If you’re worried about how quickly you appear to be aging, you may have a problem that has nothing to do with what you eat or how much you exercise: you’re just sitting way too much. Scientists have found in a new paper that a sedentary lifestyle can age cells by up to eight years, and in combination with having a poor diet and not exercising, sitting too much can result in a perfect storm of unhealthy behavior.

The findings were made by researchers at the University of California San diego School of Medicine. They found that elderly women with low levels of physical activity who sit at least 10 hours per day have cells that are biologically older by eight years, compared to those who didn’t sit that long, according to a statement from the university.

They examined 1,500 women between 64 and 95 years of age, and had them complete questionnaires and wear an accelerometer for seven straight days while awake and asleep. They found that women who carried out less than 40 minutes of moderate-to-vigorous activity every day and were sedentary for longer than 10 hours tended to have shorter telomeres, which are at the ends of DNA strands and protect chromosomes from deterioration.