Weight-independent cardiovascular fitness and coronary risk factors
B. Gutin, S. Owens, F. Treiber, S. Islam, W. Karp and G. Slavens
Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Augusta, USA. bgutin@mail.mcg.edu
BACKGROUND: It is unclear whether cardiovascular fitness influences risk
factors for coronary artery disease and non-insulin-dependent diabetes
mellitus independently of level of body fat because fitness is often
measured in tasks that involve moving body weight (eg, running) and because
body weight and level of body fat are correlated. OBJECTIVE: To measure
fitness during a task in which body weight was controlled experimentally
(ie, supine cycling). DESIGN: Cross-sectional. PARTICIPANTS: Seventy-four
children, 7 to 13 years of age, recruited through school flyers and
newspaper advertisements, varying in level of body fat from 7% to 61%.
There were 31 boys and 43 girls; 35 were white and 39 were black. MAIN
INDEPENDENT VARIABLES: Cardiovascular fitness was expressed as submaximal
heart rate while cycling at a power output of 49 W, and level of body fat
was measured with dual x-ray absorptiometry. MAIN OUTCOME MEASURES: Blood
pressure and levels of triglycerides, total cholesterol, high-density
lipoprotein cholesterol, low-density lipoprotein cholesterol, insulin,
glucose, and glycohemoglobin. RESULTS: Controlling for age and sex, level
of body fat was significantly (P < .01) related to unfavorable levels of
systolic blood pressure (r = 0.32), triglycerides (r = 0.42), high-density
lipoprotein cholesterol (r = -0.31), insulin (r = 0.50), and total
cholesterol to high-density lipoprotein cholesterol ratio (r = 0.37);
submaximal heart rate was not significantly correlated with any of the
other variables. CONCLUSIONS: When cardiovascular fitness was measured in a
weight-independent task, it was not significantly related to level of body
fat or the major coronary artery disease and non-insulin-dependent diabetes
mellitus risk factors. In addition, we confirmed previous findings that
higher levels of body fat are associated with a very unfavorable risk
profile.
