A healthy adult’s heart rate during sleep typically falls between 40 and 60 beats per minute (bpm), though some sources place the upper end closer to 75 bpm. That’s noticeably lower than the standard daytime resting range of 60 to 100 bpm. The drop happens because your nervous system shifts into a more restful mode once you fall asleep, reducing the demands on your heart.
What Counts as Normal by Age
Your sleeping heart rate is closely tied to your daytime resting heart rate, which changes throughout life. Resting heart rate generally decreases as you age from childhood into your 50s and 60s, then levels off. Here’s what typical daytime resting rates look like across age groups:
- Newborns: 107 to 164 bpm
- 1 to 3 years: 92 to 140 bpm
- 4 to 8 years: 74 to 117 bpm
- 8 to 15 years: 62 to 103 bpm
- 18 to 30 years: 65 to 96 bpm
- 31 to 50 years: 61 to 94 bpm
- 51 to 70 years: 60 to 87 bpm
- 71 to 80 years: 63 to 85 bpm
During sleep, expect these numbers to drop. Children aged 6 to 8, for example, have awake resting rates of 74 to 111 bpm but sleeping rates closer to 67 to 89 bpm. Adults see a similar proportional dip. If your wearable shows a sleeping heart rate roughly 10 to 20 bpm below your typical daytime resting rate, that’s generally in the expected range.
How Sleep Stages Affect Your Heart Rate
Your heart rate doesn’t stay flat all night. It fluctuates as you cycle through different sleep stages, and understanding this explains why your smartwatch graph looks like gentle rolling hills rather than a straight line.
During deep sleep (non-REM stages), your body’s “rest and digest” nervous system takes over. Research published in the American Heart Association’s journal Circulation found that this shift significantly increases the calming, parasympathetic influence on your heart. The ratio of stress-related to calming nervous system activity drops from about 4:1 while you’re awake to roughly 1.2:1 during deep sleep. This is when your heart rate hits its lowest point of the night.
During REM sleep, the stage associated with vivid dreaming, that balance flips back. Sympathetic (stress-related) nervous system activity rises to levels comparable to wakefulness, pushing your heart rate variability pattern to look more like it does when you’re awake. Interestingly, the average heart rate itself doesn’t change much between REM and non-REM sleep. What changes is how variable and irregular the beat-to-beat rhythm becomes. REM sleep produces more erratic heart rate patterns, which is completely normal.
Why Athletes Have Lower Numbers
If you exercise regularly, especially endurance activities like running, cycling, or swimming, your sleeping heart rate will likely sit at the lower end of the range. Athletes commonly have daytime resting heart rates in the 40s or 50s, and their sleeping rates can dip even further. This happens because aerobic training strengthens the heart muscle, allowing it to pump more blood per beat and work less hard at rest.
On the flip side, people who are mostly sedentary tend to have resting and sleeping heart rates toward the higher end of normal. If you start a regular exercise routine, you’ll likely see your sleeping heart rate trend downward over weeks and months. Many people use this metric from their wearables as a simple fitness benchmark.
What Pushes Your Sleeping Heart Rate Up
Several everyday factors can elevate your heart rate at night, even when nothing is medically wrong. Alcohol is one of the most common culprits. Having more than two drinks increases your heart rate for up to 24 hours afterward. Even moderate drinking can keep your heart rate elevated for roughly half that time. A single drink has a limited effect, raising your rate for about six hours.
Stress, anxiety, and poor sleep hygiene also play a role. If you’ve been going through a stressful period, you may notice your overnight heart rate creeping up by several beats per minute. Caffeine consumed too late in the day, eating a heavy meal close to bedtime, and sleeping in a warm room can all have similar effects. Illness and fever reliably raise sleeping heart rate too, which is why some wearable devices now flag overnight heart rate spikes as a potential early sign of infection.
When a Low Sleeping Heart Rate Is Normal
Seeing a heart rate in the low 40s or even high 30s on your sleep tracker can be alarming, but it’s often perfectly fine. According to American Heart Association guidelines, heart rates below 40 bpm and pauses longer than 5 seconds occur during sleep across a wide age range in healthy people. These events are driven by the vagus nerve, which naturally slows the heart during rest, and they don’t require treatment in the absence of symptoms.
The key distinction is whether a low sleeping heart rate comes with daytime symptoms like dizziness, fainting, unusual fatigue, or shortness of breath. A fit 30-year-old whose heart dips to 38 bpm during deep sleep but who feels great during the day has nothing to worry about. The same number in someone experiencing lightheadedness or exercise intolerance tells a different story.
When a High Sleeping Heart Rate Matters
A sleeping heart rate that consistently stays above 75 to 80 bpm, or one that’s notably higher than your personal baseline, deserves attention. Some possible causes include thyroid disorders (an overactive thyroid speeds the heart), sleep apnea (which triggers repeated stress responses throughout the night), and abnormal heart rhythms. Heart palpitations at night are most commonly caused by anxiety, stress, or stimulants, but they can occasionally signal an arrhythmia.
The most useful thing you can do is track your trend over time rather than fixating on a single night’s reading. A gradual upward drift in your average sleeping heart rate over weeks, without an obvious explanation like illness or increased stress, is more meaningful than one bad night after a late coffee. If your sleeping heart rate is persistently 20 or more bpm above what’s typical for you, that pattern is worth investigating.
How to Check Your Sleeping Heart Rate
The easiest method is a wrist-worn fitness tracker or smartwatch, which uses optical sensors to measure your pulse continuously overnight. Most devices will show you a nightly average, a resting heart rate (usually the lowest sustained rate), and sometimes a graph broken down by sleep stage. These optical sensors aren’t as precise as a medical-grade ECG, but they’re accurate enough to track trends and spot significant changes.
If you don’t have a wearable, you can get a rough estimate by checking your pulse immediately upon waking, before you sit up or reach for your phone. Place two fingers on the inside of your wrist or the side of your neck, count beats for 30 seconds, and double the number. This won’t capture your true sleeping rate, which is lowest during deep sleep hours before dawn, but it gives you a reasonable proxy for your resting baseline.