The main reasons for this is that once we reach the age of 30, the muscles in our body begin to shrink because they are not being used correctly. Also our bones become much less dense over time. In some cases this may actually lead to a person suffering from osteoporosis. Unfortunately as our muscles begin to shrink so our metabolic rate also begins to slow down as well. its hard to keep the muscles and a flat body you had, However there are things a person can do when they reach the age of 40 which can help to prevent them losing muscle mass and keep their metabolic rate working at a good level. You have to follow the right kind of diet and use a good exercies.
below here you can find some tips wich are usefull.
It is important that you have a good well rounded set of exercises in your workout program. You need ones that are going to flex and stretch your body and also include some cardiovascular exercises as well. By including such a good set of exercises into your workout program the less likely you are to suffer from any kinds of injuries.
Never carry out the same routine each day, instead mix it up a bit. So one day go and do a session in the gym and another just go for a walk or bike ride instead. If you mix up your exercise regime more then the less likely you are to get bored with doing it and so the less likely you are to quit. Also by varying your workout routines the less likely you are to suffer any kind of injury because you are not overworking any sets of muscles too much.
Before you start any sort of workout it is vital that you carry out the right kinds of stretching exercises first. If you start working out whilst your muscles are still tight can spell disaster for you. Remember as you get older your muscles are not as elastic as they were when you were younger. Therefore by stretching before working out or just generally through out the day will help your muscles to regain and retain the elasticity in them.
These tips is the begin to getting fit again. and maintain that healthy body. But as I said this is just the basic