A sleeping heart rate (SHR) measures how many times your heart beats per minute while you are asleep. This metric is distinct from your resting heart rate (RHR), which is measured while you are awake but calm. The SHR is generally the lowest reading achieved throughout a 24-hour cycle, often falling 10% to 30% below your daytime resting rate. Tracking your sleeping heart rate offers valuable insights into cardiovascular health, recovery status, and overall physiological stress.
What Defines a Normal Sleeping Heart Rate
A healthy sleeping heart rate for most adults typically falls within a range of 40 to 70 beats per minute (bpm). This range represents the heart’s recovery period when the body is most relaxed. However, the definition of a “normal” rate is highly variable and depends significantly on age.
The heart rate naturally decreases from infancy to adulthood. Newborns often have a sleeping heart rate between 70 and 190 bpm, while children aged 7 to 9 years typically settle between 70 and 110 bpm.
Once a person reaches adolescence, the range stabilizes, generally falling between 60 and 100 bpm, similar to the adult resting heart rate. For healthy adults, a rate between 40 and 60 bpm is often cited as optimal, reflecting an efficient cardiovascular system. This lower boundary is common in physically fit individuals.
The Science Behind Heart Rate Reduction During Sleep
The slowing of the heart rate during sleep involves a shift in the Autonomic Nervous System (ANS). The ANS manages involuntary body functions and is divided into the sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) systems. When awake, the sympathetic system often dominates.
As you fall asleep, the body transitions to parasympathetic dominance. This shift promotes relaxation, lowers blood pressure, and signals the heart’s natural pacemaker, the sinoatrial node, to beat slower. The body’s metabolic demands also decrease, requiring less oxygen and fewer heartbeats to deliver it.
The heart rate fluctuates across the different sleep stages. During non-REM deep sleep, parasympathetic activity peaks, and the heart rate typically reaches its lowest point. Conversely, during Rapid Eye Movement (REM) sleep, associated with dreaming and increased brain activity, the heart rate can become more variable and may temporarily increase.
Personal Factors That Influence Your Sleeping Heart Rate
An individual’s personal sleeping heart rate is shaped by several non-pathological factors, explaining why a healthy person’s reading may fall outside the general population range.
Physical Fitness
Physical fitness is a major influence, as highly trained athletes often have a lower sleeping heart rate, sometimes dipping to 40-60 bpm. This is due to a more efficient heart muscle that can pump more blood with fewer beats.
Medications and Substances
Certain medications can significantly alter the rate. Drugs like beta-blockers, prescribed for blood pressure and heart conditions, are designed to slow the heart rate and contribute to a lower SHR. Conversely, stimulants used to treat conditions like ADHD, or common substances like caffeine and nicotine, can keep the heart rate elevated throughout the night.
Lifestyle and Environment
Environmental and lifestyle factors also play a role in nocturnal heart activity. Poor sleep quality, resulting from late-night alcohol consumption or high stress, prevents the body from fully entering the deeply restorative phases of sleep. When the body is stressed or fighting off a mild illness, stress hormones or an immune response can lead to a higher-than-average sleeping heart rate.
When Sleeping Heart Rate Signals a Potential Issue
A consistently high or low sleeping heart rate that deviates significantly from a person’s established personal norm may suggest an underlying health concern. For most adults, a rate persistently below 40 beats per minute, unless you are a highly conditioned athlete, can be a sign of an issue. This very slow rate, sometimes called sleep bradycardia, can lead to symptoms like fatigue or dizziness if the heart is not pumping enough blood.
On the other end of the spectrum, a persistently high average sleeping heart rate, often above 80 or 90 bpm, can indicate that the body is under stress. This could be a symptom of conditions like a developing infection, chronic stress and anxiety, or an undiagnosed sleep disorder such as obstructive sleep apnea. Sleep apnea causes brief, repeated drops in oxygen, which triggers a stress response and forces the heart rate to surge.
If your heart rate readings are consistently outside your personal norm, or if you experience symptoms like chest pain, shortness of breath, or frequent palpitations, you should contact a physician. A sustained elevation or drop that is not explained by a recent change in lifestyle or medication warrants a professional consultation. Monitoring your personal trend is more informative than focusing on a single reading, as it helps identify a sustained pattern that requires medical evaluation.