A new study published in BMC Medicine has shown that reducing TV time to less than one hour per day may prevent 11% of cases of coronary heart disease.
Leisure activities involving screens, including TV viewing and computer time, are known to increase the risk of coronary heart disease. However, is it unclear whether and how genetic susceptibility may impact this correlation. To examine the connection between genetic susceptibility, screen time, and coronary heart disease, researchers used data from over 370,000 people in the UK biobank. They used this data to examine the participants’ genetic susceptibility to coronary heart disease, and TV viewing time and computer use were assessed through questionnaires.
The results of this study indicated that there was no significant interplay between genetic susceptibility to heart disease and time spent viewing TV; less time spent watching TV correlated to a lower risk of coronary heart disease regardless of the genetics of the participant. However, given the association between TV viewing and coronary heart disease, about 11% of cases could have been prevented if participants limited their TV viewing time to less than one hour per day.
TV viewing and computer time are associated with increased risk of heart disease largely because they increase sedentary behavior. Regular exercise is one of the best ways to prevent heart disease, and using leisure time to watch screens rather than stay physically active can lead to deteriorating heart health. In the study, people who watched 4 or more hours per day of TV were at the greatest risk of developing coronary heart disease; risk decreased at 2–3 hours per day and was lowest at less than one hour per day. This study provides an important reminder that exercise is essential for heart health regardless of genetic risk.