Being out of shape
could be more harmful to health and longevity than most people expect,
according to a new, long-term study of middle-aged men. The study finds
that poor physical fitness may be second only to smoking as a risk
factor for premature death.
It is not news that
aerobic capacity can influence lifespan. Many past epidemiological
studies have found that people with low physical fitness tend to be at
high risk of premature death. Conversely, people with robust aerobic
capacity are likely to have long lives.
But most of those
studies followed people for about 10 to 20 years, which is a lengthy
period of time for science but nowhere near most of our actual
lifespans. Some of those studies also enrolled people who already were
elderly or infirm, making it difficult to extrapolate the findings to
younger, healthier people.
So for the new study, which was published this week in the European Journal of Preventive Cardiology,
researchers from the University of Gothenburg in Sweden and other
institutions turned to an impressively large and long-term database of
information about Swedish men.
The data set,
prosaically named the Study of Men Born in 1913, involved exactly that.
In 1963, almost 1,000 healthy 50-year-old men in Gothenburg who had been
born in 1913 agreed to be studied for the rest of their lives, in order
to help scientists better understand lifetime risks for disease,
especially heart disease.
The men completed
baseline health testing in 1963, including measures of their blood
pressure, weight and cholesterol, and whether they exercised and smoked.
Four years later, when the volunteers were 54, some underwent more
extensive testing, including an exercise stress test designed to
precisely determine their maximum aerobic capacity, or VO2 max. Using
the results, the scientists developed a mathematical formula that
allowed them to estimate the aerobic capacity of the rest of the
participants.
Aerobic capacity is an
interesting measure for scientists to study, because it is affected by
both genetics and lifestyle. Some portion of our VO2 max is innate; we
inherit it from our parents. But much of our endurance capacity is
determined by our lifestyle. Being sedentary lowers VO2 max, as does
being overweight. Exercise raises it.
Among this group of
middle-aged men, aerobic capacities ranged from slight to impressively
high, and generally reflected the men’s self-reported exercise habits.
Men who said that they seldom worked out tended to have a low VO2 max.
(Because VO2 max is more objective than self-reports about exercise, the
researchers focused on it.)
To determine what
impact fitness might have on lifespan, the scientists grouped the men
into three categories: those with low, medium or high aerobic capacity
at age 54.
Then they followed the
men for almost 50 years. During that time, the surviving volunteers
completed follow-up health testing about once each decade. The
scientists also tracked deaths among the men, based on a national
registry.
Then they compared the
risk of relatively early death to a variety of health parameters,
particularly each man’s VO2 max, blood pressure, cholesterol profile and
history of smoking. (They did not include body weight as a separate
measure, because it was indirectly reflected by VO2 max.)
Not surprisingly, smoking had the greatest impact on lifespan. It substantially shortened lives.
But low aerobic
capacity wasn’t far behind. The men in the group with the lowest VO2 max
had a 21 percent higher risk of dying prematurely than those with
middling aerobic capacity, and about a 42 percent higher risk of early
death than the men who were the most fit.
Poor fitness turned
out to be unhealthier even than high blood pressure or poor cholesterol
profiles, the researchers found. Highly fit men with elevated blood
pressure or relatively unhealthy cholesterol profiles tended to live
longer than out-of-shape men with good blood pressure and cholesterol
levels.
Of course, this study
found links between poor fitness and shortened lifespans. It cannot
prove that one caused the other, or explain how VO2 max might affect
lifespan. However, the findings raise the possibility, as the scientists
speculate, that by strengthening the body, better fitness may lower the
risk of a variety of chronic diseases.
This study also
involved men — and Swedish men at that. So whether the findings are
applicable to other people, particularly women, is uncertain.
But “there is no
reason not to think” that the rest of us would also share any beneficial
associations between fitness and longevity, said Per Ladenvall, a
researcher at the Sahlgrenska Academy at the University of Gothenburg,
who led the study. Past studies involving women have found such links,
he said.
Encouragingly, if you
now are concerned about the state of your particular aerobic capacity,
you most likely can increase it just by getting up and moving. “Even
small amounts of physical activity,” Dr. Ladenvall said, “may have
positive effects on fitness.”
Source: http://well.blogs.nytimes.com/2016/07/27/being-unfit-may-be-almost-as-bad-for-you-as-smoking/?_r=0
