Estimating physical activity energy expenditure, sedentary time, and physical activity intensity by self-report in adults.

BACKGROUND: Few questionnaires that assess usual physical activity have been reported to be valid for all different subdimensions of physical activity.
OBJECTIVE: The objective was to assess the validity and reliability of the Recent Physical Activity Questionnaire (RPAQ), which assesses usual physical activity (PA) in 4 domains (work, travel, recreation, and domestic life).
DESIGN: Total energy expenditure (TEE) was measured for 14 d by using the doubly labeled water technique combined with a measure of resting metabolic rate to yield PA energy expenditure (PAEE) in 25 men and 25 women. Simultaneously, intensity of activity was measured by using combined heart rate and movement sensing for 11 d. Repeatability of the RPAQ was assessed in an independent sample of 71 women and 60 men aged 31-57 y.
RESULTS: Estimated TEE and PAEE were significantly associated with criterion measures (TEE: r = 0.67; PAEE: r = 0.39) with mean (+/-SD) biases of -3452 +/- 2025 kJ/d and -13 +/- 24 kJ d(-1) kg(-1). The correlation between self-reported and measured time spent was significant for vigorous PA (r = 0.70) and marginally insignificant for sedentary time (r = 0.27, P = 0.06). The mean biases were relatively small for sedentary time and vigorous PA: 0.7 +/- 2.8 h/d and -12 +/- 24 min/d, respectively. The intraclass correlation coefficient for repeatability of total PAEE (kJ/d) was 0.76 (P < 0.0001).
CONCLUSION: The RPAQ is the first questionnaire with demonstrated validity for ranking individuals according to their time spent at vigorous-intensity activity and overall energy expenditure.