Influence of time spent on TV viewing and vigorous intensity physical activity on cardiovascular biomarkers. The Inter 99 study.

INTRODUCTION: Sedentary behaviour, especially TV viewing, has been identified as a possible risk factor for cardiovascular disease, whereas physical activity seems to protect against major cardiovascular risk factors: obesity, dyslipidemia and hypertension. The aim of this study was to explore the association between both time spent on TV viewing and vigorous intensity physical activity in relation to body mass index, waist circumference, waist/hip ratio, serum lipids and blood pressure.

METHODS: A total of 1693 men and women, 33-64 years of age, from the 3-year follow-up of a population-based intervention study, The Inter 99 study, were included in this cross-sectional design. Information on TV viewing, physical activity and other lifestyle habits was obtained by self-report questionnaire. Associations between TV viewing/physical activity and biological cardiovascular risk factors were explored by multiple linear regression analyses.

RESULTS: Data from 835 (51%) men and 805 (49%) women were included. Mean age was 50.8 years (33.0-64.6). Men had a higher overall physical activity score than women (P<0.0001). TV viewing was significantly, positively associated with waist/hip ratio (P=0.005), body mass index (P=0.03), triglycerides (P=0.005), low density lipoprotein cholesterol (P=0.03), total cholesterol (P=0.01), systolic (P=0.05) and diastolic blood pressure (P=0.03), but not with waist circumference and high density lipoprotein cholesterol (HDL). Engaging in vigorous intensity physical activity was associated with higher HDL (P=0.0006) and lower waist circumference (P<0.0001).

CONCLUSION: TV viewing and physical activity should be regarded as separate types of behaviour that relate to different cardiovascular disease risk factors.