Not only did I read OP but this whole thread. Why? I too am not what I used to be. Biking is a recent adventure for me. Having a heart attack at 48 made me realize is was not in the shape I thought I was. While not extremely over weight I was just not taking care of myself in any form, eating right, living right, resting right and certainly worrying too much. I picked up the bike to get back in shape. After two years of riding 20 miles most every evening after work, I still am not sure I could do a century. Heck I am not sure I can do half a century. But that is my goal this year. At least do 50 in one day. I am not sure if it is the heart drugs I am on or what but I feel really drained after my 20 in the evenings. Especially in the heat of summer. Oh to be able to ride 100 miles at 62. Heck I hope I live till 62. I will say this, I have no friends who are riders. All my friends are impressed I can do 20 miles every evening after work. I am thankful I can also.