When you mention the term bodybuilding it often promotes the image of huge bulging muscles on a man or woman and then it is often associated with steroids or some other enhancement drug. Truth is very few bodybuilders use drugs and instead rely on hard work and excellent diet and nutrition to achieve their results.
So if you are beginning bodybuilding and over the age of 40 the first idea you need to get out of your head is huge monster muscles and other ideas associated with hardcore competitive bodybuilders. Using bodybuilding as your fitness tool is an excellent idea and there are countless studies that show your decision is the right one.
The first order of business is to take stock of your physical shape and it would be wise not to kid yourself. A visit to your family doctor would be a good start and he or she would know what kind of shape you are in and would advise you as to your approach. However the bottom line is you still have to do the work.
It is good practice to start slow when approaching the weights and always begin with stretching exercises before lifting any weights. As for the weights start real light and work your way up to heavier weights when you feel more comfortable and have spent some time in the gym.
It might be tempting to just start blasting the weights but it will only be counterproductive because your muscles are going to be so sore you won't be able to work out the next day or several not to mention it will not be good for your motivation.
If you can afford a personal trainer by all means that is the ideal way to approach your fitness goals. Do not look at the guys or gals in the gym and try to follow what they are doing because they might have been on a program for a long time and you will only end up hurting yourself and sabotaging your efforts.
Beginning bodybuilding over 40 is really no different than if you were 20, the difference is the recovery time and the rate of muscle growth. You can build muscle mass over 40 however you are not going to get the gains like you would if you were 20 years old, so it is wise to set realistic goals and never give up!