Last week my friend, Chris, was gasping for air as we stopped after a long climb. He is about fifteen years my junior and asked how much speed/endurance (not the words he used) drop-off I encountered as I aged. I thought about my race times and answered that not much changed. Now that I've had a chance to consider the question in totality, I need to expand on the answer. Chris rides a lot but doesn't race, yet.
I started racing Senior Games at 62 and was pleased that in the first four that year I didn't finish last. I was no where near first. I also started doing cycling vacations of various lengths several years prior to that, including riding coast-to-coast. There is nothing like 52 days (48 cycling, 5 rest) of 80 miles per day average to increase strength and stamina. But let's get back to the question at hand.
From 62 to 77 my racing times didn't drop off much. The reason for that is the amount of race training I did increased quite a bit. It also included a dramatic change in equipment. The new bikes/tires are 'way much faster than what I had been racing on. I spend a lot more time in the gym (3-5 days a week), beginning several years ago. Since Chris doesn't race, I started thinking about my routine rides. I've been taking the same road up to Walburg for twenty-five years. There is one particular short climb (maybe fifty yards) that I remember taking in the big ring without a problem. I haven't been able to do that in fifteen years. I can still make it up Courtyard and Jester without stopping, but I'm using bigger and bigger cogs to achieve that. So, a slightly different answer to the question: if you keep doing what you were doing, yes, you will get slower. You have to do more. It takes more reps (like twice to four times) to achieve the same strength. Pay lots more attention to your cardio-vascular system.
Here is what I suggest: a weekly hill ride and a weekly HR ride. The Wednesday ride out of Trek Research has a decent amount of climbing, but there are other challenges around Austin. There are several drills I do: 15 second accelerations followed by 45 seconds rest by ten times; rest five minutes and do it again and a third time. Increase that to 20/40 and 30/30 as you develop. Or, 3 sets 5 minutes each 60, 100, 80 rpm with five minutes between. Both of those can also be done on a trainer. Another HR drill is Jumps. Starting at 90 rpm, do a 15 second out of saddle acceleration. After 15 minute warm-up, do ten of these with 5 minutes between (actually, 4 minutes, 45 seconds to keep timing simple).
One more caveat: exercise is one of the easiest habits to break. CONSTANT VIGILENCE! As Professor Moody would say.
