Many people with type 2 diabetes are still told that to reduce their risk of heart disease and other complications, they should bring their blood sugar level down low—sometimes very low. Often, that means trying to get their HbA1c, a measure of long-term blood sugar levels, under 6.5. 

But in fact, for several years now diabetes experts have known that for most people that's not only unnecessary, but potentially harmful.

Here's what you should aim for instead.

The Real Target

Getting your blood sugar levels below 6.5 is hard work. It often requires not only a serious commitment to lifestyle changes, but also high doses of diabetes drugs, sometimes multiple medications.

But as far back as 2008, studies were showing that people who lowered their HbA1c levels to under 6.5 had a higher risk of death than those whose levels were between 7 and 8.

“We suspect that if people get their blood sugar levels too low, their body’s response is to pour out stress hormones such as adrenaline, which can be harmful if you already have or are at risk for developing heart disease,” says Adam Cifu, M.D., a professor of medicine at the University of Chicago and co-author of “Ending Medical Reversal."  

Why do some doctors still recommend the lower number? “Old habits are hard to break,” Cifu says. Moreover, some medical groups still give financial incentives to doctors whose patients reach the lower targets, he says.

All this doesn't mean that controlling and measuring blood sugar levels is unimportant, says Marvin M. Lipman, M.D., Consumer Reports' chief medical adviser and an endocrinologist. "But most people should aim for an HbA1c level between 7 and 8," he says.

And it's still extra important for people with diabetes to take steps to control other risk factors for heart disease by, for example, stopping smoking, controlling high blood pressure and cholesterol levels, and often taking daily, low-dose aspirin.