Exercise - Symposium

Mette Aadahl (1,2) and Torben Jørgensen (1)
(1) Research Centre for Prevention and Health, DK-2600 Glostrup and (2) Department of Medical Orthopaedics and Rehabilitation, Rigshospitalet, DK-2100 Ø

A new physical activity scale for measuring physical activity
Introduction: Obtaining valid information on physical activity is essential when exploring the association between physical activity and health, but most existing methods have certain limitations. Many questionnaires focus on either work-related or leisure time physical activity. Other methods are very detailed, but complicated, expensive and time-consuming to administer. The aim of this study therefore was to develop and validate a physical activity scale for measuring physical activity in 24 hours of work, leisure time and sports.

Material and Methods: A random sample of 2.543 Danish men and women aged 20 to 60 were contacted by mail and asked to select frequent and relevant physical activities from a number of physical activities of known energy expenditure. The response rate was 61.7%. The selected physical activities were included in the physical activity scale, organised in 9 different MET (metabolic equivalent) levels, ranging from sleep/rest (0.9 METs) to high intensity physical activities (>6 METs). Face and content validity of the physical activity scale was examined through interview with 10 volunteer men and women. Criterion validity was assessed against accelerometry (CSA 7164) and physical activity diary in 40 volunteer men and women. The new questionnaire was applied in the three-year follow-up of an on-going population based intervention study: The Inter 99 study. The first 619 participants in the study have filled out the physical activity scale and the association between physical activity level and cholesterol, blood pressure, body mass index and waist circumference was assessed in liniar regression models.

Results: Validation of the physical activity scale showed that correlation between the activity scale and the diary was high (r=0.74, p=0.000), whereas correlation between the activity scale and the accelerometer measurement was poor (r=0.20, NS). In the Inter 99 population, physical activity level (measured by the new physical activity scale) was significantly positively associated with high density lipoprotein (HDL), but not with blood pressure. Furthermore a daily physical activity level below 45 METs was inversely associated with waist circumference and body mass index. The association was not significant for those with an activity level ≥45 METs.

Conclusion: The physical activity scale is a simple and valid alternative to measuring physical activity level by diary. It combines information on all types of physical activity, i.g. sports, leisure time and work-related physical activity in one measure. Further testing of validity and reliability should be carried out in order to make the activity scale a useful instrument for monitoring activity level in both research and clinical practice.