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TheBrief ExerciseOne majOr reasOn americans dOn’t get
enough exercise is they feel they don’t have
enough time. It can be difficult to squeeze in
the 75 minutes of vigorous aerobic exercise per
week that federal guidelines
recommend; only about half of
Americans do, according to the
most recent numbers from the
Centers for Disease Control and
Prevention. But new research
suggests people may be able to
get life-lengthening benefits by
running for far less time.
In a new analysis of
14 studies, researchers tracked
deaths among more than
232,000 people from the U.S.,
Denmark, the U.K. and China
over at least five years, and
compared the findings with
people’s self-reports about
how much they ran. People
who said they ran any amount
were less likely to die during
the follow-up than those who
didn’t run at all. Runners were
27% less likely to die for any
reason, compared with non-
runners, and had a 30% and 23% lower risk of
dying from cardiovascular disease and cancer,
respectively. This was true even for those who
didn’t log a great deal of time. The analysis
grouped people into clusters, with 50 minutes or
less per week representing the group that ran the
least—but still ran.
“Regardless of how much you run, you can
expect such benefits,” says Zeljko Pedisic,
associate professor at the Institute for Health and
Sport at Victoria University in Australia, and one
of the authors of the new analysis published in the
British Journal of Sports Medicine.The analysis is The laTesT to illustrate the
benefits of running on the human body. “It’s
what we evolved to do,” says Daniel Lieberman,
a professor of human evolutionary biology at
Harvard University (who was not involved in
the new research). People may no longer chase
down prey for their next meal, but running is still
helping us survive: as leisure-time exercise, it
keeps us healthy. “One of the best ways to avoidRunning can help youlive longer. And more
isn’t always better
By Mandy Oaklanderhaving to see a doctor,” Lieberman says, “is to stay
physically active.”
The physical demands of running “affect just
about every system of the body” in a beneficial way,
Lieberman says. Take the cardiovascular system.
Running forces it to adapt by “generating more
capacity,” he says. “You grow more capillaries and
small arteries, and that helps lower your blood
pressure.” (High blood pressure is a major cause
of health problems and death.) Running is good at
guarding against cancer partly because it uses up
blood sugar, starving the cancer
cells that rely on it for fuel. And
it protects you in other ways
not necessarily measured in the
latest research: by decreasing
inflammation, for example,
which is at the root of many
diseases, and stimulating
the production of a protein
that improves brain health,
Lieberman says. “Vigorous
physical activity has been shown
to be by far—with no close
second—the best way to prevent
Alzheimer’s,” he notes.
The good news for people
who want the maximum
longevity benefits—while
spending the least amount of
time slapping one foot in front of
the other—is that running more
than 50 minutes per week wasn’t
linked to additional protections
against dying. Neither were
how often people ran and the pace they kept. As
long as you’re running, more isn’t always better,
especially given that the risk of injury increases
with repetition.
But both Pedisic and Lieberman advise people
not to cling too tightly to that number. “We
found no significant trends, but it’s not evidence
of no trend,” Pedisic says. “To be able to infer
something like that, you would need the whole
population measured.” (Important, too, is that the
results showed a correlation, not causation.)
Of course, people run for life-giving reasons, not
just death-defying ones. “Mortality is an important
variable to think about, but there’s also illness, and
happiness, and vitality,” Lieberman says. “Some
people are running in order to stave off Alzheimer’s,
and other people to prevent heart disease, and other
people because it makes them feel better and others
for depression.” No piece of research—including
the latest—can define a truly optimal number after
which all health perks wane. But one finding is
clear: anything greater than zero m.p.h. is where
ASHLEY GILBERTSON—VII PHOTO you’ll reap the biggest benefits. □
30 %
The risk reduction
in dying from
cardiovascular
disease among
runners, compared
with nonrunners,
over several years23 %
The risk reduction in
cancer deaths in the
same groups46 %
Share of Americans
who don’t meet the
minimum aerobic
physical activity
guidelines