Time USA - 18.11.2019

13

TheBrief Exercise

One 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 avoid

Running can help you

live longer. And more

isn’t always better

By Mandy Oaklander

having 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 years

23%

The risk reduction in

cancer deaths in the

same groups

46%

Share of Americans

who don’t meet the

minimum aerobic

physical activity

guidelines