What causes high blood pressure?

Introduction

High blood pressure—also called hypertension—is a common health issue affecting millions of people worldwide. It means the force of blood pushing against your artery walls is consistently too high. Over time, uncontrolled high blood pressure strains your heart, blood vessels and organs, increasing the risk of heart attack, stroke and kidney problems. Understanding what causes high blood pressure can help you take steps to prevent or manage it effectively.

How Blood Pressure Works

Blood pressure readings have two numbers:

• Systolic pressure (top number): the force when your heart beats.
• Diastolic pressure (bottom number): the force when your heart rests between beats.

A normal reading is around 120/80 mm Hg. Readings consistently above 130/80 mm Hg typically indicate hypertension. Blood pressure can rise temporarily during exercise or stress, but sustained elevations are what define high blood pressure.

Primary (Essential) Hypertension

About 90–95% of high blood pressure cases are classified as primary or essential hypertension. This means there’s no single identifiable cause. Instead, it develops gradually due to a mix of genetic and lifestyle factors:

• Genetic predisposition
– Family history of hypertension increases your risk.
– Certain gene variations affect how your body regulates salt and water.

• Age
– Arteries naturally stiffen as you get older.
– Stiffer arteries require more force to pump blood.

• Excess weight and obesity
– More body tissue needs oxygen and nutrients.
– The heart works harder, raising blood pressure.

• High salt (sodium) intake
– Too much sodium holds extra fluid in your body.
– This extra fluid increases the volume your heart must pump.

• Sedentary lifestyle
– Lack of regular exercise weakens your heart.
– A weaker heart must pump harder to circulate blood.

• Unhealthy diet
– Diets high in processed foods, sugar and saturated fats can raise blood pressure.
– Insufficient fruits, vegetables and whole grains reduce the nutrients that help blood vessels relax.

• Stress and poor sleep
– Chronic stress can trigger hormonal changes that raise blood pressure.
– Sleep problems, including sleep apnea, interfere with healthy blood-pressure regulation.

• Alcohol and tobacco use
– Heavy drinking and smoking both contribute to persistent blood-pressure elevations.

Secondary Hypertension

In about 5–10% of people with high blood pressure, an underlying condition or medication causes the rise. This is called secondary hypertension. Common causes include:

• Kidney disease
– Damaged kidneys can’t filter fluid properly, leading to volume overload.
– Narrowing of the renal artery reduces blood flow, triggering pressure-raising hormones.

• Hormonal disorders
– Overactive thyroid or adrenal glands release too much hormone, affecting blood vessels and fluid balance.
– Cushing’s syndrome and pheochromocytoma are less common but significant causes.

• Sleep apnea
– Repeated breathing interruptions at night create fluctuations in oxygen flow and stress hormones, raising blood pressure.

• Certain medications
– Some pain relievers (NSAIDs), decongestants, oral contraceptives and steroids can elevate blood pressure.

• Pregnancy-related hypertension
– Preeclampsia causes a dangerous rise in blood pressure during pregnancy.

Portal Hypertension in Liver Cirrhosis

While most discussions of high blood pressure focus on the systemic circulation, another important type is portal hypertension—high pressure in the veins that carry blood from your digestive organs to your liver. Chronic liver damage (cirrhosis) can cause scarring that obstructs this blood flow. Key points:

• Causes of portal hypertension
– Scarring (fibrosis) from hepatitis, alcohol misuse or fatty liver disease narrows vessels in the liver.
– Increased resistance forces pressure to build up in the portal vein.

• Consequences
– Fluid accumulation in your abdomen (ascites).
– Enlarged veins (varices) in the esophagus and stomach that can bleed.

• Risk prediction
– Tools like transient elastography (liver stiffness measurement) help estimate which patients face higher risk of decompensation and complications (Kim SU et al., 2019).

Common Risk Factors at a Glance

• Age over 65
• Family history of hypertension
• Overweight or obesity
• High-sodium diet
• Sedentary behavior
• Excessive alcohol intake
• Smoking or tobacco use
• Chronic stress or poor sleep
• Underlying kidney or endocrine disorders

What You Can Do

You can take several practical steps to help prevent or manage high blood pressure:

1. Adopt a heart-healthy diet

   • Emphasize fruits, vegetables, whole grains, lean proteins and healthy fats.
   • Limit processed foods, sugary drinks and excess salt.

2. Exercise regularly

   • Aim for at least 150 minutes of moderate activity (brisk walking, cycling) each week.
   • Include strength training two days a week.

3. Maintain a healthy weight

   • Even modest weight loss can significantly lower blood pressure.

4. Reduce sodium and alcohol

   • Aim for less than 2,300 mg of sodium per day (ideally 1,500 mg).
   • Limit alcohol to one drink per day for women and two for men.

5. Manage stress and sleep

   • Practice relaxation techniques (deep breathing, meditation).
   • Aim for 7–8 hours of quality sleep nightly.

6. Monitor regularly

   • Check your blood pressure at home with a reliable monitor.
   • Track readings and share them with your doctor.

If you’re curious about your symptoms or concerned about your risk, consider doing a free, online symptom check for high blood pressure.

When to Seek Professional Help

High blood pressure often develops quietly, without noticeable symptoms. However, if you experience:

• Severe headaches
• Chest pain
• Shortness of breath
• Vision changes
• Unexplained fatigue

…seek medical advice promptly. Any life-threatening or serious concerns should be evaluated by a healthcare professional without delay.

Conclusion

High blood pressure has many causes—from lifestyle and genetics in essential hypertension to specific medical conditions in secondary forms, and even portal hypertension in liver cirrhosis. Understanding these underlying factors empowers you to make targeted lifestyle changes and seek timely medical care. Always discuss any concerns or treatment changes with your doctor to ensure safe and effective management.