Sitting in front of television for hours may elevate blood pressure
Watching television for hours is associated with higher systolic (SBP) and diastolic blood pressure (DBP) in both men and women at most ages, suggests a recent study. On the other hand, increased physical activity may lower DBP, and high physical activity in young men may compensate for prolonged television time in terms of DBP.
An association existed between high physical activity and lower DBP (p=0.001), but not SBP. Active middle-aged men vs inactive participants had lower DBP (–1.1 mm Hg; 95 percent CI, –1.7 to –0.4).
In both sexes and in most age groups, prolonged television time correlated with higher SBP (p<0.001) and DBP (p=0.011). Three hours rather 1 hour of watching television per day could elevate SBP in middle-aged women (SBP, 1.1 mm Hg; 0.7–1.4) and men (SBP, 1.2 mm Hg; 0.8–1.6).
Of note, only in young men could a high physical activity (level 4 instead of 1) offset a prolonged television time (3 hours/day) with regard to DBP.
The investigators sought to determine if an interaction existed between sitting time and leisure time physical activity on BP, and if there were age and sex differences in this matter. They performed linear regression analysis on cross-sectional data in more than 45,000 men and women from two Swedish cohort studies (EpiHealth and LifeGene). Self-reported leisure time physical activity was given in five levels, from low (level 1) to vigorous physical activity (level 5), and television time was used as a proxy measure of sitting time.