When your heart beats, it contracts and pushes blood through your arteries. The pressure created during that contraction is called systolic pressure, and it represents the higher of the two numbers in a blood pressure reading. Between beats, the heart relaxes and pressure drops. That resting pressure is called diastolic pressure, and it is the lower number in the reading.

Blood pressure is measured in units called millimeters of mercury, abbreviated as mm Hg. A reading is expressed as two numbers written one over the other, such as 120/80 mm Hg. The top number is systolic; the bottom number is diastolic.

Your blood pressure naturally goes up and down throughout the day. It rises when you exercise, feel stressed, or drink caffeine, and it falls when you rest or sleep. These temporary changes are completely normal and expected. The concern arises when blood pressure remains elevated consistently, even during rest. That sustained elevation is what defines hypertension and is what can cause long-term damage to the body.

Understanding what the numbers mean gives you a foundation for conversations with your healthcare provider and helps you interpret your readings with more confidence.

Blood pressure falls into categories based on your readings, and understanding where yours falls can help you and your provider decide how to move forward.

Normal blood pressure is generally defined as a reading below 120/80 mm Hg. Numbers in this range indicate that your heart and blood vessels are not under excessive strain.

Elevated blood pressure falls in the range of 120 to 129 mm Hg systolic with a diastolic reading below 80. This is not yet considered hypertension, but it is a signal that your blood pressure is trending in a concerning direction. People in this range are more likely to develop full hypertension if changes are not made.

Stage 1 hypertension is defined as a systolic reading between 130 and 139 mm Hg, or a diastolic reading between 80 and 89 mm Hg. At this stage, the risk of cardiovascular complications begins to increase meaningfully.

Stage 2 hypertension involves systolic readings of 140 mm Hg or higher, or diastolic readings of 90 mm Hg or higher. This level of blood pressure requires prompt attention from a healthcare provider.

A hypertensive crisis refers to a sudden, severe spike in blood pressure, typically above 180/120 mm Hg. This is a medical emergency that requires immediate care.

Because a single elevated reading does not necessarily mean hypertension, providers typically look at multiple readings over time before making a diagnosis. Home monitoring can also be a valuable tool for tracking trends between appointments.

The phrase "silent killer" is used to describe high blood pressure because it typically causes no symptoms at all, even when it is damaging the body. Unlike many conditions that make you feel unwell, hypertension usually does not announce itself with pain, fatigue, or obvious discomfort.

Some people believe they would feel their blood pressure rising, perhaps through headaches, dizziness, or a flushed face. While these sensations can occasionally occur, they are not reliable indicators of hypertension and are just as likely to have other explanations. Many people with severely elevated blood pressure report feeling completely fine.

Because there are no reliable warning signs, the only way to know if your blood pressure is high is to measure it. This is why regular blood pressure screenings are so important. Blood pressure can be checked at a doctor's office, a pharmacy kiosk, or with an at-home monitor. Routine monitoring is one of the most effective ways to catch hypertension before it has a chance to cause significant harm.

If you have not had your blood pressure checked recently, making it a priority is one of the simplest and most meaningful steps you can take for your health.

High blood pressure does not usually have one single identifiable cause. Most cases develop gradually over time as a result of a combination of factors. This type is called primary or essential hypertension, and it is by far the most common form.

Several factors are known to contribute to primary hypertension:

• Age: Blood pressure tends to rise as people get older because arteries gradually become stiffer and less flexible over time.
• Family history: Hypertension often runs in families, suggesting a genetic component.
• Body weight: Carrying excess weight places added demand on the heart and increases the volume of blood that needs to circulate through the body.
• Physical inactivity: A sedentary lifestyle is associated with higher blood pressure levels.
• Diet: Diets high in sodium, low in potassium, and low in nutrient-dense foods are linked to elevated blood pressure.
• Tobacco use: Smoking and other forms of tobacco use cause blood vessels to narrow and blood pressure to rise.
• Excessive alcohol: Regularly drinking more than moderate amounts of alcohol has been linked to higher blood pressure.
• Chronic stress: Ongoing stress may contribute to higher blood pressure over time through its effects on the nervous system and hormonal balance.
• Sleep disruptions: Conditions like sleep apnea, in which breathing repeatedly stops and starts during sleep, are associated with high blood pressure.

A smaller percentage of cases are caused by an identifiable underlying condition, such as kidney disease, hormonal disorders, or certain medications. This is called secondary hypertension.

When blood pressure stays elevated for an extended period without being addressed, it takes a serious toll on the body. The heart, arteries, kidneys, brain, and eyes are all vulnerable.

The heart is one of the most directly affected organs. It must work harder than normal to pump blood against the added resistance in the arteries, which over time can cause the heart muscle to enlarge and weaken. This increases the risk of heart failure and other cardiac complications.

The arteries themselves can become damaged. High pressure can cause tiny tears in artery walls, which then attract cholesterol and other substances that build up into plaque. Over time, arteries can become narrow and hardened in a process called atherosclerosis, which restricts blood flow and raises the risk of heart attack.

The brain is also at significant risk. High blood pressure is one of the leading risk factors for stroke, which occurs when blood flow to part of the brain is interrupted. It can also contribute to cognitive decline and an increased risk of dementia.

The kidneys rely on healthy blood vessels to filter waste from the body. Chronic high blood pressure can damage those vessels and impair kidney function, which in turn can make blood pressure even harder to control.

The small blood vessels in the eyes can also be damaged by high pressure, potentially leading to vision problems.

Diagnosing high blood pressure is straightforward and involves no discomfort. A healthcare provider wraps an inflatable cuff around your upper arm and briefly inflates it before slowly releasing the pressure. The instrument measures both your systolic and diastolic pressures and displays them as a two-number reading.

Because blood pressure can fluctuate, a single elevated reading is generally not enough to diagnose hypertension on its own. Your provider will typically want to see multiple readings taken on different occasions before making a diagnosis. Factors like stress, caffeine, exercise, and even the act of visiting a healthcare setting can temporarily elevate readings.

Home blood pressure monitoring has become a valuable tool. Many providers recommend tracking your blood pressure at home at consistent times of day to build a clearer picture of your baseline numbers. If you are using a home monitor, bring it to your appointment so your provider can verify its accuracy.

Your provider may also perform blood tests, a urine test, an electrocardiogram, or other assessments to evaluate how high blood pressure may be affecting your organs and to look for any underlying causes.

Many of the factors that contribute to high blood pressure are modifiable, which means that daily habits can have a meaningful effect on your numbers.While lifestyle changes are not a replacement for medical care, they are a foundational part of keeping blood pressure in a healthy range.

Some of the most impactful habits include:

• Reducing sodium intake: Eating less salt is one of the most effective dietary changes for lowering blood pressure. Reading food labels, choosing fresh foods over processed ones, and cooking at home more often are practical ways to reduce sodium.
• Eating a heart-healthy diet: A diet rich in fruits, vegetables, whole grains, lean proteins, and low-fat dairy supports healthy blood pressure. The DASH eating plan (Dietary Approaches to Stop Hypertension) is a commonly referenced dietary approach for this purpose.
• Moving regularly: Consistent physical activity, such as brisk walking, swimming, or cycling, supports lower blood pressure. Even moderate amounts of activity make a difference.
• Maintaining a healthy weight: Even a modest reduction in excess weight can have a meaningful effect on blood pressure levels.
• Limiting alcohol: Staying within moderate drinking guidelines can help keep blood pressure from climbing.
• Not smoking: Quitting tobacco supports better blood vessel health and lower blood pressure.
• Managing stress: Practices such as deep breathing, meditation, yoga, and spending time outdoors can help reduce the physical effects of chronic stress.
• Getting enough quality sleep: Prioritizing sleep and addressing disruptions like sleep apnea supports better cardiovascular health overall.

If you have not had your blood pressure checked in the past year, scheduling a check is a good first step, particularly if you are an adult, have risk factors, or have a family history of hypertension.

You should seek care promptly if your blood pressure reading is 130/80 mm Hg or higher on more than one occasion, if your readings are consistently trending upward, or if you experience symptoms such as severe headache, chest pain, shortness of breath, or visual changes. These symptoms alongside elevated blood pressure may require urgent evaluation.

If you have already been diagnosed with hypertension and are struggling to manage it with lifestyle changes alone, or if you have noticed your home readings becoming less controlled, reach out to your healthcare provider. Hypertension is a condition that benefits enormously from consistent, ongoing care and monitoring.