I'm slowly trying to get back into shape again and can only reiterate what Alan has said. Start slow and light! Once in our 40's, we need a bit more time to recover and rebuild. I started out too fast and too hard, and paid the price. Lost a lot of time recovering. Things get hurt a little easier, and they heal a little slower, but it can certainly be done!

It's a sad realization when it hits you that you just ain't 25 anymore in the weight room, but that is replaced quickly with pride that you are doing it when the results start coming in.

Do it... just do it a tiny bit slower