No ,I'm not taking any meds...sometimes I feel tired when I'm biking ,I don't give it my all ,but yesterday when Darcy ,and Oxyback (Ellen) ,and I rode, we all stayed together ,and did go up against headwinds ,and hills. I wasn't out of breath or anything ,but I did give it my all. I don't think anything is wrong with my HR monitor ,as I ran 2 miles to test it ,and my avg HR was 132 for 18 minutes? I'm going for a short 15 mile ride now ,and I'm going to try ,and work real hard. I just don't understand why all of a sudden it has dropped so low.