In middle-aged guys, how high the bottom number of your blood pressure is doesn’t seem to matter much for early artery thickening over four years—especially once you account for the top number, which might be more important.

What we've found so far suggests that diastolic blood pressure may not be strongly linked to carotid artery thickening in middle-aged men when systolic blood pressure is taken into account. The evidence we've reviewed leans toward the idea that the top number in a blood pressure reading might matter more for early artery changes over time. Our analysis of the available research shows that, in middle-aged men, diastolic blood pressure—the lower number in a blood pressure measurement—does not appear to have a meaningful association with the progression of carotid artery thickening over a four-year period once systolic blood pressure is adjusted for [1]. This means that even if the diastolic pressure is elevated, it doesn’t seem to add much additional risk for early arterial changes beyond what is already captured by the systolic pressure. The one assertion we analyzed, drawn from a body of 47.0 supporting studies with no refuting studies, points toward systolic blood pressure being a more relevant factor in this context [1]. We want to be clear that this is based on limited assertions—just one key claim so far—and while the supporting evidence is numerous, we are only seeing part of the picture. Our current analysis does not rule out any role for diastolic pressure, but it does suggest its influence may be minor compared to systolic pressure in this specific group. The takeaway: For middle-aged men, keeping an eye on the top number of your blood pressure might be more important when it comes to early signs of artery thickening. We’ll update our understanding as more evidence comes in.