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Int J Obes Relat Metab Disord. 1998 Mar;22(3):215-21.

Differences in resting metabolic rates of inactive obese African-American and Caucasian women.

Author information

1
Exercise Science Programs, The George Washington University Medical Center, Washington, DC 20052, USA.

Abstract

OBJECTIVE:

To compare resting metabolic rates (RMR) of African-American (n = 25) and Caucasian (n = 22) premenopausal (35+/-1 y, Mean +/- s.e.m.) women who are obese (95.2+/-2.9 kg, body mass index (BMI) = 34.7+/-0.9, % body fat = 45.2+/-0.9), inactive and free from metabolic disorders or medications that would affect heart rate or RMR.

MEASUREMENTS:

RMR and respiratory exchange ratio (RER) by indirect calorimetry, body composition by plethysmography, maximal aerobic capacity (VO2max) and girth measurements.

RESULTS:

Group mean comparisons were made with a Student's t-test or an ANCOVA, which controlled for individual differences in body weight and lean body mass (LBM). Significance was set at P < 0.05. Groups were not significantly different in age, height, weight, BMI, % body fat, fat mass, RER, VO2max, resting heart rate, maximal heart rate; or chest, waist, hip, arm, thigh or calf circumferences. After adjusting for body weight, RMR (I O2/min) for African-Americans (0.254+/-0.007) was significantly lower (9%) than for Caucasians (0.277+/-0.008). After RMR (I O2/min) was adjusted for LBM, an even larger difference (-12%) persisted for African-Americans (0.250+/-0.008) compared to Caucasians (0.281+/-0.008). Predicted RMR (kJ/d) for the African-Americans was the same as measured RMR, whereas Caucasian women expended about 13% more energy than predicted. When controlling for LBM, the partial correlation between VO2max and RMR was r=0.51 when VO2max was expressed as I/min, and r=0.56 when VO2max was expressed as ml O2/kg/min, both highly significant (P < 0.000).

CONCLUSION:

The lower prevalence of obesity in Caucasian women may be due in part to a higher RMR as well as an under estimation of RMR in weight control therapy. Fitness level (VO2max) as well as LBM are significant predictors of RMR for both races.

PMID:
9539188
[Indexed for MEDLINE]

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