Excessive screen time has long been associated with a range of health issues, from poor sleep and obesity to mental health struggles. Now, a new study reveals how television watching, a common leisure activity and a popular form of screen use, affects cardiovascular disease risk in young adults.

The study suggests that every additional hour spent watching TV could increase the risk of heart disease by 26% in young adults.

Earlier studies have examined how television viewing affects cardiovascular disease risk, but they mostly focused on middle-aged and older adults and had relatively short follow-up periods.

The latest research, however, is a large-scale study involving more than 4,000 young adults between the ages of 18 and 30. To estimate the long-term risks of television watching on heart attack, heart failure, and stroke, the researchers followed up with the participants for 30 years.

The results published in the Journal of General Internal Medicine suggest that those who spent more time watching TV in their early 20s had a higher risk of developing these cardiovascular issues later in life.

Every additional hour spent watching TV daily at age 23 raises the risk of developing coronary heart disease by 26% and cardiovascular disease events by 16%. And for each extra hour of daily TV viewing each year, the risk soars even higher: 55% for coronary heart disease, 58% for stroke, and 32% for cardiovascular disease.

As per the study findings, the young adulthood is "an important window for intervention in television viewing habits to prevent adverse cardiovascular outcomes."

"In this prospective cohort study, greater television viewing in young adulthood and annual increases in television viewing across midlife were associated with incident premature cardiovascular disease events, particularly coronary heart disease. Young adulthood as well as behaviors across midlife may be important periods to promote healthy television viewing behavior patterns," the researchers wrote.

"Our findings suggest that the amount of time young adults spend watching screens can significantly influence their risk of developing serious heart conditions later in life. More screen time can displace important activities like sleep and physical activity. This underscores the importance of promoting healthy screen habits early in life to prevent future heart disease and stroke," study lead author Dr. Jason Nagata said in a news release.