Lots of runners find utility in using a heart rate training approach to guide workouts. This means that you worry less about your actual running pace and instead, rely on how your body is physiologically responding to your exercise cardiovascularly.
With heart rate training, you wear a heart rate monitor during your workouts and try to keep your heart rate within certain zones, depending on the intended goal of the workout.
There is plenty of research supporting the effectiveness of heart rate training and although monitoring your heart rate during exercise can be helpful, there are other heart rate-related variables and metrics that can also provide insight into your training and physiological readiness to train, such as your sleeping heart rate among others.
Monitoring your resting heart rate can help you get a sense of how well you are recovering after workouts and your heart rate recovery can give you an idea of your aerobic conditioning level and overall health of your heart.
Another helpful heart-related biometric to track can be your average sleeping heart rate. But, what is a normal sleeping heart rate? What’s the difference between resting heart rate vs sleeping heart rate?
In this article, we will discuss what a normal sleeping heart rate is and factors that affect your average heart rate while sleeping.
We will cover:
- What’s A Normal Sleeping Heart Rate?
- Sleeping Heart Rate vs Resting Heart Rate
- How to Decrease Your Average Sleeping Heart Rate
Let’s jump in.
What’s A Normal Sleeping Heart Rate?
Your sleeping heart rate is the number of times your heart beats per minute, on average, while you sleep.
According to the Sleep Foundation, a normal sleeping heart rate for most adults is somewhere between 40 and 50 beats per minute (bpm).Another research study found that the average heart rate during sleep of 10 female subjects was 65 bpm, 63 bpm, and 67 bpm, depending on training status.
Heart rate while sleeping varied by about 8 beats per minute between individuals.
However, as with heart rate during exercise and average resting heart rate, there are several factors that can ultimately affect your own average heart rate while sleeping.
Individual variability in heart rate while sleeping is due to factors such as age, sex, genetics, body size, fitness level, medications, hydration status, stress, and overall health.
Let’s examine how each of these factors can affect your average sleeping heart rate.
Maximum heart rate declines rather linearly with age, and your heart rate while sleeping also tends to decrease throughout the lifespan.
Biological males usually have slightly lower average heart rates while sleeping than biological females.
This is mainly due to the fact that men typically have a larger heart size, which means that the heart muscle is stronger and has larger chambers (ventricles).
Therefore, the heart is able to pump more blood per beat, reflective of a higher stroke volume.
Because more oxygenated blood is circulated per beat of the heart, the heart can beat fewer times per minute while still meeting the oxygenation needs of the body.
Some men even have a heart rate in the 30s while sleeping.
There is some genetic contribution to your maximum heart rate as well as your resting heart rate and sleeping heart rate.
This may be due to how your particular genes control your autonomic nervous system, which in turn, controls your heart rate.
Although exercise training does little to significantly alter your maximum heart rate, endurance training can decrease your average heart rate while sleeping and average resting heart rate.
This is due to the fact that physiological adaptations occur due to chronic aerobic training that make the heart muscle stronger and more efficient, decreasing the number of times your heart needs to beat per minute.
Consistent aerobic exercise causes other cardiovascular adaptations that also contribute to a lower heart rate while sleeping, including increases in blood plasma volume (which means you have more blood pumped per beat), greater elasticity of your blood vessels to handle more blood volume without increasing blood pressure, and larger ventricle size.
Your muscles also develop more mitochondria, helping them extract and use oxygen more economically, reducing the demand on the heart; this, in turn, decreases heart rate while sleeping.
When you are dehydrated, your heart rate while sleeping will be higher than your normal heart rate while sleeping.
Dehydration causes a decrease in blood plasma volume, the fluid portion of your blood.
This essentially means that you have less blood flowing through your body. Therefore, there is less blood returned to the heart to fill the chambers before ejection.
Thus, stroke volume decreases, meaning the amount of blood pumped per beat is less than usual.
To compensate for this relative decrease, the heart has to beat faster in order to meet the oxygen needs of all of the organs and tissues of the body.
For this reason, dehydration can cause an elevated sleeping heart rate.
Smaller individuals tend to have smaller hearts and a higher sleeping heart rate, though individuals who are overweight or obese may have a higher heart rate while sleeping due to poorer cardiovascular efficiency and a larger amount of body tissue to oxygenate relative to the size of the heart.
Certain medications either stimulate or depress the heart rate, potentially altering your average heart rate while sleeping.
Examples include beta blockers, other hypertensive medications, certain antihistamines, stimulants, among others.
Acute and chronic stress can increase your average heart rate while sleeping.
Stress triggers the sympathetic nervous system, which has a stimulatory effect on heart rate.
Any sort of physical stress—injury, illness, overtraining from exercise, etc.—or psychosocial stress—work, financial, anxiety, etc.—can contribute to an increased average heart rate while sleeping.
Some medical conditions, such as heart disease, hypertension, sleep apnea, diabetes, anxiety, and pregnancy may affect your normal sleeping heart rate.
Sleeping Heart Rate vs Resting Heart Rate
Average sleeping heart rate is the mean of your heart rate while you are sleeping. Your heart rate will change somewhat as your sleep based on the sleep stage you are in and your circadian rhythms.
The heart rate drops in the first stage of sleep from your resting heart rate to the beginnings of your sleeping heart rate.
Your heart rate while sleeping is lowest in the deep sleep phase.
Interestingly, during rapid eye movement (REM) sleep, your heart rate may increase up to a rate that’s similar to your resting heart rate or heart rate while awake.
Your resting heart rate is your lowest heart rate during waking hours. This is typically first thing in the morning because when you are lying down and in a calm and relaxed state, your muscles and other tissues require significantly less blood and oxygen than when you are exercising or moving.
Plus, if you are a caffeine drinker, you won’t have had your morning jolt of caffeine that may otherwise increase your “resting heart rate” when you are sitting calmly later in the day.
In general, your heart rate while sleeping is lower than your resting heart rate because your autonomic nervous system is primarily under parasympathetic control during sleep (“rest and digest” nervous system), which slows your heart rate.
Once you are awake, there are more factors that can “turn on” your sympathetic system and lead to slight increases in your heart rate.
However, your resting heart rate is still much lower than your heart rate while moving around or exercising.
According to the American Heart Association, the normal resting heart rate for adults is typically between 60 and 100 beats per minute, although it tends to be lower in fit individuals and trained athletes due to physiological adaptations from consistent training.
This is higher than the sleeping heart rate of 40-50 bpm.
How to Decrease Your Average Sleeping Heart Rate
While it may not be possible to get your heart rate in the 30s while sleeping, there are several things you can do to potentially lower your normal sleeping heart rate:
- Decrease stress through exercise, meditation, breathwork, etc.
- Limit caffeine and use of stimulants, such as nicotine, and alcoholic drinks, especially within six hours before bed.
- Follow a consistent sleep routine, practicing good sleep hygiene.
- Work out consistently, but without overtraining.
- Stay well hydrated and eat a healthy, low-sodium, low-sugar diet.
- Work with your doctor to manage health conditions.
A good starting place is to wear a sleep tracker such as Bellabeat Ivy Health Tracker, which can monitor your heart rate 24/7 and provide detailed insight into your heart rate while sleeping, heart rate variability, and physical readiness and health.
For more information on your resting heart rate, check out our guide: What’s A Good Resting Heart Rate? Average HR By Age And Sex.