Decline in Fitness Accelerates After Age 45
Men in Particular See Dip in Fitness Levels, but Exercise and Healthy Weight Can Help
Oct. 26, 2009 -- Fitness levels decline with age and accelerate after age 45
in men and women, a new study says. But staying at a healthy weight and
engaging in regular physical activity can help.
“The U.S. population is aging and is becoming more obese and sedentary,”
Andrew Jackson, PED, from the University of Houston and colleagues write in the
Oct. 26 issue of Archives of Internal Medicine. “It is well
documented that the cardiorespiratory fitness of men and women declines with
age and that body composition and habitual physical activity are related to
They add that low fitness levels increase the risk of diseases and interfere
with the ability of older adults to function independently.
The study included data on 3,429 women and 16,889 men aged 20 to 96 who
participated in the Aerobics Center Longitudinal Study between 1974 and 2006.
Most participants were white, well educated, and middle- to upper-socioeconomic
class with access to health care.
Participants completed between two and 33 health examinations and had
treadmill exercise tests to assess cardiorespiratory fitness.
Although fitness levels declined over time, cardiorespiratory fitness
declined more rapidly after age 45, and the decline was greater for men than
for women, the researchers say.
In addition, the results also “showed that being active, keeping a normal
BMI, and not smoking were associated with substantially higher levels of
cardiorespiratory fitness during the adult life span studied,” the researchers
say. “Being inactive and having a high body mass index were associated with a
lower age at which an individual could be expected to reach threshold
cardiorespiratory fitness levels associated with substantially higher health
Body mass index is a widely used calculation based on a person’s height and
weight. A person with a BMI of 25 to 29.9 is considered overweight, and a BMI
of 30 and higher is considered obese.
Because increasing rates of obesity and low levels of physical activity have
been observed in the general population, the researchers say their findings
suggest that more men and women will reach at a younger age the fitness level
designated by the Social Security Administration as representing
“These data indicate the need for physicians to recommend to their patients
the necessity to maintain their weight, engage in regular aerobic exercise, and
abstain from smoking,” the researchers say.
“The finding that BMI and a habitual level of physical activity are
important determinants of (cardiorespiratory fitness) raises a lifestyle
concern for the older adult population,” the researchers write.