Why Do I Have Low Blood Pressure but a High Heart Rate?

Medically Reviewed By Danielle Hildreth, CPT
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Having low blood pressure and a high heart rate can be normal. However, it can also indicate an underlying condition such as orthostatic hypotension, vasovagal syncope, or atrial fibrillation. If you are experiencing symptoms or feel concerned, contact a doctor. Your blood pressure and heart rate are two important indicators of your health. Blood pressure is the force that pushes blood through your arteries and veins. It is determined by how much blood flows through these vessels at any given time. Heart rate refers to how many times your heart beats per minute. 

Low blood pressure, or hypotension, is a condition in which the blood pressure in the arteries is lower than it should be. The normal range for blood pressure is below 120/80 millimeters of mercury (mm Hg) for many healthy adults. In contrast, a high heart rate, also known as tachycardia, is a heart rate of more than 100 beats per minute in adults. 

This article will discuss the possible causes of low blood pressure with a high heart rate or pulse, its symptoms, treatment, and more.

Can low blood pressure and a high heart rate be normal?

a girl is feeling dizzy in a greenhouse
Anna Malgina/Stocksy United

Yes, it can be normal, and this can happen if you stand up too fast. However, other factors can also cause it. Gravity pulls blood down into your legs and away from your brain when you stand up too quickly. This causes a drop in blood pressure, a condition known as orthostatic hypotension

As a result, your heart rate increases to help the body maintain an adequate supply of oxygenated blood to the brain and other organs. This helps your body compensate for the drop in blood pressure. You may feel lightheaded or dizzy as a result.

Vasovagal syncope

Vasovagal syncope occurs when the vagus nerve sends signals to your body that cause your heart rate and blood pressure to decrease, leading to fainting suddenly. Vasovagal syncope can occur in response to a stressful trigger, such as stress, pain, intense emotion, or the sight of blood.

When vasovagal syncope happens in someone standing up, they may experience lightheadedness or feel faint. Their heart rate drops quickly enough that they can’t get enough oxygen-rich blood to their brain.

Weakening of the heart muscle

A weakened heart muscle is a possible cause of low blood pressure with a high heart rate. It can be caused by disease or damaged heart muscles, making them weaker and less efficient at pumping blood throughout your body.

Other symptoms such as dizziness, fainting, shortness of breath (dyspnea), and fatigue may also be present. Most cases of weakened heart muscle can be treated with medication or surgery.

Neurally mediated hypotension (NMH)

NMH is a condition in which your body has lower than usual blood pressure. It can cause a feeling of warmth, nausea, and lightheadedness before you abruptly lose consciousness, especially when you stand up quickly.

NMH occurs when your brain signals your body to release a hormone called vasopressin, leading to constricted blood vessels and less blood being pumped throughout your body. This causes low blood pressure, but it also makes it harder for your heart to pump enough blood through those tightened vessels, causing a higher heart rate.

Atrial fibrillation

Atrial fibrillation can occur when the heart’s upper chambers, called the atria, beat irregularly. This causes the heart to flutter. It can lead to low blood pressure, high heart rate, and shortness of breath. You may also feel tired or weak.

Atrial fibrillation is often caused by heart disease or injury, which may happen in brief episodes or last for years.

Medications

Many classes of drugs can cause low blood pressure or high heart rate, including:

Various medications affect the heart in different ways, but most will cause an increase in heart rate and sometimes a decrease in blood pressure. Some people can take these medications without any problems, but others may experience dizziness or lightheadedness when they stand up from sitting or lying down too fast.

If you think your medication is causing your symptoms, talk to your doctor about changing or stopping it. Do not make any changes to the medications yourself before consulting with your doctor.

Other causes of low blood pressure and a high heart rate

Many conditions and situations can cause low blood pressure with a high heart rate. Other causes include:

  • Inflammatory processes: These include conditions like rheumatoid arthritis, which can cause inflammation in the body.
  • Heart disease: Conditions like coronary heart disease can narrow or block arteries leading to your heart. This increases your risk of developing a high heart rate.
  • Pericarditis: This condition causes inflammation of the pericardium, a fluid-filled sac that surrounds your heart. In some cases, it can lead to low blood pressure.
  • Atherosclerosis: This disease causes plaque buildup in the walls of your arteries. Over time, this can lead to blockages and low blood pressure.
  • A sudden decrease in body temperature: When the body temperature drops suddenly, this causes the blood vessels to constrict. This causes the blood pressure to drop. When this happens, your heart rate increases to compensate for the drop in blood pressure.
  • Diabetes: This affects the body’s ability to produce insulin, which is necessary for converting glucose into energy and storing it as glycogen. A 2020 study shows an association between diabetes and low blood pressure.
  • Thyroid disorders: These include conditions like an underactive thyroid gland, called hypothyroidism, that can also increase your heart rate.
  • Dehydration: When you are dehydrated, your body loses water. This can lead to many symptoms, including low blood pressure and a high heart rate. 
  • Alcohol and nicotine use: Both alcohol and nicotine are vasoconstrictors, meaning they constrict, or narrow, blood vessels in the body, which can increase the heart rate.
  • Pregnancy: Low blood pressure accompanied by a high heart rate can be expected during pregnancy due to the increased workload to support the baby’s growth and development.

Symptoms of a high pulse and low blood pressure 

Some symptoms of low blood pressure include:

  • dizziness or lightheadedness
  • feeling weak or tired
  • headaches
  • nausea
  • fainting spells
  • trouble concentrating
  • blurred vision or seeing spots before your eyes

When your heart is beating quickly, you may have symptoms such as:

Sometimes, people with a high pulse also experience chest pain or palpitations. If you experience any of these symptoms regularly, see your doctor for a proper diagnosis and treatment plan.

When to see a doctor and how they can help

You may want to see a doctor if you have any of the following symptoms:

  • dizziness or lightheadedness
  • feeling weak or tired
  • shortness of breath
  • blurred or dimmed vision
  • chest pain or discomfort

If you notice that your heart is beating faster than usual regularly or you feel dizzy when standing up quickly, consult your doctor. They’ll be able to figure out what’s causing your symptoms and what treatments might best suit you.

Summary

Low blood pressure with a high heart rate is common and can be caused by various factors. These include vasovagal syncope, atrial fibrillation, weakening of heart muscles, and certain medications, among others. 

If you think that your symptoms may be due to low blood pressure with a high heart rate, see your doctor. They can diagnose the problem quickly before it becomes worse.

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Medical Reviewer: Danielle Hildreth, CPT
Last Review Date: 2022 Nov 30
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.