Slow the Aging?

It's a given that exercise helps us look younger and stronger on the outside,  (I noticed myself in the mirror at the gym yesterday and made the comment to my DD:  "WOW-Your Mom sure has some guns!" LOL!  In just a month's time-I am seeing a lot of improvement!) but what does exercise do for our insides?  Research has proven that exercise can help prevent aging at a cellular level and over a period of time, exercise helps us to maintain good cellular health, helps with arthritis in the joints by improving movement, promotes good bone health and of course keeps our heart healthy and lungs functioning properly-(you gotta remember to keep breathing.) 
It is still a good idea to work out safely-I, for one have osteo-arthritis in my knees, ankles and elbows-while the ankles and elbows have improved now (without meds)-I still have to be careful with my right knee and right elbow.  I upped my workout weights the other day and immediately decided that wasn't such a good idea and dropped back to a safer weight.  I would much rather do more reps than take a chance of getting hurt in a joint by pulling or damaging a tendon.  (I started with 2 lbs and moved up to 3 lbs and moved up to 5 lbs-but can't go to the 10's-it's just too much stress on the elbow joint.  This is hand-weights-on the machines, weight varies depending on the machine, but I'm still below 50 lbs.-but doing 4 reps instead of 2 now.  I've built up to this very slowly over a month's time-don't rush it!)
Another thing-doing lunges with a knee that doesn't want to work is no fun-what I do for added support and safety is-I take apart my broom and use the handle for added stability.  This helps me to bend the knee and get back up without adding undo pressure to a weak knee-yet it allows me to do the full workout.  Eventually, I may not need that broom handle-but it gives me a sense of security-knowing I'm not going to hurt my knee and be off my feet for months!  (This is when I'm working out at home-in the gym I will skip this part of the class and do stretches or work my abs instead.  Don't be afraid to do your own thing-you don't have to follow the class!)
The moral of the story is-get to work but work safely and check out that mirror once in awhile!  :-D