Comparison of the college alumnus questionnaire physical activity index with objective monitoring

Abstract

Purpose

Two methods of measuring physical activity (PA) were compared over a consecutive 7-day period among 25 adults (12 men and 13 women).

Methods

Each day estimates of energy expended in light, moderate, vigorous, and total PA were derived from the simultaneous heart-rate motion sensor (HR+M) technique. At the end of the 7-day period participants completed the College Alumnus Questionnaire Physical Activity Index (CAQ-PAI) and results were compared with HR+M technique estimates.

Results

Correlations between the two methods in the four activity categories ranged from r = 0.20 to r = 0.47, with vigorous and total PA showing higher associations than light and moderate PA. Mean levels of PA (MET-min·wk⁻¹) obtained using the two methods were similar in the moderate and vigorous categories, but individual differences were large. Energy expended in light PA was significantly underestimated on the CAQ-PAI, resulting in lower total activity scores on this questionnaire as compared with the HR+M.

Conclusions

The CAQ-PAI accurately reflected mean moderate and vigorous activity in comparison with the HR+M technique. The results are consistent with other studies which have shown that physical activity questionnaires are better at assessing vigorous PA than ubiquitous light-moderate activities.

Introduction

Evidence is available to support the importance of regular physical activity (PA) to promote good health and prevent chronic disease, including coronary heart disease, hypertension, diabetes, and some cancers (1). One of the most widely used assessment techniques for estimating PA levels in epidemiological investigations is the questionnaire. The feasibility and practicality, in both time and cost, of questionnaires makes them the instrument of choice in large-scale studies examining the relationships between PA and selected health parameters (2). One commonly used questionnaire to estimate PA is the College Alumnus Questionnaire (CAQ) (3). The CAQ physical activity index (CAQ-PAI) is an overall measure of the kilocalories expended in leisure-time physical activity, and is computed from the sum of city blocks walked, flights of stairs climbed, and sports, recreation, and other physical activities. One of the main advantages of the CAQ-PAI is its ability to rank individuals according to physical activity level in large-scale population based studies. More specifically, this instrument has been used to examine associations between total PA and hypertension (4), cancer 5., 6., 7., coronary heart disease (8), stroke (9), mortality 10., 11., and longevity 10., 12.. In addition, the CAQ-PAI provides information on intensity allowing the effects of moderate vs. vigorous activity to be compared (13).

The limitations associated with recalled PA on questionnaires have been well documented 14., 15., 16. and include a low accuracy for recalling light to moderate activities. To date, the lack of a suitable criterion standard has been a methodological limitation to examine the accuracy of PA questionnaires during field-based PA investigations. Recently, research has demonstrated that the simultaneous heart rate-motion sensor (HR+M) technique is an accurate, objective method for quantifying energy expenditure (EE) during specified lifestyle tasks (17), and for quantifying minute-by-minute EE, total EE, and time spent in varying activity intensities during free-living activity (18). This technique utilizes individual calibration curves between HR and oxygen uptake (V̇O₂) developed in the laboratory for both arm and leg exercise. Then, in the field setting, motion sensors are used to discriminate between arm and leg movement, and HR is used to predict the V̇O₂ from the corresponding individualized regression equation. Although the accuracy of the CAQ-PAI has been reported previously (19), at this time, the CAQ-PAI has not been compared with an objective assessment criterion able to accurately discriminate between light, moderate, and vigorous intensity PA. Therefore, the primary purpose of this study was to compare respondent estimates of intensity-specific PA assessed by the CAQ-PAI to those measured by the HR+M technique over 7 days of regular daily activity. A secondary purpose was to compare the ability of the CAQ-PAI to estimate total PA levels in comparison with the HR+M technique over the same time period.