older-adult client’s fitness level may be more important than his or her level
of body fat, according to a study in the December 5 issue of The Journal of the American Medical
Association (2007; 298 (21), 2507–16). The study found that people
over age 60 who had higher levels of cardiorespiratory fitness lived longer
than unfit adults, independent of body fat.
Researchers examined the
associations between cardiorespiratory fitness, various clinical measures of
adiposity (body fat) and death in 2,603 men and women aged 60 or older (average
age, 64.4 years; 19.8% women). Participants were enrolled in the Aerobics
Center Longitudinal Study and had completed a baseline health examination
between 1979 and 2001. Researchers used a treadmill test to assess fitness;
adiposity was measured by body mass index (BMI), waist circumference and
percent body fat.
Participants who died (there
were 450 deaths during an average follow-up of 12 years) were older, had lower
fitness levels and had more cardiovascular risk factors than survivors.
However, there were no significant differences in body fat measurements.
Participants in the fitter groups were less likely to have cardiovascular risk
factors such as hypertension, diabetes or high cholesterol. Fit participants
had lower death rates than unfit participants within each stratum of adiposity,
except for two of the obesity groups. In most cases, death rates for fitter
subjects were less than half the rates for those who were unfit.
“We observed that fit
individuals who were obese (such as those with BMI of 30.0–34.9, abdominal
obesity or excessive percent body fat) had a lower risk of all-cause mortality
than did unfit, normal-weight or lean individuals,” the authors said in a press
release. “Our data therefore suggest that fitness levels in older individuals
influence the association of obesity to mortality. It may be possible to reduce
all-cause death rates among older adults, including those who are obese, by
promoting regular physical activity, such as brisk walking for 30 minutes or
more on most days of the week.”