For people living with diabetes, seeing their blood sugar levels within the target range can feel reassuring. But is controlled blood sugar enough to keep the heart safe? Not necessarily.

Diabetes and heart health are closely connected. Even when blood glucose appears well controlled, a person may continue to have other cardiovascular risk factors such as high blood pressure, unhealthy cholesterol levels, obesity, smoking, physical inactivity or a long history of diabetes. These factors can contribute to the development of plaque inside the arteries and increase the risk of heart attack.

According to the U.S. Centers for Disease Control and Prevention (CDC), people with diabetes are about twice as likely to have heart disease or stroke compared with people without diabetes. The risk also tends to increase with the duration of diabetes.

Why can heart attack risk remain even when diabetes is controlled?

Blood sugar is only one part of cardiovascular health. Diabetes affects the body in several ways, and prolonged exposure to elevated blood glucose over the years can contribute to blood-vessel damage. At the same time, diabetes is often associated with high blood pressure, abnormal cholesterol and triglyceride levels, excess weight and insulin resistance.

Therefore, a person may have a satisfactory HbA1c reading but still have significant cardiovascular risk.

The arteries supplying blood to the heart can gradually develop a buildup of cholesterol and other substances called plaque. This process, known as atherosclerosis, can narrow the arteries and restrict blood flow. If a plaque ruptures and a blood clot forms, the artery can become blocked, resulting in a heart attack.

This is why diabetes management should not be viewed simply as a matter of keeping blood sugar numbers under control.

Cholesterol can be a hidden risk

One of the most important factors to watch is cholesterol, particularly LDL or "bad" cholesterol. Diabetes can be associated with an unfavorable lipid profile, including higher triglycerides, lower HDL or "good" cholesterol, and higher LDL levels. Such changes can contribute to plaque formation in the arteries.

Importantly, high cholesterol usually does not produce obvious symptoms. A person can feel perfectly healthy while plaque is gradually accumulating in the arteries.

For people with diabetes, therefore, periodic lipid testing and appropriate management of cholesterol are important components of cardiovascular risk reduction.

High blood pressure adds to the danger

Another major factor is hypertension. High blood pressure puts additional force on artery walls and can damage them over time. When diabetes and high blood pressure occur together, the cardiovascular risk can become significantly greater.

Blood pressure should therefore be monitored regularly, and the target should be individualized by the treating doctor depending on age, overall health, kidney function and cardiovascular risk.

Controlling blood pressure is not just about preventing a high reading on the machine; it is about reducing the long-term stress placed on the heart and blood vessels.

Smoking can further increase cardiovascular risk

Smoking is particularly dangerous for people with diabetes. Tobacco smoke damages blood vessels, promotes inflammation and contributes to the development of atherosclerosis. Nicotine can also raise blood pressure and make blood sugar management more difficult.

The CDC notes that smoking can worsen diabetes-related complications, including cardiovascular disease.

For a person with diabetes, quitting smoking can therefore be one of the most important steps towards protecting the heart.

Weight, diet and physical activity matter too

A healthy HbA1c should not become a reason to ignore lifestyle habits.

Excess body weight, especially when associated with abdominal fat, can contribute to insulin resistance, high blood pressure and abnormal cholesterol levels. Similarly, a sedentary lifestyle can increase cardiovascular risk.

Regular physical activity can improve insulin sensitivity, support weight management and help improve blood pressure and cholesterol. The CDC recommends regular moderate-intensity physical activity as part of heart-disease prevention.

Diet also plays an important role. A heart-friendly eating pattern should emphasize vegetables, fruits, whole grains, adequate protein and healthier sources of fat while limiting highly processed foods, excess salt, saturated fats and trans fats.

Diabetes duration also matters

Another factor that is sometimes overlooked is how long a person has had diabetes.

Even if blood sugar is currently well controlled, someone who has lived with diabetes for many years may have accumulated cardiovascular risk over time. This is one reason why cardiovascular assessment should remain a part of long-term diabetes care.

The goal should not be to wait until symptoms appear. Instead, risk factors should be identified and addressed early.

Does every person with controlled diabetes need heart tests?

Not necessarily.

People sometimes assume that having diabetes automatically means they need repeated ECGs, stress tests or scans even when they have no symptoms. However, current American Diabetes Association guidance does not recommend routine screening for coronary artery disease in asymptomatic people simply because they have diabetes, provided cardiovascular risk factors are being appropriately treated. Further evaluation may be considered when there are symptoms, signs of cardiovascular disease or other concerning findings.

This means cardiovascular care should be individualized rather than based solely on a diabetes diagnosis.

What should people with diabetes monitor?

Instead of focusing only on blood sugar, patients should take a broader approach to their cardiovascular health.

The important parameters include:

● HbA1c and blood glucose: To assess long-term and day-to-day glucose control.

● Blood pressure: To identify and manage hypertension.

● Lipid profile: Particularly LDL cholesterol and triglycerides.

● Body weight and waist circumference: To assess excess weight and metabolic risk.

● Kidney health: Diabetes-related kidney disease can further increase cardiovascular risk.

● Smoking status: Avoid tobacco in all forms.

● Physical activity: Maintain regular exercise according to individual health status.

● Diet: Follow a balanced, heart-friendly eating pattern.

● Family history: Inform the doctor about premature heart disease in close relatives.

The CDC describes this broader approach as managing the diabetes "ABCs"—A1C, blood pressure, cholesterol and smoking cessation—to help reduce the risk of heart attack, stroke and other complications.

Modern diabetes treatment is also looking beyond blood sugar

Diabetes treatment has evolved considerably. For some people with type 2 diabetes who have established cardiovascular disease, chronic kidney disease or multiple cardiovascular risk factors, certain medicines may offer cardiovascular benefits in addition to lowering blood glucose.

The 2026 American Diabetes Association Standards of Care recommend considering SGLT2 inhibitors or GLP-1 receptor agonists with demonstrated cardiovascular benefits in appropriate people with type 2 diabetes and cardiovascular disease or elevated cardiovascular risk. Importantly, some of these cardiovascular benefits are not dependent solely on how much the medicine lowers HbA1c.

However, these medicines are not suitable for everyone. Treatment decisions should be made by a qualified healthcare professional after considering an individual's medical history, kidney function, cardiovascular status, other medications and overall risk profile.

Recognise heart attack symptoms

People with diabetes should also be aware that heart problems do not always present dramatically. Symptoms can include chest discomfort or pressure, shortness of breath, unusual fatigue, dizziness, nausea or discomfort in areas such as the back, neck or upper body.

If symptoms suggestive of a heart attack occur, medical attention should be sought immediately rather than waiting for them to disappear.

Controlled diabetes is an important achievement, but it is not the same as being completely protected from heart disease.

The heart needs a comprehensive prevention strategy. Keeping blood sugar within the recommended range should go hand in hand with controlling blood pressure and cholesterol, maintaining a healthy weight, staying physically active, eating a balanced diet and avoiding tobacco.

For someone with diabetes, the question should therefore not simply be, "Is my sugar controlled?" It should be, "Are all my cardiovascular risk factors under control?"

Taking this broader approach can help identify hidden risks early and support better long-term heart health. Regular consultations with a healthcare professional can help determine an individual's cardiovascular risk and decide which tests, lifestyle measures or treatments may be appropriate.