Is a Low Heart Rate Dangerous?

A low heart rate can lead to fainting and falls if you’re not a highly trained athlete, but the condition is often treatable.

low heart rate dangerous

Health risks can develop from a low heart rate—a condition called bradycardia.

© Supparsorn Wantarnagon |

A low heart rate may be a sign of an efficiently working heart. Or, if the rate becomes too low, it could be a sign of health complications down the road.

A normal or healthy resting heart rate for an adult is between 60 and 100 beats a minute. A heart rate near the lower end of that range is considered a good sign. Your heart isn’t working too hard to pump blood effectively throughout the body. It’s one indication of cardiovascular fitness. A very rapid heart rate, on the other hand, raises your risk of heart failure, blood clots, and other problems.

But health risks can develop if a low heart rate gets too low—a condition called bradycardia. Bradycardia is usually diagnosed when your resting heart rate is less than 60 beats per minute (BPM). In some cases, the threshold is less than 50 BPM. Those numbers are guidelines. You may experience heart-related complications if your resting heart rate is 65 or 70 BPM. Or, you may be fine with a resting heart rate that is less than 60 BPM. Long-distance runners and other athletes in top cardiovascular health often have a resting heart rate that is under 60 BPM.

If you’re not training for a marathon or swimming dozens of laps every day, you should talk with your doctor if you notice a low heart rate.

When to Worry About a Low Heart Rate

One complication related to bradycardia is a condition called syncope. It means a loss of consciousness (fainting), usually due to insufficient blood flow to the brain. A low pulse rate can compromise your circulation. Your heart may not pump fast enough to keep a healthy flow of blood up to your brain and throughout your body. Fainting, of course, can lead to dangerous falls and bone fractures.

The most common symptoms of a low heart rate, according to the American Heart Association, are fatigue, confusion, dizziness, shortness of breath, especially during exercise.

To compensate for a slowly beating heart, your heart muscle might try to pump harder to keep up with your body’s demand for oxygenated blood. This can lead to high blood pressure (hypertension) and even heart failure, if your heart muscle works overtime for too long a period. A low pulse rate is also paired sometimes with low blood pressure, a condition known as hypotension. Low blood pressure is also a cause of syncope.

However, research suggests that bradycardia does not increase the risk of cardiovascular disease—the precursor to a heart attack. A study led by Ajay Dharod, MD, an internal medicine specialist with Wake Forest Baptist Medical Center, found that a low heart rate by itself does not suggest an inevitable slide toward heart disease. “For a large majority of people with a heart rate in the 40s or 50s, who have no symptoms, the prognosis is very good,” Dr. Dharod says. “Our results should be reassuring for those diagnosed with asymptomatic bradycardia.”


If you have bradycardia, but not other symptoms, you may not need any treatment. But if you do start to experience fainting or even frequent episodes of feeling lightheaded, or you start to experience chest pain, tell your doctor. If treatment is necessary, your doctor will need to determine the cause first.

In many cases, bradycardia is caused by problems with the sinoatrial (SA) node. This is sometimes referred to as the heart’s “natural pacemaker.” The SA node is a cluster of cells in the upper part of the heart that sends out electrical signals that help control the beating of your heart. If the SA node is damaged or is otherwise not working properly, your heart rate can slow down, speed up, or become inconsistent. An abnormal heart rate of any type is called an arrhythmia. If the problem is serious enough, you may require a pacemaker. This small device is implanted in the chest. When it detects an arrhythmia, it sends an electrical signal to the heart to help restore a healthy rate.

Common causes and risk factors of bradycardia are old age, heart block, and damage from heart disease or heart attack. Another common cause is thyroid disease. Low thyroid function (hypothyroidism) can cause a number of health problems, including low heart rate. Controlling your thyroid disease with medication and lifestyle changes may help correct bradycardia.

A low heart rate may also be a side effect of certain medications, such as digoxin, a common drug used to treat heart failure. Beta blockers, which are often prescribed to treat high blood pressure or tachycardia (abnormally fast heart rate), may also cause your heart to beat too slowly. “Bradycardia may be problematic in people who are taking medications that also slow their heart rate,” Dr. Dharod says. “Further research is needed to determine whether this association is casually linked to heart rate or to the use of these drugs.”

Adjusting your medication dosage may be enough to reset your heart rate.

Measuring Your Heart Rate

Checking your resting heart rate isn’t difficult. Start by sitting quietly for five minutes or so. Then, place two fingers on the thumb side of your wrist, between the bone and the tendon over your radial artery. Once you feel a pulse, count the number of beats for 15 seconds. Then multiply that number by four. That will give you your beats per minute.

It’s a good idea to do this every so often, just to have a baseline number. If you notice a change—up or down—tell your doctor at your next appointment. You should also talk with your doctor about your target heart rate, particularly if you are an older adult or you have risk factor for cardiovascular problems, such as diabetes, family history of heart disease, smoking, obesity, a sedentary lifestyle, or high blood pressure.

Keep in mind that your heart rate should go up when you exercise and then return to a normal resting heart rate soon after you stop. If your heart rate doesn’t rise very much or takes a long time to return to normal, tell your doctor. It may be a sign of a heart that isn’t working optimally. It may not be serious, but it is worth a discussion with your physician.


This article was originally published in 2018. It is regularly updated. 

As a service to our readers, University Health News offers a vast archive of free digital content. Please note the date published or last update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

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Jay Roland

Jay Roland has been executive editor of Massachusetts General Hospital’s Mind, Mood & Memory since 2017. Previously, he held the same position with Cleveland Clinic’s Heart Advisor, since 2007. In … Read More

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  • I happened to be in the hospital in a unit hen my heart rate and blood pressure could not even be read either by the machine or manually when they finally could get a faint heart rate reading it was going from 5-10 bpm I was hooked up to the crash cart after a few hours and no luck getting my rate higher they admitted and brought me up to a room where I was watched 24/7 it also car back my potassium was a3.2 and my disgusting level was very low anyway my heart rate is always low any suggestions

  • I was admitted into the hospital while being taken there by ambulance they couldn’t get a blood pressure read or even a heart beat read they were way to low they had the crash cart ready my pressure was extremely low and my heart rate was going from 10 to 5 beats per minute I was admitted and had someone sit and watch me 24/7 the nurses were nervous they said I belonged in ICU I have no idea why I now suffer from bradicardia I just want to know what to look for and what I should do I’m 48 years old and in my family my uncle my grandfather and grandmother also my mom had heart conditions but my uncle and grandfather both passed before their 49th birthday also during my stay I was told by 4 doctors tell me to go see neuro and get tested for early onset dimentia I do also have a number of health issues to me the bradicardia is #2 on the list cause I’m always in the 30-60 range and when the doctor said I might need to have a pacemaker put in why didn’t they when I couldn’t get past a20 for my hospital stay any one can give me information please

  • Get your PCP to test your Thyroid Function. Untreated Hypothyroidism can cause Bradycardia….and even Tachycardia. It can have profound effects on the cardiovascular system.

  • Lifetime pulse of 48 to 50. At age 65 almost passed out at work. Pulse was 32 when checked, feeling normal. Went to urgent care, pulse was 35 with EKG and blood test. Sent home, told to go to emergency room if dizzy. We’ll call you for cardiologist apt. 5 days later I passed out without warning, fell 18 ft, broke 10 ribs, clavicle, ruptured lung and spleen, broke vertebrate in neck and chest. I have a pacemaker set at 50 now.

  • My heart rate goes down up to 35 while awaking. Slows down even further during sleep. Agun sometime found 72. Pls advise.

  • that is low.however difficult to explain without further details of any conditions you have or medications that you are taking. Sometimes just changing the times you take your medications can improve this condition. Speak to your doctor urgently. Also spicy food,coffee, a bit of excercise can increase your heart rate.However you need to investigate your condition urgently.

  • I hope this information may help someone. But please speak to your doctor first. IF you are taking several medications for your bp, and then it may be possible not to take them all in the morning for instance, especially if your BP and heart rate drops and you feel breathless..sometimes a smaller dose can make all the difference or taking some of those medications a bit later, say after lunch..check with your doctor , even a phone consultation..

  • My question is for a 64 year old male. He’s on 25mg of losartan daily, and takes allopurinol for gout. His heart rate drops to low 30’s, and he feels very fatigued. He’s been taking naps in the middle of the day, when he never has done so before (unless he’s sick). He’s been evaluated by a cardiologist for bradycardia, but because he doesn’t have an arrhythmia, they say he’s fine, and has “the heart of an athlete.” He’s not by any means athletic… At what point does he need to be in order to receive further treatment? He’s already exhausted, and has really low heart rate, even dropping in high 20s at times. He works as a truck driver, and so doesn’t have much opportunity for exercise since he drives for work. Also, can having bradycardia (to the point he has) eventually lead to CHF? Due to the pooling of blood in the heart chambers? I’m very concerned, and am not sure what to do at this point. He has another appointment scheduled with his cardiologist, but I fear he’ll say the same thing, as he recently had a 24-hour holter monitor in August of this year showing the same: bradycardia (lowest at 27bpm) with no arrhythmia. What I can say is that he has not had any syncopal or near syncopal episodes, no chest pain, no shortness of breath, and no palpitations. Please, any advice, or further clarifications would be very much appreciated. Thank you.

  • I am female 65 years with high cholesterol 8.3 HDL 1.55 LDL 5.50 Tri 1.7 and a Calcium Score reading of 480. Doctor put me on Atorvastatin 20mg. Cholesterol reduced after 10 months to 5.1/1.8/2.55/1.0 readings relevant to above readings. I had a recent review of medication and re-script and my blood pressure was 127/77 but my heart rate was only 42. I am going to have a Echocardiogram and have had blood tests.

  • My father blacked out for a few seconds on 22nd November, 2018. He felt dizzy after coming back to sense. We called a doctor who checked his pulse rate and found it is around 38. ECG on 23rd showed it’s around 35. The next day the doctor checked again and found it around 32. He has been admitted to the hospital today. Am concerned about his condition particularly since he has prostate problem, hypotension, arterial blockage, mild thyroid. Is pacemaker the only solution for him?

  • Hello, Sayantani. We’re sorry to hear about your father’s dizzy spell and wish him well as he receives the medical care he needs. Regarding your question about a pacemaker: We obviously can’t make that determination but can at least point you in the direction of our primer on how pacemakers work and when they’re necessary; it was written by longtime health writer Dan Pendick, and it’s here if you want to take a look:

    We also have a post on causes of dizziness that may help you. It was written by our contributing medical editor, Dr. Leonaura Rhodes, and it’s here:

    Good luck! —Larry Canale, UHN

  • I am looking for a detector or alarm device that can be worn daily that would sound off an alarm to indicate to the wearer of the device that his pulse is low (preset the desired low pulse number)at which he can take action
    ie, increase fluids, pull off the road when driving etc. any watch like device out there for this need?

  • Great post. I was checkin contnuously this blog and I’m impressed!
    Extremely helpful information specifically the last part :
    ) I care for such information much. I was looking for this
    particular info for a long time. Thank you and best of luck.

  • I have a ridiculously low heart rate. It had a never caused me any problems until i suddenly fainted. I broke my neck when I collapsed. I am now a quadriplegic. It happened when I was 53. I am now 61. I have learned to cope, but i almost died as a result when the attending first responders couldn’t get my heart rate up to speed. I haven’t had any difficulties since. But i have just been refused elective surgery. They basically laughed in my face when they claimed they couldn’t guarantee to keep my heart rate up high enough to keep me alive after putting me under an anisthetic. Oh well. I will get my thyroid gland checked.

  • My resting pulse has been in the 40s for decades, and was as low as 43 BPM when I was arguably in my best shape ever in my early 30s. I am definitely not an elite athlete of any kind, although I do walk an average of 4 mi/day at a 13-14 min/mile (4+ mph) pace and lift weights at the gym for 20-35 min. 3 days/week. I suspect sub-60 BPM heart rates are more common and normal than your article might indicate. I definitely do not worry about mine being too low.

  • I’am nearly 70..male.. and my pulse over the past 15 years is between 42 and 52 .
    I do brisk walking most days and my pulse gets up to 120 and drops back to low 50s soon after walk.
    Iam on 4 bp meds and feel my bp is too low at times going down to 98 over 58 that’s when I sometimes feel a bit faint when getting up suddenly. bp below 120 most of the time and feel really great.

  • Am asking a question for my fiance. He woke up and wanted to urinate and immediately he got to the bathroom he fainted and stood up all my himself like a minute later. He said he’s heart beated so hard for two times and he didn’t know what happened next. Since then, most times he feels strenghtless and says it’s like the fall wants to repeat itself. He has never been sick. But he once visited his doctor some years back and was told his heart was slow but the doctor said it’s the best condition that he doesn’t need any treatment. Please I need help, whats the cause of the recent happenings?

  • I was given an Apple Watch for Christmas and have noticed that my resting heart rate is around 53 bum. I work 3200 feet above sea level, I am 57 years young and a bit overweight. I do rarely feel light headed an sometimes feel hypertensive. Am I overthinking that I have an issue? I was putting these symptoms down to the elevation and thinner air quality.

  • I recently fainted in mid January. An echo taken a week later showed sinus bradycardia and nonspecific T wave abnormality. I just recently had a halter monitor and reg bit results aren’t in. I have dull headache all day, feel dizzy. My body feels sluggish and my legs heavy. My heart rate is from 58 to 62 and I’ve noticed I sometimes feel worse when my blood pressure is normal like 121/75 70. I’m running late for work because don’t feel well. It’s causing me to miss work and I’m a veteran so it takes forever to be diagnosed. How do I control my symptoms?

  • Hello I recently buy an apple watch and I noticed when i sleep my heart beat go down just once to 34 this is normal? My average is 49 in sleep by the clock i am very Worried thank you It’s important to note that I work physically and my bmi is 19.1 thank you.

  • My grandma age 70.Due to some attack of flu,severe cold and cough the mediations and antibiotics she told made her body weak to extent of hard to breath.After doctor diagnosis She is having hypothyroid ,Swelling in legs , lower heart rate, low blood and sudden attack of fever .she is under monitoring in ICU what treatment will be helpful …?
    Is the pacemaker surgery help her to lead normal life?please help

  • My usual hr in the morning before i get out of bed is 53-55 bpm. Yesterday i had an elevated bp of 160/100. Feeling so fatigued that i lie in bed for almost a day. Im having hot flashes and bp is 140/90 but my pulse rate is between 48-53. Im not on hypertensive meds what does this indicate?

  • try rehydrating with electrolyte supplement and B12 vitamins, also, apple cider vinegar (organic) brings down BP – NOTE: I am NOT a doctor

  • sorry – for electrolyte supplement i DO NOT mean gatoraide. Try to find something without sugar or maltodextrin

  • I am a fit man of 66. I have started to get into distress when out running after about 4K; as i was comfortable doing 10k’s and half marathons it is not due to fitness. My heart rate drops like a stone from 140 to 80 to 90 and does not rise again. My body goes into distress mode and i have to stop running and it can take hours to recover. My resting heart rate is in the low 40’s dropping to 40/42 when totally relaxed. I have now started to have many periods of feeling faint when standing. My heart rate drops to 26 to 32, my low blood pressure drops well below 60 often in the 40’s my high blood pressure fluctuates between 80 and 150. The main question is what is causing my heart rate to drop so much that it is well below my resting heart rate.

  • I’m 72 and currently have a heart rate in the low 30’s on waking. It has gone as low as 18. I feel exhausted. I have had a cardiac monitor implanted for a year or so with a view to possibly fitting a Pacemaker but so far have been told it’s ‘complicated’ and I’m also aware the device costs £15,000 and the NHS hesitates about spending money like that on 72 year olds. Currently I’m told Yes, I ‘probably’ need one but it’s still ‘complicated’. I’ve been told if I had PMI it wouldn’t be an issue. My usual heart rate is rarely over 50 and normally about 42. I’m so exhausted I can’t raise the energy to get up to the hospital! Any advice guys?

  • Hi, my resting Pulse rate is between 63-75. But today it showed 58. I feel weak sometimes, and have a sedentary job..please advise

  • My BP often drops to the mid 40s, both systolic and diastolic, heart rate between low 40s to low 50s when try to recline and sleep at night. I get a very intense anxious feeling when this happens which will wake me if sleeping. I also have the feeling that I am swaying 24/7 whenever I move my head, to the point that I cannot stand, walk without a walker. I have “attacks” where this horrible feeling become very intense, I cannot stand by myself, I am very nauseous, have whole body trembling, hot flashes and flushing, erratic blood pressure. I sometimes end up in the ER. I was tested for POTS twice. The first time was positive, the second time negative. I definitely have syncope, but a pacemaker is not an option because I get physical warnings before I pass out so I can lay down. I am in the care of 3 neurologists who have been unable to diagnose my issue. It has exacerbated considerably in the past year since I weaned off opioids which were prescribed for chronic pain for over 12 years. Do you have any idea what might be causing the swaying and attacks?

  • I have Hashimotos syndrome (hypothyroidism), also left axis deviation and a resting pulse of 51, are these connected?

  • Does bpm go down just before having a seisure. And is there some type of watch thT would signal me so i coul pull off the road or put myself in a protected area?

    • Hello, we’re unable to provide specific medical advice, so it’s best to contact your doctor. Thanks for reaching out and good luck!

  • Oh the joys of growing older – my resting pulse is 44 …. my doctor is not pleased. Asks regularly “ do you experience dizziness or fainting?” I do not – yet. I take medication for BP – my favorite was a beta blocker. Sadly missed. I was told it wasn’t helping my pulse. My only system is naps, which I also adore. My question is > will i develop further symptoms ? The idea of a pacemaker does not thrill – I would probably pass on during the procedure.
    I dislike driving, so your all safe there.
    Thank you for your time. A nap is now in order.

  • For those of you experiencing bradycardia while asleep (as recorded, for example, by a wrist fitness monitor), you might want to be screened or checked for sleep apnea. That is one condition that can cause bradycardia while sleeping and is not mentioned in this article.

  • BP runs 120/65 bradycardia rate average 53-55, a few higher to58 a few lower to 48. My cardiologist always panics. I did have a CABG 3 years ago, take an ARB & beta blocker but am in excellent health otherwise. Work out 45 minutes a day. Do have occasional PVC’s and had them all my life now at 67. Cardio talks about a pacemaker? I am not quite getting that. No symptoms of any problems (no fainting, shortness of breath) etc

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