h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

It takes courage to write about longevity, particularly if you
hope to say something that will still be valid 30 years from
now. Remember "Athlete's heart," which was a popular
concept 50 or 60 years ago? Presumably, too much exercise
was supposed to cause your heart to enlarge. Indeed, exercise
was thought to have an adverse effect on your longevity,
because some studies of Harvard alumni had found that the
ones who were athletes during their college years didn't
live as long as the ones who were not.

Or, let's go back 20 years, to the heyday of jogging and
oat bran. Jogging and running were supposed to be so
great that you could never damage your heart by running
too much (Okay, you could set yourself up for severe
arthritis in later life, but that's another story . We know better,
now. Elite athletes can, indeed, show signs of heart damage
from excessive exercise. We just don't know which athletes
will suffer harm, and which ones won't. As for oat bran, the
oatmeal purveyors have been remarkably silent these last
few years. Gosh, I hope Wilford ("It's the right thing to do")
Brimley didn't get sidelined by heart disease!

Nowadays, coldwater fish with large supplies of omega-3
fatty acids are the rage. Those eskimos who gorge on these
fish have very low rates of heart disease, so this must be due
to the fish, right? Well, maybe not. The human genome
project has given scientist some new tools for establishing
genetic casue and effect. New studies suggest that
eskimo genetics are probably responsible for the low heart
disease rates.

Okay, why don't we just find some very old people, and
ask them why they have lived so long? Well, you'll get some
conflicting results. Some will say that they have never gotten
any exercise. Some drank alcoholic beverages, and some didn't.
Some smoked, some didn't. A nonagenarian in the court of
Louis XIV attributed his long lifespan to a diet of champagne
and lettuce leaves. Or, you may encounter a good many oldsters
who lie about their age--if they can remember it at all. A study
of 30,000 or 40,000 nurses found that the thinnest ones blew
everybody else away in terms of longevity. Then another
study, this time with 10,000 doctors, found lower heart disease
mortality from eating nuts. Now, common sense tells you that
eating nuts every day is probably not going to help you stay
thinner than almost everybody else. A third study found greater
longevity (but also higher rates of obesity) among people
with deep religious faith. Take your pick. And come back in
2031 to see what the new longevity rules will be .