I will join the Medicare crowd at the end of July and near as I can tell my lungs have decided they are of now of no use while cycling!

Medicare/Weak Lungs???

So my question is - for those who were pretty fit and serious cyclists for a considerable time prior to Medicare - did your Medicare eligibility signal your lungs to give up the fight?

I've been a serious and fairly well conditioned road and mountain bike rider for the last 50 years (well only 30+ for mountain bikes). I used to avoid flat land riding because I really enjoyed long strenuous hills. I was a pretty good climber - not Cat III fast but few of my friends could climb with me. My two advantages were my high tolerance for pain and the ability to run my heart at 170+ for extended periods.

Even two years ago I was still going uphill pretty fast and having fun breathing hard and suffering.

Now I feel like I can't begin to suck in enough air to keep up with my heart which is still perfectly happy purring along at 165 forever (tread mill stress test). I know that research show that VO Max for well conditioned athletes declines about 5% - 8% per decade beginning around 40 years of age. But my problem is that it seems like the lungs began losing a great deal of capacity sometime around 63 or so.

During the last five years I've been riding 5000+ miles a year and during the last two years more like 8000 miles a year.

I've had annual physicals with all the required blood tests and there are no apparent medical problems.

My legs are still strong - I can climb in the same gears as I always used with no sense of leg weakness. I can also sit on a climb and spin like crazy which my preferred method due to my 7 prior knee surgeries. But, even while spinning, I run out of lungs way, way sooner than I remember - even when I was in my early 60s.

Questions:

Did my signing up for Medicare cause my lungs to give up on the bicycle thing?

Does the decline in aerobic capacity continue in such dramatic fashion?

Will the decline stabilize at some point?