I am the same way. After years of saying "I feel like crap" for the first 20-30 minutes of a ride, I realized that it takes me this long to warm up. I am also 52, so it might be age related, but I think it's more of a function of the way my HR works. It's always high when I start a ride, but then settles into a rhythm that is normal. I stopped using my HR monitor because it was driving me crazy. I think we don't take enough time to actually warm up. I tend to go right out and ride, and where I live, this means hills. I notice that when I ride with my friend who is slower and I make myself ride at her pace, I feel fine. I don't have this issue at the gym either.So, my advice is to go slow for at least 20 minutes and ride every other day. Do weight training or other muscle related work on the other days, or aerobic stuff that isn't as strenuous as cycling. Make sure you are eating enough protein after a ride.

Robyn