Explain why exercise programs must increase in difficulty and duration over time to remain effective.

Exercise programs must increase in difficulty and duration to remain effective because of the principle of overload. As an individual exercises at a higher level, the body adapts to the increased demand and this higher level eventually becomes your body's new normal.

Explanation:

wellness is the state of being in good health, especially as an actively pursued goal.

hey jade its kaitlyn do u know ethan luttrell