You may notice this combination when you’re exercising or after standing up too fast

Your blood pressure is low, your heart’s racing and you aren’t feeling your best. What exactly is going on? And how concerned should you be?

Heart rhythm specialist Tyler Taigen, MD, explains what it means when you have a high heart rate and low blood pressure.

Why this happens

So, what’s actually happening inside your body when your heart rate and blood pressure are fast and low, respectively?

Dr. Taigen explains that your heart’s electrical conduction and blood pressure control systems may not be working correctly.

“When your heart is going too fast — meaning anything over 100 beats per minute when you aren’t under physical or emotional stress — it often can’t adequately fill with blood,” he says. “If, in addition to going too fast, your heartbeat is also irregular, the chaotic electrical signaling causes your heart muscles to be out of sync between the top and bottom chambers.”

The consequences of that mismatch? “Less efficiency in your heart means less blood is pumping through your body, which can cause low blood pressure,” Dr. Taigen summarizes.

Oftentimes, this combo is a temporary hiccup. But for people with certain underlying medical conditions, it can become a chronic concern.

Causes

There are lots of possible reasons you may experience a high heart rate (tachycardia) and low blood pressure (hypotension) at the same time. And only some of those reasons require medical treatment. Common causes include:

Possible serious causes include:

Symptoms of a fast heart rate and low blood pressure

When your blood isn’t circulating effectively, it can deprive your organs and tissues of oxygen. But how do you know if it’s happening in the moment?

Signs of an elevated heart rate with hypotension include:

Untreated, a rapid pulse and low blood pressure can cause you to faint. Passing out, also known as syncope, can happen for all kinds of reasons. Unless you’ve been diagnosed with a condition that causes fainting, like POTS, treat losing consciousness as a medical emergency. It’s better to be safe than sorry.

When is this combo a cause for concern?

A momentary episode of low blood pressure and a high heart rate that has a clear cause (like standing up too fast) is nothing to be concerned about. But if it’s happening for extended periods of time, or it happens frequently, Dr. Taigen says it’s important to talk with a provider.

Left unchecked, heart rhythm problems that affect your upper heart chamber (atrium) can put you at an increased risk for stroke, heart failure or death.

Tracking your blood pressure and heart rate

Tracking your heart rate and blood pressure in a symptom journal can help your doctor determine whether there’s an underlying condition causing your heart to race and your blood pressure to dip.

You can track these numbers by:

Your resting heart rate becomes a source of concern when it goes above 100. Your blood pressure works a bit differently. What matters isn’t the number; it’s how much that number changes over a short period of time. You’re experiencing a dangerous drop in blood pressure if:

  • Your systolic blood pressure (the top number on a monitor) drops by 20 mmHg or more
  • Your diastolic blood pressure (the bottom number on a monitor) drops by more than 10 mmHg

If you notice that your heart rhythm and blood pressure aren’t where they need to be, or if symptoms are affecting your ability to function, get checked out. Your healthcare provider will help you get the care you need to keep every part of your cardiovascular system steady and stable.