell regenerates. The cellular materials begin to return. What does that mean?

Muscle cells, which are also called muscle fibers, are soft and fragile. They contain a number of even softer and more fragile parts, like myofibrils, myofilaments, sarcomeres, the sarcoplasmic reticulum, and the sarcolemma. Any of those delicate structures can become damaged during exercise. The damaged stuff is what gets repaired during rest. The repair process is called regeneration.

With adequate regeneration, a cell can end up with even more materials—more structure—than it originally had. That’s one of the main goals of training.

With inadequate recovery, the cells don’t regenerate enough before the next workout. That’s why rest days are important.

To be sure, it is not reasonable to expect complete regeneration of all the cells involved in an exercise. The time-course for cellular regeneration may differ from muscle group to muscle group, and perhaps even from cell to cell. By the next workout, the process of regeneration is not likely to have been completed for all of the involved cells.

Which means that the reality for exercisers is that we exercise in the presence of some number of degenerated muscle cells. Rest days are important because keeping the number of degenerated cells low is important.

Some gyms close for a day because rest days are important

The Training Station Gym is closed on Sundays and, every week, a number of members thank us for that. They say the rest did them good.