Why Blood Sugar Matters for Heart Health Even if You Don’t Have Diabetes

If your blood sugar is on the rise, it’s not just a diabetes risk. It may be a problem for your cardiovascular health, too.

Though the moderately elevated blood sugar levels of prediabetes were once thought to be relatively harmless, researchers now understand that prediabetes may present a significant heart health risk.

When we talk about heart disease risk factors, blood sugar often takes a back seat to cholesterol and blood pressure. However, there’s a profound and intimate connection between blood sugar levels and heart health.

Dace Trence, MD, professor-emeritus of medicine at the University of Washington in Seattle and president of the American Association of Clinical Endocrinology, says high blood sugar has two direct negative effects on the health of the cardiovascular system:

• Inflammation This immune system response involves the “increased production of components in the blood system that increase the risk of developing cardiovascular disease, such as cytokines or inflammatory modulators,” says Dr. Trence.
• Oxidative Stress This imbalance between harmful free radicals and protective antioxidants “leads to damage to cells,” she says.

Both of these factors increase the risk of developing cardiovascular diseases, according to Trence.

High blood sugar also triggers the excessive production of insulin, which enacts a harmful cycle known as insulin resistance. With insulin resistance, a defining feature of both type 2 diabetes and prediabetes, your body becomes less sensitive to the hormone insulin, which forces your pancreas to produce even more of it.

“Metabolic syndrome is a secondary effect of having long-term poor dietary habits and being sedentary,” says Neil Yager, DO, a cardiologist at Albany Medical Center in New York and president of the board of directors of his local American Heart Association chapter. If you have prediabetes or type 2 diabetes, you have at least one element of metabolic syndrome.

Most discussions of prediabetes focus on the risk of the condition progressing to type 2 diabetes. However, recent studies show that prediabetes raises a person’s risk of cardiovascular disease even if they don’t ultimately develop type 2 diabetes:

• A data set of 1.79 million hospitalizations revealed that people with prediabetes were 25 percent more likely to have a heart attack and twice as likely to need heart bypass surgery.

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• Data from hundreds of thousands of patients in the United Kingdom showed that men and women with prediabetes had a 30 to 50 percent greater risk of developing cardiovascular diseases than those without prediabetes.

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• A smaller study of patients in a single Michigan health center found that people with prediabetes had nearly twice the risk of serious cardiovascular events as people with normal blood sugar levels.

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“You can almost make an argument that the majority of people who have type 2 diabetes, especially longstanding diabetes, will develop coronary disease if they don’t implement lifestyle modifications and [take] certain medications,” says Dr. Yager.

Heart disease prevention is one of the most compelling reasons to try to stop or reverse the progression of prediabetes to type 2 diabetes.

“We also know that if high blood sugar is brought down, it can lead to longer survival after having had a heart attack,” says Trence.

Prediabetes remission involves getting blood sugar back down into the normal range: a fasting blood sugar below 100 mg/dL or an A1C below 5.7 percent.

The following lifestyle changes are the cornerstone of prediabetes treatment:

• Exercise Physical activity of any type improves blood sugar levels in people with prediabetes.

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• Build Muscle Strength-building exercise may be particularly beneficial for prediabetes remission, because more muscle mass removes more glucose from the bloodstream.

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• Avoid Processed Food and Added Sugar The Mediterranean diet, which prioritizes lots of fiber-rich fruits, vegetables, and whole grains, is considered the gold standard diet for prediabetes.

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   In support of this eating plan, Yager recommends shopping the perimeter of the grocery store, where most fresh foods are kept.
• Get Quality Sleep “Lack of sleep tends to increase insulin resistance,” says Trence. “It’s not just [about] the amount of sleep [you get], but also the quality of sleep. If you’re waking up frequently, that’s not going to be effective.”

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• Reduce Stress Chronic stress can negatively affect metabolic function, potentially leading to insulin resistance and the onset of type 2 diabetes.

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   If you’re feeling particularly bogged down, explore ways to reduce stress, including meditation and yoga practices, setting boundaries, and psychotherapy.
• Lose Weight Weight loss is one of the most powerful interventions for diabetes risk and heart health, especially when it’s combined with blood sugar reduction.

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There aren’t any medications approved to treat prediabetes, but it may be worth asking your healthcare provider if a drug can help reduce your risk of diabetes progression and heart disease.

If you have prediabetes and you’re concerned about your blood sugar levels, you may be wondering whether it’s worth the effort to measure your blood sugar between visits with your doctor.

You can now buy an over-the-counter continuous glucose monitor (CGM), a wearable device that tracks your blood sugar changes around the clock. However, experts say that tracking your blood sugar probably isn’t necessary for most people with prediabetes. Though using a CGM may help you learn which foods and habits are spiking your blood sugar the most, there isn’t much evidence that the technology has major benefits for diabetes prevention.

“The data isn’t really there yet, but maybe we’ll know more about it as time goes on,” says Yager. “For now, if you historically have had no issues, and you’re living a healthy lifestyle without any comorbidities, I’m not sure of the utility of checking [blood sugar] very frequently. I would follow your doctor’s directive on that.”

• Elevated blood sugar causes inflammation and oxidative stress, which can lead to stiffer blood vessels and thicker artery walls that increase your risk of heart attack and stroke.
• High blood sugar also triggers excessive insulin production, creating a cycle of insulin resistance that spikes traditional heart health risk factors, like blood pressure and cholesterol.
• Research shows that returning blood sugar to normal levels can cut the risk of cardiovascular hospitalization or early death in half, with heart health benefits lasting for decades even if remission is only temporary.
• Since there aren’t any medications specifically approved for prediabetes, experts recommend following a healthier diet, strength training regularly, getting quality sleep, and losing weight to improve metabolic function and protect the cardiovascular system.