Are you experiencing knee pain?  It’s common.  It might be that you just need to let your body recuperate a little, maybe sit in a hot tub before you workout, maybe take one day’s rest or a few days rest per week between workouts, maybe just switch between upper and lower body between days to give your knees a break in general terms.  This works for most people.  But the simple fact is that your joints may also be breaking down over time.  So this is definitely something worth considering. 

You may want to start taking a joint supplement of chondroitin and glucosamine just in case.  That is just one of those things that may actually help you out in the journey you are taking.  But also you may want to look into that, because plenty of people experience arthritis, many people who exercise in general break down their knee joints specifically over time.  It happens to the best of us.  It’s just a matter of keeping all the possibilities in mind and therefore considering all the possible solutions.  This will help you to ease your joint pain in many cases while actually keeping up your exercise routine as a general rule.