High blood pressure can build up silently, just as diabetes can, and the two diseases often develop in tandem. If you have diabetes, you’re twice as likely to have high blood pressure than the average person is, and about 60 percent of people with type 2 diabetes do. Controlling high blood pressure is critical if you have diabetes because the damage it causes contributes not only to atherosclerosis but also to kidney and eye disease. All told, it has a hand in 35 to 75 percent of all complications that go along with diabetes.
You need a certain amount of blood pressure (the force that blood exerts against artery walls) for good circulation. But too much gradually weakens the heart by making it work harder and damages the lining of blood-vessel walls, making it easier for atherosclerosis to set in. High blood pressure can also weaken arteries in the brain and cause them to balloon, a condition called an aneurysm. The bursting of an aneurysm is potentially fatal.
According to the ADA, you should strive to keep your blood pressure down to at least 130/80 mm Hg if you have diabetes — and lower than that is even better.