When I got back on my bike after too many years I weighed 280 and had a hard time getting up and down our home's staircase. On the bike I went anaerobic at about 127bpm. I'm 60yrs old. I'm now down 50lb (gained 10 over winter but we won't talk about that). Tonight at spinning class (after a 30 mi ride) I held a heart rate of 158 for about 45min. Up till tonight I considered 153 to be my anaerobic threshold. My AT has gone up (as has my max heart rate) slowly but surely over the last year and a half. Being able to hold 158-160 was quite a big deal for me; those of you that are getting back to,or starting riding to help lose weight and get in better shape...keep at it. It doesn't happen over night and I still have 30lb or so to lose before I'm almost satisfied, but that will come this summer, I hope.