The heart rate (HR) is a fundamental measure of cardiovascular function, representing the number of times the heart beats per minute. This rhythm fluctuates throughout the day based on activity, emotion, and environment. Resting Heart Rate (RHR) is measured while a person is awake, calm, and settled. Monitoring the heart’s activity during sleep offers an informative perspective on overall health.
The sleeping heart rate is typically the lowest recorded over a 24-hour cycle, reflecting the body’s state of maximum rest and recovery. This nocturnal dip indicates how effectively the body conserves energy. Analyzing this minimum rate can reveal underlying patterns of recovery or stress not apparent during waking hours.
Defining the Ideal Sleeping Heart Rate Range
For most healthy adults, the typical awake resting heart rate falls between 60 and 100 beats per minute (bpm). The sleeping heart rate is expected to be significantly lower than this daytime RHR, often dipping by 10% to 30% during the night. This natural slowdown means a healthy adult’s sleeping heart rate often ranges between 40 and 60 bpm.
Some sources suggest a slightly wider range up to 70 bpm for adults, though the lowest point is frequently observed in the 40s or 50s. For highly conditioned endurance athletes, the sleeping heart rate can fall into the high 30s, reflecting an efficient heart muscle. The “ideal” range is relative to an individual’s baseline RHR and overall fitness level.
How Sleep Stages Affect Heart Rate
The heart rate changes dynamically throughout the night, driven by the shift in dominance between the two branches of the autonomic nervous system. As a person transitions from wakefulness into the lighter stages of non-REM (NREM) sleep, the parasympathetic nervous system begins to take over. This leads to a steady decrease in heart rate and blood pressure.
The heart rate reaches its lowest point during the deepest phase of NREM sleep, known as slow-wave sleep.
During Rapid Eye Movement (REM) sleep, the heart rate becomes more variable and can temporarily increase. This fluctuation is linked to bursts of brain activity and the physiological responses associated with dreaming.
Factors That Influence Baseline Resting Heart Rate
An individual’s baseline RHR, which dictates the lower sleeping range, is established by several long-term factors. Age is one variable, as the heart rate generally decreases from childhood through young adulthood before stabilizing and then slightly increasing in later years. Fitness level is another determinant; people who engage in regular aerobic exercise typically have a lower RHR because their heart is stronger and pumps blood more efficiently.
Underlying health conditions also influence the heart rate baseline. For example, hyperthyroidism can chronically elevate the RHR. Conversely, certain medications, such as beta-blockers, are prescribed to intentionally lower both waking and sleeping heart rates. Chronic conditions like unmanaged stress or underlying cardiovascular issues can also prevent the heart rate from achieving a healthy nocturnal dip.
Signs of Abnormally Low or High Sleep Heart Rate
A persistently slow sleeping heart rate (below 60 bpm) is termed bradycardia, though this is a normal finding for healthy athletes. A sleeping rate consistently above 100 bpm is considered tachycardia. These patterns are concerning if they represent a significant deviation from an individual’s baseline or do not adequately drop during sleep.
When an abnormal rate is accompanied by symptoms like dizziness, fatigue, shortness of breath, or chest pain, a medical evaluation is warranted.
Causes of a persistently high sleeping heart rate include uncontrolled hypertension, rhythm disorders, or excessive stress. A low sleeping heart rate may also signal underlying issues like obstructive sleep apnea, which causes drops in oxygen and disrupts normal heart rhythm.