I started riding at 65. I was rabid about both speed & distance. From June-December I rode 4700 miles, including two days the temperature was 16°. In mid September, I rode two Centuries on consecutive weekends. Two different courses, two different bikes, 15.3 mph average on both. On some shorter rides I could average 17 MPH if I was working hard.

6 years later, and my average speed continues to drop. Hard effort 20 mile rides are now 14.8 at best. I'm analytical, so I ponder why?

• My weight is the same. No change in life style or location.
• I'm riding less. First year I averaged 670 miles per month, rode 6 days a week, and did 1 or 2 hard effort rides each week. and "longer rides" were 50-65 miles.
• I'm not doing "fitness rides" now, but last year I was doing hard intervals (4x8 minutes, 2-3 minutes easy to lower the HR). I'd get my AHR up to 150, which is high for me. These didn't seem to improve my speed in my other rides. (They were hard! I did them once a week for 2 months, I was disappointed!)
• Now I only ride 450-500 miles/month (last year I started making an effort to do other things).
• Medical stuff. Last year I got a new knee, the year before a new hip (accident), the year before breast cancer, and the year before that prostate cancer. I rode throughout the cancer treatments, but lost 2-3 months for each joint.

Reasons I've slowed down speculation:

• Aging - is that the main culprit?
• Medical problems? I don't think the new hip or knee slows me down. I don't see how cancer treatment would have an impact after two years.
• Less riding? Would that really have that large an impact?
  • Decreasing my mileage per month?
  • Riding less long rides (I only do one 45-50 mile ride every week or two)?
• Defective Garmin? Hey, I think this must be the issue...

I pursued this subject once before on BF, So I dug it up and found it is more useful than I remembered. Post 39 is the pith of my analysis based on champion Ironman athletes. Cycling speed dropped by 7.7% for age group 65-69 compared to 60-64 - 16.3 MPH dropped to 15.1.

What sayest thou? Are there any studies showing the impact of aging beyond age 65? Do you have any comments?

PS - I know this is stupid! No fat person should be doing this sort of analysis. And for a brief period 3 years ago, I had lost 40#* and averaged 17 MPH on a 51 mile ride (44' ascent/mile). I remain determined to lose weight (I see a nutritionist Monday) but the weight is constant in the analysis above. Sadly the 40# loss was short lived.

*Breast cancer ended the weight loss.