If I increase the intensity/frequency too quickly, then my arthritis acts up. Try increasing the intensity just a little and work at that level until your body is accustomed to it. Or try increasing the duration by a few minutes at a time, depending on what kind of exercise you are doing.
It takes longer to progress this way, but it's better than having to take breaks in between.
Hope this helps...
Do or don't do; there is no try (Yoda)