Assessing Physical Activity in Older People: Findings from the Hertfordshire Cohort Study

Background: Physical activity (PA) is difficult to assess and few instruments are relevant to older people. We have developed a self-administered PA questionnaire (HPAQ) for the Hertfordshire Cohort Study; we report its feasibility and validity and describe PA participation in older people. Methods: 525 participants completed the HPAQ; 15 women also completed the EPAQ-2 for validation. Activity participa- tion was described using percentage participation, estimated energy expenditure and cluster analysis. Results: Most participants found the HPAQ simple to complete. Agreement between the HPAQ and EPAQ-2 was good. Activities with highest participation rates and energy expenditures were walking (99.6%, 149.8 MET.h/mth) for men and home activities (100%, 287.1 MET.h/mth) for women. Clustering identified three patterns of activity participation for men ("Keep Fit", "Indoors" & "Less active"), and two for women ("Keep Fit" & "Indoors"). Conclusions: The HPAQ is a feasible and valid PA questionnaire for older people. Clustering identified different patterns of PA participation.