Physical activity: measurement in mid-life women

Objectives. To review methods of assessing physical activity, and to compare two different questionnaires that were administered in the Melbourne Women's Midlife Health Project (MWMHP). Methods. Cross-sectional and subsequent longitudinal population-based study of Australian-born women who were aged 45-55 at baseline. Self-administered modified form of the Minnesota Leisure-Time Physical Activity questionnaire and interviewer-administered short physical activity question. Results. Two hundred and ninety-two women completed the Minnesota Leisure-Time Physical Activity questionnaire at both cross-sectional and 3rd year of follow-up (L3) and there was no difference in the total mean time spent exercising at both phases [5.9 (SD, 5.7) and 5.8 (SD, 5.0) hours per week, respectively]. The responses to the two questionnaires were significantly associated (beta = -0.89, SE 0.17, p <0.0005). Using the Minnesota Leisure-Time Physical Activity questionnaire between the cross-sectional and L3 phases, 10% of the women increased the time they spent exercising by 5 h per week and 10% decreased it by the same amount. Using the short exercise question, 12% of women decreased their participation by two or more sessions per week and 14% increased their participation by this amount between the cross-sectional and L3 phases. Conclusion. In this cohort of mid-life women the short exercise question was comparable in terms of measuring participation and change in physical activity with the more complex Minnesota Leisure-Time Physical Activity questionnaire.