How Diabetes Affects the Heart—And How to Reduce Risk

July 20, 2022 2:39 PM EDT

If you’ve been diagnosed with diabetes, know that you’ve got plenty of company. The American Diabetes Association (ADA) reports that in 2019, the most recent year for which data is available, 37.3 million adults in the U.S.—about 11.3% of the population—had the chronic condition, and that number continues to grow.

Type 1 diabetes develops when the body isn’t able to produce insulin, and Type 2 occurs when the body doesn’t use insulin correctly. Type 2 is the most common form of diabetes, and when it’s uncontrolled, a person’s blood sugar can jump to dangerous levels that require medical treatment.

Over time, elevated blood-sugar levels spell trouble for the entire body, says Dr. Joshua Joseph, an endocrinologist with the Ohio State University Wexner Medical Center in Columbus and an investigator with the ACCELERATE Research Group, which is working to prevent and treat diabetes and cardiovascular disease. “High levels of blood sugar damage the small and large vessels in the body,” including those around the heart, leading to heart disease, he says. Elevated glucose can also harm the nerves that control the heart.

Indeed, diabetes is correlated with a heightened risk of major adverse cardiac events, such as stroke, heart attack, and death. People with the condition are twice as likely to have a heart disease or stroke as those who don’t have diabetes, and it’s more likely to happen at a younger age. Plus, the longer people have diabetes, the more likely they are to develop heart disease, according to the National Institutes of Health. Here’s a look at what to know, plus expert tips on keeping your heart—and whole body—healthy.

The connection between diabetes and heart disease

People with Type 1 diabetes may have a lower risk of heart complications than those with Type 2. That’s because they’re less likely to be overweight or obese, which can increase the risk of heart problems. There’s also more research on Type 2, since it’s the most common form of the disease.

Despite some variations between Type 1 and Type 2 diabetes, in individuals with these conditions, cardiovascular disease is the No. 1 cause of death, says Dr. Robert Gabbay, chief scientist and medical officer of the ADA. It’s not entirely clear why and how diabetes and heart disease are connected, but there are likely several factors involved. These include:

Comorbidities

As Gabbay says, “People with diabetes are more likely to have other comorbidities that independently increase the risk of heart disease.” Conditions such as hypertension (high blood pressure), hyperlipidemia (high cholesterol), and obesity can increase the risk of heart disease. “When you start adding those together, the risk starts multiplying,” he says.

Systemic inflammation

Diabetes can create an inflammatory environment in the body, which Dr. Andrew Freeman, a cardiologist at National Jewish Health in Denver, calls this “a milieu” that can lead to other chronic problems. The high blood sugar that diabetes creates in the body can “lead to a variety of inflammatory states and microvascular disease, or small blood vessel disease,” Freeman explains. “The very same environment that helps create diabetes helps to create cardiovascular disease, and vice versa.” Systemic inflammation stemming from high blood sugar can lead to blood clots, stroke, and heart attack.

Insulin resistance

Obesity is related to insulin resistance, which means your muscles, liver, and fat cells don’t respond well to insulin and aren’t able to use the glucose in your blood to fuel their functions. Insulin resistance, sometimes called prediabetes, can develop into Type 2 diabetes. “Insulin resistance is associated with all sorts of other bad things, and one of these is inflammation,” Gabbay says.

The risk to the heart posed by diabetes is clear, Gabbay says, but the reverse is less clear—it’s not always the case that having heart disease puts a person at higher risk of developing diabetes. That said, “it’s not unusual. I’ve seen this many times that someone comes in with a heart attack, and they’re also diagnosed with having diabetes. They just never knew it.” In these instances, he says, diabetes likely contributed to the heart attack.

If you have diabetes, it’s important to recognize the symptoms of heart disease. According to the ADA, they include: chest pain; shortness of breath; fainting; a rapid or slow heartbeat; numbness in your legs; exhaustion; nausea and vomiting; and pain in one or both legs.

Depending on your symptoms, your doctor might order tests such as an electrocardiogram, which checks the heart’s electrical signals, or cardiac computerized tomography, which supplies 3-D images of your heart and blood vessels.

Reducing risk

Fortunately, there are many ways to reduce risk and limit progression of diabetes and heart disease, Gabbay says. The ADA is partnering with the American Heart Association to tackle the issue via a program called Know Diabetes by Heart. It aims to increase awareness of the connection between diabetes and heart disease and to provide patients with resources to keep themselves healthier.

It’s clear that treating diabetes appropriately can limit the risk of cardiovascular disease, Joseph says. This means “controlling the ABCs of diabetes.”

A stands for A1C, a measure of blood-glucose control over time. Keeping that level at your goal, which for most people is below 7%, means your diabetes is well managed and will do less damage to the body. This is usually accomplished through diet, exercise, and medication. If you’re not sure what your A1C goal should be, ask your doctor.

B stands for blood pressure. Controlling hypertension, often called the silent killer because it seldom produces symptoms, is a major component of managing heart disease. If your blood pressure is too high, it can cause a heart attack or stroke, as well as kidney damage and other health problems.

C stands for cholesterol, which is a type of fat found in the blood. Keeping blood vessels clear of the plaque that can build up when cholesterol levels rise helps prevent heart attack and stroke.

S stands for “stop smoking,” which doctors widely recommend. If you smoke, stop as soon as possible: it’s a major risk factor for diabetes and heart disease, as well as many other chronic conditions. Quitting smoking helps lower your risk for heart attack, stroke, and nerve, kidney, and eye disease.

Similarly, consuming too much alcohol can be a problem, as it can elevate blood pressure and lead to heart failure or stroke. One drink per day for women and up to two for men is typically considered “safe,” but keep in mind that a drink is a 12-oz. beer, 5 oz. of wine, or 1.5 oz. of 80-proof spirits.

Medications

A wide variety of medications are available to help control diabetes and slow its progression. They may also help manage your risk for heart disease. Insulin is the most common; it replaces the insulin your body can’t make or isn’t making enough of to control blood sugar. Metformin is another widely used medication that limits how much carbohydrate the intestines can absorb and boosts insulin sensitivity to help the body better manage blood-sugar levels. Other medications, like amylinomimetic drugs that are injected before meals, can slow the rate of digestion, lowering your blood-sugar levels.

Two new classes of medications show promise in treating glucose levels in people with Type 2 diabetes, Gabbay says. These medications—GLP-1 receptor agonists and SGLT-2 inhibitors—have been shown to have a significant impact on lowering the risk of heart disease and stroke. Both help lower glucose levels and may support weight loss and blood-pressure reduction.

Gabbay says these new medications “have been shown to reduce heart disease, cardiovascular mortality, and all sorts of cardiovascular-related issues, but they’re underutilized.” People with Type 2 diabetes and poor blood-glucose management would benefit the most, and of that group, only about 15% are using these medicines.

Managing diabetes can help prevent heart disease. However, for people who already have both conditions, treatments that address any damage that has occurred in the heart or blood vessels are important and should be delivered alongside blood-sugar management. Individuals with both conditions will likely also need to control blood pressure and cholesterol levels, which can be achieved through medications as well as diet and exercise.

Diet and exercise

Exercise is a key way to control Type 2 diabetes and support a healthy heart. For people with obesity, losing weight is typically advised, and exercise may help you achieve that.

Eating right is also important, a fact that was first emphasized in the 1940s. “Back then, there weren’t a lot of treatments for diabetes or heart disease,” Freeman says.

Today, we know more about how food contributes to the development of chronic disease or help improve overall health. Doctors often advise a plant-based approach that’s low in unhealthy fats.

One of the most widely recommended diets for overall health and wellness is the Mediterranean diet, which features mostly vegetables and fruits, whole grains, some fatty cold-water fish, and limited dairy and meat. The DASH diet, which stands for Dietary Approaches to Stop Hypertension, is also good for heart health. It’s rich in vegetables, fruits, and low-fat dairy, and limits sodium.

No matter which specific diet you adopt, Freeman says, there are five things he tells people who are trying to control their diabetes and, in turn, protect their hearts.

Exercise more. Aim to complete 30 minutes per day of moderate- or vigorous-intensity exercise, and make it a regular habit. “You want to be in a zone where it’s hard to talk while you’re exercising,” he says.

Eat plants. Following a predominantly low-fat, whole-food, plant-based diet—one that’s rich in fruits and vegetables without too many processed foods—is the way to go. Skip refined oils, processed meats, and fried foods, as these can contribute to higher cholesterol levels.

Get enough sleep. Many people with Type 2 diabetes have sleep problems because of unstable blood-sugar levels, according to the Sleep Foundation. If you can’t get enough sleep, talk to your doctor. “Seven hours a night of uninterrupted sleep is an incredibly powerful way to reduce cardiovascular disease,” Freeman says.

Stress less. Long-term stress can increase blood-sugar and blood-pressure levels: “High-stress environments raise blood pressure, cholesterol, and risk for cardiovascular events,” Freeman says. Try yoga, meditation, deep breathing, or spending time in nature to cope with your stress.

Love more. Connecting with others can be a powerful way to stay healthy. “A strong social network reduces the likelihood of a cardiovascular event,” Freeman says. A diabetes educator can also help you better understand the steps necessary to manage diabetes while protecting your heart.

People With Diabetes Are More Vulnerable to Heart Disease. How to Reduce the Risk