OBJECTIVES: In health evaluations, physical activity (PA) and cardiorespiratory fitness (maximal oxygen uptake [VO2max]) are important variables. It is not always possible to assess both of them. If the association between self-reported PA and VO2max was strong, it would be possible to use the information on PA to make assumptions about VO2max and vice versa. However, little is known about this relation, in particular among women at high risk for cardiovascular disease. Our aim was to study the association between self-reported PA (Short QUestionnaire to ASses Health enhancing PA) and fitness (determined using the Siconolfi step test) among sedentary women in a multiethnic population.

STUDY DESIGN AND SETTING: Participants were sampled from an exercise program for sedentary women (The Netherlands, 2008-09). Linear regression was performed with VO2max (dependent variable) and self-reported PA (independent variable); covariates were age and body mass index.

RESULTS: One hundred ninety-seven women from different ethnic backgrounds were included. No significant association was found between VO2max and PA (R(2) = 0.60).

CONCLUSION: A poor association was found between self-reported PA and estimated VO2max. Hence, PA and VO2max represent two different aspects of health in sedentary women and cannot be used interchangeably. This should be taken into account when evaluating health promotion interventions or when making health risks statements in sedentary women in a multiethnic population.