High blood sugar, or hyperglycemia, is a significant risk factor for stroke, increasing the likelihood of this serious medical event.
What Are Hyperglycemia and Stroke?
Hyperglycemia signifies elevated levels of glucose in the blood. This often arises when the body either produces insufficient insulin or cannot effectively use the insulin it makes, a common characteristic of diabetes. For individuals without a diabetes diagnosis, a fasting blood glucose level above 125 mg/dL or a level exceeding 180 mg/dL two hours after eating indicates hyperglycemia.
A stroke is a sudden medical event where blood flow to a specific part of the brain is disrupted, causing brain cells to die. There are two main types: ischemic and hemorrhagic. Ischemic strokes, accounting for approximately 87% of cases, happen when a blood clot blocks an artery supplying the brain. Hemorrhagic strokes occur when a blood vessel in the brain ruptures or leaks, leading to bleeding.
How High Blood Sugar Increases Stroke Risk
Prolonged high blood sugar levels can damage blood vessel walls throughout the body, including those supplying the brain. This damage contributes to a process called atherosclerosis, where fatty deposits, or plaque, build up inside the arteries, causing them to narrow and harden. As arteries become stiff and constricted, the flow of blood to the brain is reduced, making an ischemic stroke more likely.
Chronic hyperglycemia also promotes persistent, low-grade inflammation within the body. This inflammation further injures the delicate lining of blood vessels, known as the endothelium, and exacerbates the development of atherosclerotic plaque. This sustained inflammation contributes to the overall deterioration of blood vessel health, increasing susceptibility to blockages.
High blood sugar levels can also make the blood more prone to clotting. This increased tendency for clot formation means that blockages can occur more easily within the brain’s blood vessels or that clots formed elsewhere in the body can travel to the brain. Such clots can then obstruct blood flow, leading to an ischemic stroke.
The impact of high blood sugar on stroke risk can manifest through both long-term and immediate effects. Chronic exposure to elevated glucose levels accelerates the progression of atherosclerosis and other vascular complications over many years, significantly increasing an individual’s lifetime risk for stroke. This sustained damage makes blood vessels less flexible and responsive to the brain’s changing demands for blood flow. Even acute, sudden spikes in blood sugar, sometimes referred to as stress hyperglycemia, can worsen outcomes for individuals experiencing a stroke, whether or not they have a prior diagnosis of diabetes. These acute elevations are associated with larger areas of brain tissue damage, an increased risk of complications, and higher mortality rates following a stroke event.
Reducing Your Stroke Risk Through Blood Sugar Management
Managing blood sugar levels effectively is a practical strategy to reduce the risk of stroke. Lifestyle modifications play a significant role in this effort.
Consuming a balanced diet that limits processed sugars and emphasizes whole grains, fruits, and vegetables can help stabilize blood glucose. Regular physical activity, such as at least 150 minutes of moderate aerobic activity weekly, helps lower blood sugar, improve insulin sensitivity, and contributes to maintaining a healthy weight. Maintaining a body weight within a healthy range is also beneficial, as excess weight, particularly around the waist, can increase the risk for both diabetes and stroke. Avoiding smoking also substantially reduces stroke risk, as it damages blood vessels and negatively impacts overall cardiovascular health.
Medical management and consistent monitoring are also important for mitigating stroke risk. Regular check-ups with a healthcare provider allow for the assessment of blood sugar levels, blood pressure, and cholesterol, all of which influence stroke risk. Adhering to prescribed medications for diabetes, high blood pressure, or high cholesterol, as directed by a doctor, is important for maintaining health. Routine blood sugar monitoring, including A1C tests, helps individuals and their healthcare teams ensure that glucose levels remain within a target range, generally below 7.0% for many people with diabetes. Understanding one’s blood sugar readings and seeking medical advice for persistently high levels allows for timely adjustments to management plans, further protecting against stroke.