What is Blood Pressure?

Blood pressure is the constant pressure against your blood vessel walls. You have likely had your blood pressure taken when you have visited your doctor. He or she probably read off some numbers, one over the other (such as 115/75), but do you know what they mean?  

The first number is systolic blood pressure, which happens when your heart beats. The other is diastolic blood pressure, which is your blood pressure when your heart rests between beats.

High blood pressure is measured as 130/90 or above. Normal blood pressure is less than 120/80. Low blood pressure is below 90/60.

High blood pressure can cause serious health issues, especially for your heart. The American Heart Association estimates that nearly half of U.S. adults have high blood pressure. Some may not even know it.

High blood pressure has few outward symptoms and is sometimes called “the silent killer”. That is why it is so important to get your blood pressure measured regularly. You don’t have to wait to go the doctor’s either. With the right skills and equipment, you can measure your blood pressure at home.

High Blood Pressure and Heart Attacks

One leading cause of high blood pressure and heart attacks is that nasty buildup of plaque in your arteries. This is made of fats, cholesterol, and other substances. This leads to atherosclerosis—when the buildup causes you arteries to harden and narrow. With a much narrower pathway, the heart has to work harder to get blood to flow through the blood vessels.

High blood pressure can damage the blood vessel walls over time. And plaque buildup can eventually break away from artery walls and cause clots. This blocks blood (the oxygen and nutrients it carries) from getting to your heart.

When the heart is starved of the blood and oxygen it needs, a heart attack occurs.

The American Heart Association reports that 69% of people who have a first heart attack have blood pressure higher than 140/90 (as of 2013).

To reduce your risk of a heart attack, it is important to keep your blood pressure at a normal level.


What happens to blood pressure during a heart attack?

Arterial blood pressure checking concept

Just as your blood pressure can affect your risk of a heart attack, a heart attack can affect your blood pressure. Some people experience dramatic shifts in blood pressure.

Some people have lower blood pressure when they have a heart attack. This is possibly because

  • Damaged tissue causes the heart to pump less blood
  • Your nervous system may trigger a drop in blood pressure in response to pain
  • The parasympathetic nervous system goes into overdrive

Others might experience high blood pressure during a heart attack. This is probably because hormones like adrenaline spike, naturally raising blood pressure.

Still others see no change in blood pressure.

Is a shift in blood pressure a sign of a heart attack?

Because your blood pressure may not even shift during a heart attack, it is not a reliable sign. Still, it is important to monitor blood pressure regularly.  

Seek immediate medical help if your systolic blood pressure (the top number) is over 180 or lower than 80 and/or if your diastolic blood pressure (the bottom number) is over 110 or lower than 50.

Learn to recognize other symptoms and signs of a heart attack, which include:

  • Chest pain
  • Pain in the arms (or one arm, usually the left)
  • Jaw, neck, and upper back pain
  • Cold sweats
  • Abdominal pain
  • Nausea
  • Dizziness
  • Fainting
  • Shortness of breath