Measurement of Physical Activity Among Black and White Obese Women

Several recent self-reported surveys have suggested that African-American women may engage in less leisure-time physical activity (PA) than whites. Objective measurements of PA have not been performed, however. Therefore, the purpose of this study was to compare the components of energy expenditure, including PA, between black and white obese women. Using the doubly labeled water method, total daily energy expenditure (TDEE), basal metabolic rate (BMR), thermic effect of a meal (TEM), and PA were measured in 14 black and 15 white moderately obese women over 2 weeks. No statistically significant differences were seen between the 2 groups in BMR, TEM or TDEE. Mean PA was significantly (p = 0.05) lower among black women compared to whites when expressed as MJ. d-1 (3.49 vs. 4.30) or kJ.kg-1.d-1 (37.6 vs. 47.7). Our study supports the survey differences seen in PA among black and white women.