What’s the Difference Between a Normal and Dangerous Heart Rate?

What’s the Difference Between a Normal and Dangerous Heart Rate?

Whether due to stress or an intense cardio workout, most of us have felt our heart racing from time to time. A rise in your heart rate can be perfectly normal given outside circumstances. However, there are some times when you feel like your chest is pounding and you wonder “what’s a dangerous heart rate?”

Your heart rate is the number of times your heart pump beats per minute to do its job, which is to circulate blood (to provide oxygen and nutrients) to the rest of the body, says Puja Mehta, M.D., director of Women’s Translational Cardiovascular Research at the Emory Women’s Heart Center and member of the Women’s Heart Alliance Scientific Advisory Board. How we define whether a heart rate is normal or dangerous depends largely on your own average beats per minute.

Meet the Experts: Ronald Freudenberger, M.D., physician in chief at Lehigh Valley Heart and Vascular Institute; Puja Mehta, M.D., director of Women’s Translational Cardiovascular Research at the Emory Women’s Heart Center and member of the Women’s Heart Alliance Scientific Advisory Board. Brett Victor, M.D., F.A.C.C., cardiologist at Cardiology Consultants of Philadelphia; Paul Wang, M.D., director of the Stanford Cardiac Arrhythmia Service and American Heart Association Go Red for Women volunteer.

So, what is a normal heart rate and what is cause for concern? Ahead, learn what happens if your heart rate is too low, too high, and how to stabilize it on your own.

What’s a normal heart rate?

A “normal heart rate” for adults ranges from 60-100 beats per minute (bpm), says Brett Victor, M.D., F.A.C.C., cardiologist at Cardiology Consultants of Philadelphia. However, oftentimes lower heart rates can be totally normal, and a well-trained athlete can have a normal heart rate in the 50s or as low as 40 without any cause for concern, he notes.

Normal heart rate varies based on a person’s age, fitness and activity levels, temperature, caffeine, stress, and other risk factors (such as blood pressure, chronic diabetes, obesity, etc), says Dr. Mehta. “It is good to have variability in your heart rates depending on what you are doing. When we sleep, it is normal for heart rates to be lower,” she says. Similarly, sometimes elevated heart rates (especially in the setting of exercise, stress, illness) are expected and normal, notes Dr. Victor.

Children generally have higher heart rates—newborns can range from 70-190 bpm and these averages decrease as they approach school-age to 70-110 bpm, and further decline into adulthood, explains Dr. Mehta.

What’s a dangerous heart rate?

When we detect heart rates over 90 bpm at rest, that can indicate a sign that something else is at play, such as anemia, dehydration, or even thyroid disease, says Ronald Freudenberger, M.D., physician in chief at Lehigh Valley Heart and Vascular Institute. “People who have heart rhythm disturbances also can have a high heart rate—the most common being atrial fibrillation, or AFib,” he notes.

With the exception of being a well-trained athlete or being asleep, a sustained heart rate less than 45 or greater than 110 may indicate a heart rhythm issue that is worth getting checked out, adds Dr. Victor.

What happens if your heart rate is too high?

A resting heart rate greater than 100 bpm in adults should be discussed with a healthcare professional to identify the cause, says Dr. Mehta. Tachycardia is when your heart rate is higher than normal, she explains. “Untreated, if there is too much tachycardia for too long, it can put excess strain on the heart muscle by overworking it and it can cause abnormal heart enlargement and weakening of the heart,” she notes.

What happens if your heart rate is too low?

Bradycardia is when your heart rate is too low, which can make people feel faint, dizzy, short of breath, and fatigued, notes Dr. Mehta.

If your heart rate is slow and you feel dizzy and that you are about to pass out, it is important to see a doctor right away, says Paul Wang, M.D., director of the Stanford Cardiac Arrhythmia Service and American Heart Association Go Red for Women volunteer. “Some people may even need a pacemaker, which is a device placed in the body which keeps the heartbeat from getting too slow,” he explains.

What heart rate is an emergency?

If your heart rate is too high or too low, this can lead to a drop in your blood pressure, which can in turn lead to passing out, says Dr. Victor. “A heart rate less than 35 beats per minute or greater than 150 beats per minute (at rest) should be considered an emergency,” he notes.

High heart rates with associated symptoms such as chest tightness, palpitations or heart pounding/racing, fainting, dizziness, lightheadedness, shortness of breath, or fatigue, it may suggest an arrhythmia and is an emergency, adds Dr. Mehta. If you experience any of these symptoms with a high heart rate, seek medical attention.

How to stabilize your heart rate

The most efficient way to lower your heart rate is through breathing, says Dr. Wang. “Deep exhalations can decrease your heart rate. Breathing in through the nose for the count of 4, holding it, and then exhaling deeply for the count of 6 can be effective.” If you are not successful in bringing your heart rate down with breathing techniques, see your doctor or go to the emergency room for evaluation, Dr. Wang advises.

Sometimes, heart rates can be elevated because of anxiety, says Dr. Victor. “In some cases, just relaxing and taking deep breaths can bring down these fast rates and if they do, it probably means there is no urgent heart problem.” Likewise, if a slow heart rate goes up with walking, that usually means there is no cause for concern either, he notes.

Long term, one of the most effective habits you can make to lower your heart rate is by exercising routinely and regularly, says Dr. Wang. “Consistent exercise stimulates the parasympathetic nervous system, which leads to a lower resting heart rate. Yoga, meditation, and breathing exercises also stimulate the parasympathetic nervous system and can lead to an overall lower heart rate.”

Dr. Freudenberger agrees that aerobic exercise is the key to regulating your heart rate and is great for cardiovascular health overall. “Those who exercise regularly, including most athletes, have lower resting heart rates and that’s normal. Alternatively, if you are not getting regular exercise, your heart rate will go up quickly when you are active or exercising,” he notes.

When to see a doctor about your heart rate

There is significant variability among the population with regard to heart rate, so it is important to know your personal “normal” and seek medical attention if you notice a significant difference from your baseline without an obvious cause, says Dr. Victor. “More importantly, if a change in heart rate is accompanied by symptoms such as lightheadedness, passing out, heart flutters or palpitations, shortness of breath, or chest pain, this requires immediate medical attention.”

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