Blood pressure is the force of your blood as it’s pushed from your heart and circulated throughout your body. During a heart attack, the blood flow to a portion of your heart is blocked. Sometimes, this can lead to your blood pressure decreasing. In some people, there may be little change to your blood pressure at all. In other cases, there may be an increase in blood pressure.
Any blood pressure changes that may occur during a heart attack are unpredictable, so doctors generally don’t use them as a sign of a heart attack. While there could be changes in your blood pressure during a heart attack, other types of heart attack symptoms are much more pronounced.
Blood pressure is measured by evaluating the pressure that blood flowing through your arteries exerts on the walls of those arteries. During a heart attack, blood flow to part of your heart muscle is restricted or cut off, often because a blood clot blocks an artery. Without the necessary blood supply, the affected portion of your heart does not get the oxygen it needs to function properly.
Sometimes, blood pressure can decrease during a heart attack. Low blood pressure is also known as hypotension. Low blood pressure during a heart attack can be due to a few factors:
Your heart pumps less blood because its tissue is damaged: During a heart attack, blood flow to your heart is blocked or cut off completely. This can “stun” or even kill the tissues that make up your heart muscle. Stunned or dead heart tissues reduce the amount of blood your heart can pump to the rest of your body.
In response to pain: The pain from a heart attack can trigger a vasovagal response in some people. A vasovagal response is your nervous system’s reaction to a trigger like extreme stress or pain. It causes a drop in blood pressure and can lead to fainting.
Your parasympathetic nervous system goes into overdrive: Your parasympathetic nervous system (PNS) is responsible for your body’s resting state, in which your blood pressure is lowered. A heart attack can cause your PNS to go into overdrive, decreasing your blood pressure.
Low blood pressure alone isn’t an indication of a heart attack, since not everyone will experience a decrease in blood pressure during a heart attack. In some people, a heart attack may not cause any significant changes in blood pressure at all.
Others may even experience an increase in blood pressure, also known as hypertension, during a heart attack. This may be caused by spikes in hormones like adrenaline that flood your body during stressful situations like heart attacks.
A heart attack can also cause your sympathetic nervous system (SNS) to go into overdrive, leading to blood pressure increases. Your SNS is responsible for your “fight or flight” reactions.
Blood pressure is not an accurate predictor of a heart attack. Sometimes a heart attack can cause an increase or decrease in blood pressure, but having a change in blood pressure reading doesn’t always mean it’s heart-related. Instead, a better strategy for gauging a heart attack is to look at your overall symptoms. A heart attack may cause multiple symptoms, just a few symptoms, or even no symptoms at all.
Chest pain is the most common symptom of a heart attack. However, it’s not the only symptom. Possible symptoms of a heart attack include:
- chest pain
- mild to severe squeezing sensations in the chest area
- pain in the arms (or just one, usually the left)
- cold sweats
- abdominal pain
- jaw, neck, and upper-back pain
- dizziness or fainting
- shortness of breath
These symptoms are often better predictors of a heart attack than blood pressure readings.
Regular checkups with your doctor are key to determining your overall risk for a heart attack. Risk factors can include:
- family history
- personal history of heart attack
- sedentary lifestyle
While a heart attack can’t be predicted, you can work with your doctor to lower the chances of one happening to you.
If I notice a change in my blood pressure, when should I call my doctor?
The answer to this question in some part depends on your normal blood pressure. For example, if your blood pressure normally runs 95/55 and you feel fine, there is no need to worry. If your blood pressure has been running 160/90 and you are having no problems, your medications need to be adjusted, but there is no need to rush to the doctor. You just need a timely follow-up appointment.
In general, however, you need to contact your doctor immediately if your systolic pressure (the top number) is above 180 or lower than 90, or your diastolic blood pressure (the lower number) is greater than 110 or lower than 50.
If you have no symptoms, these readings are less concerning but still need to be addressed fairly quickly. If you have symptoms such as dizziness, blurry vision, chest pain, shortness of breath, or headache along with these blood pressure readings, it’s an emergency and you should seek treatment at the nearest emergency department.Graham Rogers, MDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.