I just had a UTI last week. Unfortunately, it did start to affect my kidneys because I didn't recognize the symptoms early on. Within hours of taking the antibiotics, I started to feel better. I only took off one day of cycling. It never dawned on me to ask my doctor about exercising. I only took off that one day of cycling because I was in so much pain that sitting on a bike would not have been very comfortable. But like I said, once I started taking the meds, I felt 100%. Good luck...hope you feel better soon.