Ideal Caffeine Intake to Boost Muscle Endurance Athletes have
long known that caffeine boosts athletic performance by
increasing muscle endurance, but until now, knowing how much to
consume was largely a guessing game. Dr. Rob James, lead
researcher at Coventry University in central England, has found
the answer: Ingesting 6 milligrams of caffeine for every 2.2
pounds of body weight, just prior to exercise, increases muscle
output in the legs up to 6 percent. For a 154-pound person,
that's two cups of coffee. In researching mice and applying the
results to humans, James was able to identify what, as he puts
it, "could be the difference between an Olympic gold medal and
an also-ran." Ingesting any less than that, he says, had no
effect on performance.