Objective To describe and compare physical activity levels, sedentary and moderate-to-vigorous physical activity (MVPA) behaviour in HSE2008 in a representative sample of the adult population, using both objective (accelerometry) and subjective (self-report via questionnaire) methods of measurement.

Design Nationally representative cross-sectional population data from Health Survey for England, 2008.

Setting Random sample of the general population living in private households in England.

Participants Subsample of 4507 adults aged 16+ were selected for accelerometry wear, of whom 2115 adults had valid accelerometry data wear (with at least 600 min per day).

Main Outcome Measure Prevalence of those adults who meet the current physical activity (PA) recommendations by accelerometry data. Mean sedentary (minutes) and MVPA minutes (accelerometry).

Results Based on accelerometry data, 6% of men and 4% of women met the Chief Medical Officer's current minimum recommendations for PA by achieving at least 30 min of moderate or vigorous activity on at least 5 days in the week of accelerometer wear. Men and women aged 16–34 were most likely to have met the recommendations (11% and 8%, respectively). In contrast, based on self-report measures, 39% of men and 29% of women were said to have met the PA recommendations. Only 10% of men and 8% of women whose self-reported activity level corresponded with meeting the recommendations also met the recommendations based on accelerometry. Overall, men had significantly longer periods of sedentary time per day than women (595 min and 584 min, respectively), (p=0.003). While men spent an average of 31 min in MVPA in total per day, and women an average of 24 min, most of this was sporadic activity. Those who were not overweight or obese spent few minutes on average in sedentary time (591 min for men and 577 min for women) than those who were obese (612 min for men and 585 for women). Similarly, adults not overweight or obese spent more MVPA minutes than those who were overweight or obese. This pattern was similar with each BMI category.

Conclusion Subjective self-reported method of assessing physical activity resulted in higher levels of activity than objective accelerometry data. Despite this, the results from objective accelerometer data corroborate self-report findings across age and sex. Objective measures provide more accurate data and should be used where available. Comparison between objective and subjective methods indicates that people over estimate their actual physical activity levels.