"Olebiker" writes:

I have to wonder if my friends ride bikes because they are
intelligent, or if they remain intelligent because they ride bikes
and stay otherwise active. I am going to operate under the
assumption that riding keeps you young and interesting. That way I
can justify keeping up this hobby and postponing my dotage.

Well, I know stupid people who ride bikes, average people who ride
bikes and smart people who ride bikes. I seem to know a lot of the
latter, actually, but that may say more about how lucky I am in
finding friends than about bicycling.

There is a body of evidence suggesting that aerobic exercise is
actually good for the brain, promoting (for reasons no yet known) an
increase in capillaries and blood perfusion to the brain. Regular
exercise does seem to be protective of cognitive abilities in aging,
which also tends to be true of mental activitiy as well. People who
regularly do crossword puzzles, for example, appear less likely to
suffer deficits in language skills; indeed, in general the
longitudinal testing has suggested that as people age, they tend to
keep the skills they use and tend to lose the skills they don't.

There are many famous examples of people cycling well into their
golden years, including three over-70 men who finished the 1200 km
ride Paris-Brest-Paris in under 90 hours (Roger Baumann, Jean Toulis,
and arrgh, forget the third- all of them have completed 10 PBPs).
Paul de Vivie (a.k.a. Velocio) rode well into his later years, doing
epic rides across France, the Alps, etc. He did complain of a loss of
abilities in later years, though, and decided he could no longer ride
more than 40 hours at a time. Dr. James-Edward Ruffier, who would
probably be called an exercise physiologist nowadays, lived to be 99
and cycled strenuously (on a fixed gear) into his 80s. He wrote a
number of books and developed an exercise method focused on developing
fexible strength, combining stretching and resistance training. Ed
Delano rode across the US at age 72 or something like that.

Age may take away some of your speed, but it shouldn't take away any
of your fun! I think the key to successful aging is to avoid acting
old.