Does aging cause energy loss?

There are small but definite changes that happen in your body as you age. For example, did you know that once you hit 40, you cannot get into the deeper, more restorative stage four sleep? Also, after age 30, muscle mass starts to decline unless you use it. But these changes account for only a small loss of energy, and many (although not all) of these changes can be prevented or minimized with a healthy lifestyle. Exercise is an excellent way to lift energy levels.