Tuesday, April 03, 2018 Researchers Say Frequent TV-Watching Comes With VTE Risk That Can't Be Eliminated Through Physical Activity Dedicated binge-watchers take note: a new study has found that in addition to its link to other well-established negative health effects, regular long periods of television viewing can also increase risk for venous thromboembolism (VTE)—and it's a risk that isn't dramatically offset by increased levels of physical activity (PA). The study tracked the self-reported television viewing and PA habits of 15,792 participants aged 45-64 over a series of surveys that began in 1987-1989, with follow-ups every 3 years after that, through 2011. Participants were part of the Atherosclerosis Risk in Communities (ARIC) research initiative administered in Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and suburbs of Minneapolis. Researchers excluded participants who reported baseline VTE or anticoagulant use. Participants were asked to rate their television viewing habits during leisure time as "never," "seldom," "sometimes," "often," or "very often" at baseline, visit 3 (1993-1995), and visit 5 (2009-2011). Researchers also tracked estimates of physical activity using the Baecke physical activity questionnaire, which asks respondents to estimate the duration and intensity of PA during the previous year. Demographic variables and body mass index (BMI) also were recorded. Results were published in The Journal of Thrombosis and Thrombolysis (abstract only available for free). For purposes of the study, researchers divided PA responses into 3 levels based on American Heart Association recommendations: "recommended" (75 or more minutes per week of vigorous intensity PA or 150 or more minutes of a combination of moderate and vigorous intensity PA), "intermediate" (up to 74 minutes per week of vigorous intensity PA or up to 149 minutes per week of a combination of moderate and vigorous intensity PA), and "poor" (no reported vigorous or moderate PA). They also reduced television-viewing categories from 5 to 4 after finding that no participant reported "never" watching television. Here's what they found: Among all participants, 18.6% reported watching television "seldom," 46.8% reported watching "sometimes," 26.5% reported watching "often," and 8.1% reported watching "very often." Age, sex, and race-adjusted models showed a positive dose-response correlation between frequency of television viewing and VTE incidence (a total of 691 events during the study period), with participants who watched television very often having a 1.71 times higher risk of VTE than those reporting "seldom" watching television. The relationship of VTE risk to television viewing remained in place despite levels of PA. Participants who reported "recommended" levels of PA and watching television "very often" were found to have a 1.8 times greater risk of VTE than the seldom-watch group—a risk rating not much different from the 2.07 times increased risk associated with the group that reported watching television very often and having no PA. BMI did play a role. Obese individuals who reported watching television "very often" were found to have a 3.7 times higher risk of VTE than normal-weight individuals who reported watching television “seldom.” However, authors note that higher BMI did not explain the associations observed between television viewing and PA. The relationship between sedentary behavior and poorer health may be well-known, but authors of this study believe they've added a new dynamic—the inability of PA to counteract the risk for VTE caused by prolonged sitting. "These results suggest that sedentary behavior is not just the opposite issue from [PA]," authors write. While they acknowledge that individuals who engaged in more PA did lower their risk of VTE independent of television viewing frequency, the researchers also point out that "even individuals who met the…recommended level of [PA], when they viewed TV very often, had an increased risk of VTE compared with those who met the recommended level and seldom watched TV." The results echo findings in a study from 2017 that concluded that risk of a mobility disability increased relative to television-viewing time, regardless of hours spent in PA. [Editor's note: for more information on the role of the physical therapist in the treatment of individuals diagnosed with VTE, check out this clinical practice guideline available at PTNow.] Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.