A low heartbeat, medically called bradycardia, is a resting heart rate below 60 beats per minute (bpm). For most adults, a normal resting heart rate falls between 60 and 100 bpm. A rate below 60 isn’t automatically a problem, though. Whether it matters depends on how low it goes, what’s causing it, and whether you feel any symptoms.
When a Low Heart Rate Is Normal
Plenty of people walk around with resting heart rates in the 50s or even 40s and feel perfectly fine. Very fit athletes commonly have resting rates near 40 bpm because their hearts pump blood more efficiently with each beat, so they simply don’t need to beat as often. If you exercise regularly, a heart rate in the low 50s at rest is often a sign of cardiovascular fitness, not disease.
Certain medications also lower your resting heart rate by design. Beta-blockers and calcium channel blockers, commonly prescribed for high blood pressure and other heart conditions, work by slowing the heart and relaxing blood vessels. If you take one of these and your resting rate dips below 60, that’s typically expected. Your heart rate also naturally drops while you sleep, sometimes into the 40s, because your nervous system shifts into a more relaxed state overnight.
Symptoms That Signal a Problem
A low heart rate becomes concerning when your brain and body aren’t getting enough blood flow. The key symptoms to watch for include:
- Dizziness or lightheadedness, especially when standing up
- Fainting or near-fainting
- Unusual fatigue that doesn’t match your activity level
- Shortness of breath with minimal exertion
- Confusion or difficulty concentrating
- Chest discomfort
These symptoms happen because a heart beating too slowly can’t deliver enough oxygen-rich blood to meet your body’s needs. The brain is particularly sensitive to reduced blood flow, which is why dizziness and confusion tend to show up first. If your heart rate drops below 35 to 40 bpm and you’re experiencing any of these symptoms, that warrants immediate medical attention.
Common Causes
The heart has its own electrical system that controls the timing of each beat. A small cluster of cells at the top of the heart acts as a natural pacemaker, sending electrical signals that travel downward and trigger each contraction. A low heart rate develops when something disrupts this signaling. The two most common electrical problems are sinus node dysfunction (where the natural pacemaker fires too slowly) and heart block (where signals get delayed or blocked on their way from the upper chambers to the lower chambers).
Beyond electrical problems, several other conditions can slow the heart:
- Aging: Heart tissue damage accumulates over time, and the electrical system can gradually wear down
- Heart disease or prior heart attack: Damaged tissue may interfere with electrical conduction
- Underactive thyroid: The thyroid produces hormones that regulate metabolism, including heart rate, so low thyroid output can slow everything down
- Mineral imbalances: Abnormal levels of potassium or calcium in the blood affect the heart’s electrical activity
- Sleep apnea: Repeated breathing pauses during sleep trigger drops in heart rate, sometimes significant ones
- Inflammatory conditions: Diseases like lupus or rheumatic fever can inflame heart tissue
- Medications: Sedatives, opioids, and certain drugs used for heart conditions or mental health can all lower heart rate as a side effect
How Age Affects What’s “Normal”
The 60 bpm threshold only applies to adults and adolescents. Children have naturally faster hearts. A newborn’s resting rate ranges from 100 to 205 bpm, and a toddler’s sits between 98 and 140 bpm. Even school-age children (ages 5 to 12) typically range from 75 to 118 bpm. A rate of 60 bpm would be perfectly normal for a teenager but worryingly low for an infant. By the time someone reaches 13, the adult range of 60 to 100 bpm applies.
How to Check Your Resting Heart Rate
To get an accurate resting heart rate, sit or lie down for at least five minutes before measuring. Place two fingers on the inside of your wrist, just below the base of your thumb, and count the beats for 30 seconds, then multiply by two. Avoid checking right after exercise, caffeine, or a stressful moment, as all of these temporarily raise your rate. First thing in the morning, before getting out of bed, tends to give the most consistent reading. Many smartwatches and fitness trackers also monitor heart rate continuously, which can help you spot patterns over time.
How a Low Heart Rate Is Treated
Treatment depends entirely on whether you have symptoms and what’s causing the slow rate. Asymptomatic bradycardia, meaning a low heart rate with no dizziness, fatigue, or fainting, has not been linked to worse health outcomes. In other words, if you feel fine and your heart just beats slowly, you likely don’t need any intervention.
When the cause is a medication, adjusting the dose or switching to a different drug often resolves the problem. If sleep apnea is driving nighttime drops in heart rate, treating the apnea with a breathing device typically eliminates the slow heart rate and removes any need for further treatment. An underactive thyroid is managed with hormone replacement, which usually brings the heart rate back up as thyroid levels normalize.
For people who do have symptoms tied to a slow heart rate, a pacemaker is the primary treatment. This small device, implanted just below the collarbone, monitors the heart’s rhythm and delivers tiny electrical impulses to keep the rate from dropping too low. There’s no single heart rate number that automatically triggers a pacemaker recommendation. Instead, doctors look for a clear connection between a documented slow rhythm and symptoms like fainting or severe dizziness. The exception is certain types of advanced heart block, where electrical signals between the upper and lower chambers are severely disrupted. In those cases, a pacemaker is recommended regardless of symptoms because the risk of the heart pausing for dangerously long periods is too high.
Pacemaker implantation is a relatively minor procedure, typically taking one to two hours. Most people go home the same day or the next morning and return to normal activities within a few weeks, with some restrictions on heavy lifting while the incision heals.