Was on them after the bypass and my max HR went from 165 to 130. At 130 I was in trouble and no matter how hard I pushed- I Could not get above that. The 130 felt around 170 so that was how hard it hit. I had to get out on the bike though as it was part of my recovery plan so I rode miles with the HR not getting above 120. Had a chat with the doc and instead of taking the BB in the morning of a ride- I took it the night before and then 1/2 a tablet after the ride.

13 weeks after the bypass I did a 40 mile ride. Couple of steep hills involved and the first one I took it steady on the 5% for a mile approach but on the 400 yards at the end where it steepened up I had to put in effort. Saw 160 so recovered afterwards. Bit later on and I got riding with a lad on a wallymart Full suspension bike. I was on a mountain bike with slicks and he got telling me that the only way to mountain bike was full suspension and I got fed up with him. Next hill and as he flagged I put the power in and left him. I knew there was an ambulance at the top so if I had any problems there would be help close by. Saw 165 and went and rested by the ambulance. Took a long time for the HR to drop to 110 and the ambulance crew got talking. They were waiting for the heart attack to happen as last year there were 2 on this hill. When I recovered I told them I was getting over a Bypass and I think they panicked.

Got riding again and finished the ride. Loaded the bike in the car and sat down to take off the shoes. Stood up and agony- I had Shin Splints and just could not walk. Hobbled to the car and took the 1/2 BB and went home none the worse for wear- except I could not walk.

I don't know why you are on BB's but chat to the doc. See if the night bfore a ride would work.

And one warning- I had 3 months off exercise before the bypass- 6 weeks before I put ANY effort in on the bike and this was the first serious ride in 6 months. You may have to take care of the heart at present but don't forget the rest of the body. Keep it mobile and under effort to retain what strength you have in it. If you don't- I can assure you that pain hurts.