Comparison of heart rate and physical activity recall with doubly labeled water in obese women

Accurate methods of estimating total daily energy expenditure (TDEE) that are inexpensive and differentiate activities of varying intensities are needed in obesity research. We compared minute-by-minute heart rate (HR) monitoring and the 7-d physical activity recall (PAR) questionnaire with doubly labeled water (DLW) for the measurement of TDEE and physical activity in 14 obese women (45% ± 4% fat, mean ± SD) before and during 12 wk of weight reduction. TDEE was measured over 2 wk by DLW. HR monitoring was conducted for 3 d, with individual VO₂/HR calibrations applied to HR data above 3 METs. PAR revealed the amount of time spent in sleep, moderate, hard, and very hard activities during 1 wk, with time spent in light activities determined by difference. Mean TDEE values, expressed as the % difference from DLW, prior to weight loss were −5.2 ± 10.8% by HR and 3.4 ± 14.4 by PAR, and during the diet were +0.9 ± 14.1% by HR and +0.9 ± 14.7% by PAR. Individual variability was high for both HR (−24.0 to +25.6%) and PAR (−27.4 to +36.2%). Energy expended in physical activity prior to weight loss were 3.97 ± 1.23 MJ·d⁻¹ by DLW, 3.91 ± 0.90 by HR, and 4.79 ± 0.95 by PAR. During weight loss, physical activity values by DLW, HR, and PAR were 4.31 ± 1.18, 4.84 ± 2.22, and 4.64 ± 1.06 MJ·d⁻¹, respectively. In summary, HR and PAR accurately assessed TDEE and physical activity for the group, but individual variability was high.