You know the person. You work with them, or you’re friends with them, or maybe you even that person. They are youngish. Fit-ish. Always tracking their steps, sleep, heart rate, and meditation streaks. But these trackers overlook one metric: blood pressure. Those two numbers measure how well your blood vessels handle the 2,000 gallons of blood your heart pumps around your body in a day. And young people’s vessels aren’t doing the job so well.

Blue Cross Blue Shield recently released data from the claims of 55 million people. From 2014 to 2017, the prevalence of high blood pressure in people ages 21 to 36 jumped 16%. So, what exactly do we mean by “high”? We mean blood pressure that measures above 130 systolic or 80 diastolic. And when that happens, your blood vessels stiffen up, forcing blood pressure even higher. ... And a higher risk for heart attack and stroke.

For the longest time, most young people didn’t have to worry about this. Youth has always been a relative Teflon coating. Blood-pressure issues were strictly for older people, and the idea that this protection might be eroding is forcing doctors to examine what’s really going on. Here’s what they’re finding:

Millennials carry more than $1 trillion in debt. A large chunk of that is due to student loans—Millennials owe more than four times what Gen Xers do. Add this to other issues (such as bad eating habits and being overweight) and it makes sense that Millennials reported the highest average stress level of any generation, at 5.7 out of 10. (Gen Xers came in at 5.1, Gen Zers at 5.3, and boomers at a relatively zen 4.1.)