To keep yourself healthy and fit you should do two general types of exercising – cardiovascular and strength training.

Cardiovascular exercise is activity involving the large muscles of your body such as your legs. The biggest benefit of cardiovascular is that it helps to keep your heart strong and healthy. It can also be helpful in losing weight.

Strength training exercise helps to build muscles. This helps to make you stronger and can help your joints also. Muscle tissue also uses a lot of calories so having stronger muscles can also indirectly help you lose weight or keep it off. Strength training exercise is especially important as you get older and start aging, as muscles will otherwise start getting much weaker.

To learn more you might want to start with this article: What is cardiovascular exercise?