We all know regular TV-watching is a risk factor for obesity and associated health problems. Also, recent studies shined a light on the role of sedentary jobs.

Less attention has been paid to the threat of the lengthy car commute. But a new study [PDF] from the Center for Disease Control, National Institutes of Health and American Cancer Society is confirming what many have long suspected: lengthy car commutes are terrible for your health.

A study of more than 4,000 residents of greater Dallas found that those who commute more than 15 miles by car get less exercise and have larger waistlines and poorer cardiovascular health. Those who commuted more than 20 miles were also at greater risk for high blood pressure.

The results were adjusted for age, gender, education, family circumstances and health history.

One rather obvious explanation noted by researchers is that long commutes replace time that could be dedicated to exercise. The study’s authors also noted that “participants with long commutes were more likely to live in suburban neighborhoods, which often possess built environment features that are associated with physical inactivity and sedentary behavior.”

In addition, high blood pressure may also be caused by the stress of commuting, or the social isolation it produces, researchers said.