Second, fitness improvements will be somewhat similar whether the activity is continuous or intermittent. For many people, taking exercise in small daily doses rather than in one gulp improves adherence. Each session should consist of one set of eight to ten exercises that condition the major muscle groups of the arms, shoulders, chest, abdomen, back, hips and legs. Each set of repetitions should exercise the muscle group to near fatigue. If well planned, an entire session need take only about 20 minutes.
Resistance training is an important factor to total fitness.
If you don't stress your muscles, they will lose about one-third of their strength by age 75. Much of this decline occurs after age 50. Resistance training can significantly limit this loss. It can also help you regain lost strength quickly. This is important to avoid injury and to maintain suppleness with age.