People with diabetes have a high risk of high blood pressure (hypertension), and vice versa. Having both conditions can make each condition worse. The cause-and-effect relationship is largely due to risk factors that diabetes and hypertension share, including obesity and an unhealthy diet.
The early diagnosis and treatment of diabetes may help reduce the risk of hypertension. It may also prevent potentially severe complications of high blood pressure, including heart disease, stroke, and kidney failure.
How Diabetes Causes High Blood Pressure
Studies suggest that diabetes—most specifically type 2 diabetes—doubles the risk of hypertension compared to people without diabetes. It does so directly and indirectly in several key ways:
- Shared risk factors: Type 2 diabetes and high blood pressure are influenced by many of the same risk factors, including obesity, an inactive lifestyle, an unhealthy diet, and excessive belly fat.
- Diabetic kidney disease: Diabetes can damage the kidneys, causing the blood pressure to rise as the body retains excessive sodium and water. It can also increase due to renal artery stenosis, a condition in which the blood vessels supplying the kidneys start to narrow.
- Vascular damage: Persistently high blood sugar, a characteristic of type 2 diabetes, can also damage blood vessels, causing an increase in blood pressure as the vessels narrow and stiffen.
- Insulin resistance: Type 2 diabetes is characterized by insulin resistance, in which the body is less responsive to the hormone insulin that regulates blood sugar. Insulin resistance, in turn, disrupts the sympathetic nervous system, which regulates blood pressure and sodium excretion.
How High Blood Pressure Causes Diabetes
While diabetes can lead to high blood pressure, hypertension can also contribute to type 2 diabetes in several indirect ways.
Among them, high blood pressure can cause changes in blood vessels that reduce the delivery of insulin and glucose to cells. This can lead to insulin resistance and diabetes as the body becomes less responsive to persistently high insulin levels. The pancreas, the organ that makes insulin, may also release less insulin over time as it becomes less able to keep up with persistently high glucose levels.
Hypertension and diabetes are also associated with oxidative stress (the imbalance of beneficial antioxidants and harmful molecules called free radicals in the body). As such, oxidative stress caused by hypertension can lead to the worsening of type 2 diabetes, and vice versa.
Risks and Long-Term Complications
Diabetes and hypertension are both associated with the overactivation of the renin-angiotensin-aldosterone system (RAAS). This is a coordinated system of hormones and enzymes that keep your blood pressure stable by controlling the amount of fluid in your blood vessels.
The overactivation of theRAAS is linked to type 2 diabetes and high blood pressure and also to potentially serious complications of type 2 diabetes and high blood pressure, including:
- Eye diseases: Alone or together, diabetes and high blood pressure can increase the risk of glaucoma by around 20% compared to people without either disease. Poorly controlled hypertension also doubles the risk of diabetic retinopathy, a serious eye complication of type 2 diabetes.
- Heart disease: Together, type 2 diabetes and hypertension increase the risk of cardiovascular disease by twofold to fourfold compared to adults without type 2 diabetes or hypertension. This includes an increased risk of heart attack, coronary artery disease (CAD), and heart failure.
- Stroke: People with diabetes have double the risk of strokecompared to people without diabetes. The risk is even greater in those with diabetes and hypertension, who are two to six times more likely to experience an ischemic stroke (blockage of blood flow in the brain).
- Chronic kidney disease: Diabetes and hypertension are both considered causes of chronic kidney disease (CKD).
How to Know If You Have Hypertension
Hypertension affects nearly half of all adults in the United States and is often called a "silent killer" because it rarely causes symptoms.
Even so, it can easily be detected with an inflatable device known as a sphygmomanometer (blood pressure cuff) that measures both your systolic blood pressure (the first or upper number measuring pressure on the artery walls when your heart contracts) and lower diastolic blood pressure (the second of bottom number measuring when your heart is at rest).
According to the American Heart Association (AHA), you have hypertension if your blood pressure is 130/80 millimeters of mercury (mm Hg) or higher. While the American Diabetes Association (ADA) previously set the baseline at 140/90 mm Hg for people with diabetes, it revised its definitions in 2023 to align with those of the AHA.
How to Manage Blood Pressure in Diabetes
No less than 70% of adults living with diabetes have high blood pressure, while roughly 50% of adults with hypertension have insulin resistance. The effective management of both conditions can prevent potentially severe complications like heart attacks or strokes.
Lifestyle Changes
Diabetes and hypertension share many risk factors and can benefit from modifications to your diet and lifestyle, including:
- Eating a balanced diet: This includes increasing your intake of fruits, vegetables, whole grains, and lean poultry or fish, and cutting back on saturated fat, refined carbohydrates, sodium, and fatty or processed meats.
- Exercising regularly: Get at least 150 minutes of moderate-intensity aerobic activity each week to include exercising on most days of the week. Moderate-intensity exercises are those in which you can talk but not sing, such as brisk walking, cycling, dancing, or playing doubles tennis.
- Maintaining a healthy weight: If you are overweight or have obesity, consider working with a personal trainer and/or nutritionist to achieve and maintain a body mass index (BMI) between 18.5 and 24.9.
- Quit smoking: Smoking causes the narrowing of blood vessels, which independently raises blood pressure. To improve your odds of quitting, ask your healthcare provider about smoking cessation aids, many of which are fully covered under most insurance plans, including under the Affordable Care Act.
Medications
If lifestyle modifications are not enough to bring your blood pressure under control, your healthcare provider may prescribe medications known as antihypertensives. These drugs, taken by mouth, can be used alone or in combination to help regulate blood pressure.
First-line options include:
- Thiazide diuretics (drugs that remove salt and water from the body and prevent reabsorption of sodium and water in the nephrons, which filter waste and fluids) like Clorpres (chlorthalidone)
- Calcium channel blockers (drugs that limit how the body uses calcium) like Norvasc (amlodipine)
- Angiotensin converting enzyme (ACE) inhibitors (drugs that block the production of a substance that narrows blood vessels and raises blood pressure) like Lotensin (benazepril)
- Angiotensin receptor blockers(ARBs) (drugs that widen blood vessels and lower blood pressure) like Cozaar (losartan)
For people with treatment-resistant hypertension, especially common in people with diabetes, a class of diuretics called mineralocorticoid receptor (MR) antagonists may help. These include drugs like spironolactone which may also reduce the risk of heart disease complications.
Monitoring
Due to high rates of hypertension in the United States, the U.S. Preventive Services Task Force (USPSTF) recommendsannual blood pressure screening for all adults 40 years and older, along with anyone at increased risk of hypertension (such as smokers or people with diabetes).
For people ages 18 to 39 without risk factors, blood pressure screening every three to five years is appropriate.
Another key to keeping diabetes and hypertension under control isto self-monitor with home devices. This includes standard or continuous glucose meters used to track blood sugar levels and at-home sphygmomanometers that help you monitor your blood pressure.
Experts recommend buying automatic, upper arm cuff-style monitors, which are more accurate than wrist or finger monitors. By keeping track of your readings, you can contact your healthcare provider if your treatments are not working or are causing abnormal drops in blood pressure.
Ways to Lower Your Risk
You can't always avoid diabetes or hypertension, given that genetics may predispose you to the diseases. With that said, both type 2 diabetes and hypertension are greatly influenced by modifiable risk factors that you can change.
Strategies to reduce risk for developing hypertension include:
- Reducing your salt intake: The AHA recommends no more than 2,300 milligrams (mg) of sodium per day, equal to 1 tablespoon of table salt. If you have trouble controlling your blood pressure, cut back to 1,000 to 1,500 mg daily.
- Finding salt substitutes: Use herbs, spices, and lemon juice to season your food rather than salt.
- Checking food labels: Choose foods with less than 400 mg of sodium per serving, and avoid processed or fast foods that are typically high in sodium.
- Trying the DASH diet: The DASH (Dietary Approaches to Stop Hypertension) diet is a flexible and balanced eating plan with a proven record of helping people lower their blood pressure.
- Limiting your alcohol use: Alcohol can increase your heart rate and blood pressure for up to 24 hours after consumption. Experts advise that men should have no more than two alcoholic drinks per day, and women should have no more than one alcoholic drink per day.
- Managing stress: Stress contributes directly to high blood pressure but can also contribute to diabetes by triggering behaviors like smoking and overeating. Routine exercise and improved sleep hygiene can reduce stress, along with mind-body therapies like yoga and meditation.
Summary
Diabetes and hypertension are strongly linked, often occurring together due to disease mechanisms and risk factors. Having both conditions can increase the risk of heart disease, stroke, kidney disease, and other complications. The effective management of both diabetes and high blood pressure is crucial to reducing these risks.
