Heart Rate During Sleep

Table of Contents

Think of sleep as a housekeeping mechanism for your body. Without sleep, the human body cannot form pathways in your brain that let you concentrate, learn new things, and create memories. Sleep is essential for survival and cognitive function. A recent study suggests that without sleep toxins build up in your brain while you are awake increasing the risk of health conditions such as high blood pressure, cardiovascular disease, diabetes, depression, and obesity.

There are a few ways you can monitor your sleep to analyze its quality. Different technologies use sounds, movements, and pulse analyses. Heart rate during sleep is changing and depends on many factors and stages of sleep, therefore, pulse monitoring is considered the most accurate method to monitor sleep.

Resting Heart Rate

Heart rate (HR) is the number of times your heart beats in a minute. Both resting (when you are staying still with no particular stimuli) and normal (when you are at your habitual activity level) HR are individual and depend on the age and general physique. A resting heart rate (RHR) between 60 and 100 beats per minute is considered normal.

One’s resting pulse can provide valuable information about their health. Most of the time, a low resting heart rate (e.g. around 60 beats per minute) can be an indicator of cardiovascular fitness, whereas a high RHR can be an adverse sign. If your resting pulse is below 40 or above 120, it is advised to visit a general practitioner.  

Infographic depicting normal resting heart rate by age

Heart rate increases when a person is active or exercising. Heart.org suggests that the maximum heart rate is about 220 minus your age. Exercise heart rate is usually about 50-70% of maximum heart rate, however, it can be up to 85% of maximum rate during vigorous physical activity.  Maximum heart rate declines with age. The target heart rate for exercise also declines as we get older.

Heart rate variability (HRV) is a health marker that measures how uneven your heartbeat is and reflects the current state of your nervous system. Healthcare professionals use HRV to analyze patient variability when treating chronic illnesses, for instance: diabetes, renal failure, neurological and psychiatric conditions, sleep disorders as well as rehabilitation from alcohol and drug addiction. Understanding your heart rate and HRV during sleep can help you adjust your routine for better recovery of both your physical and mental health. 

Heart Rate During Sleep - What’s The Norm

We need to talk about different sleep stages to understand what a good heart rate and heart rate variability during sleep are. When you are at rest, your body needs less oxygen, which makes your heart pump a lower amount of blood. Heart rate decreases but it does not necessarily mean that your heart rate variability during sleep is going to be low. In fact, it will also fluctuate depending on the stage of sleep.

The human body cycles through two phases of sleep approximately 4 to 6 times each night: 

  • rapid eye movement (REM) 
  • non-rapid eye movement (NREM) sleep, which is divided into three stages: light sleep, deeper sleep, and deep non-REM sleep, also known as slow-wave sleep.
Sleep cycle with REM and NREM phases screenshot from Welltory app

[Sleep cycle with REM and NREM phases]

The average time of a cycle is about 90 minutes.  


Heart rate during sleep is called nocturnal heart rate. When we enter light sleep, the heart rate begins to slow and gradually slows to its resting rate. The average sleeping heart rate is at the lower end of the normal RHR range of 60–100 bpm. During deep sleep, the heart rate reaches its lowest levels. When we enter the deeper sleep stages, the resting heart rate can drop by about 20 to 30 percent. Heart rate during REM sleep, on the other hand, may speed up to a rate similar to when you are awake. 


Rapid fluctuations in autonomic activity controlling coronary artery tone, systemic blood pressure, and HR are associated with a dynamic state of consciousness during nighttime. Normal heart rate variability during sleep is typically higher. Nocturnal heart rate is an important metric that helps quantify the efficiency of your cardiovascular system. A 1992 research suggests that HR during sleep may be an even more accurate assessment of heart rate compared with morning resting heart rate.

How Does Heart Rate Change During Sleep?

It is normal for nocturnal heart rate values to be slightly lower even than waking RHR. Your heart rate during sleep can go as low as 40 to 50 beats per minute. The average heart rate falls steadily from the waking stage to deep sleep. During REM, HR increases lightly and presents greater variability than during wakefulness.


The overall pattern of HR and HRV changes is influenced by body circadian temperature, stage of sleep, body movements, and awakenings. 

Heart rate fluctuations during sleep and different sleep stages

[Heart rate fluctuations during sleep and different sleep stages]

When Is a Heart Rate Dangerous During Sleep?

Heart rate can spike during sleep due to the lack of oxygen, which is often brought on by obstructive sleep apnea (OPA). When you experience trouble breathing, your brain recognizes that things aren’t right, and wakes you up to kickstart normal breathing functions again. This causes your heart to beat faster and compromises the quality of your sleep. Sleep apneas may happen many times each night.

Frequent spikes in your heart rate are not healthy in the long turn because they stress the health of your heart. Studies show that OSA may increase the risk of atrial fibrillation with symptoms such as fatigue, shortness of breath, and chest pain. Atrial fibrillation is associated with cardiovascular conditions including stroke and heart failure. It’s also important to note that a person with OPA also wakes up their partner, whose quality of sleep is also affected as a result of the noise.

Obstructive sleep apnea compromises the quality of sleep

A nightmare, night terror, and sleep paralysis can all cause physical symptoms in the body that lead to a racing heart. Diet and certain drinks can have a significant impact on sleep quality, especially when consumed at night. Having sweet treats and drinking alcohol or coffee before bed may cause elevated heart rate during sleep. Being dehydrated can lead to an irregular heartbeat leaving you with a rapid heart rate and breathing and low blood pressure.

Awakening during the night, during any stage of sleep, increases sympathetic activity, elevates heart rate, and blood pressure, and lowers HRV. Reduced HRV in different medical conditions or in healthy subjects is associated with increased cardiovascular risk. If your heart rate does not slow down during sleep at all, it might signal you about serious cardiovascular health issues. Don’t panic if it happens once every now and then but remember that if it happens too often or every night, it might be a good idea to start tracking how well you sleep and visit a doctor.

Quantity or Quality: How can Welltory help with my sleep routine?

The amount of sleep we get is important, but in recent years, the quality of sleep has also been considered very significant. Based on an in-depth analysis of your overnight heart rate patterns and historical sleep data, Welltory’s insights are personalized and packed with information that will steer you toward better recovery. Welltory Pro gives you a detailed sleep analysis that shows how well you slept last night.

Once you sync your tracker or smartwatch with Apple Health, we’ll grab your sleep data from there and send the analysis to your feed. Raw sleep metrics show the raw sleep data from your fitness tracker — your resting heart rate, wake-ups, and total sleep time are all here. This is the data our algorithms use to analyze your sleep.

Using a smartwatch or a fitness tracker with Welltory daily can give you an overview of how you slept and the optimal bedtime recommendations.

Inside the app, you will find a detailed breakdown of your smart sleep metrics. You can see which factors impacted your sleep quality most and learn more about what your body needs for better recovery. Once you know how you’re sleeping, it will be much easier for you to improve it. Maintaining positive habits such as exercising may help strengthen the body’s most vital muscle- the heart.

Welltory Team, 04 Nov. 2022

Andrea Miklos

20 Sept. 2019

The app makes me focused on the signs my body gives, and translates well what I should do to improve. It’s very useful to see how my body reacts to external factors, such as a walk, workout, meditation. It’s great that I can also add the blood pressure measurements, and it’s comforting to see that the 2 tools measure almost the same heartbeats. It would be even better if I could add a note of each day, not just tags but longer information.

Mrs Lonnie Ataya

20 Sept. 2019

This APP is wonderful, it helps me keep track of how my daily habits affect my body and helps me track my stressors. It’s very user friendly and simple to use, I also love how I get advice and tips on ways to help me me improve my physical and mental health. I recommend this APP to anyone who wants to keep track of how their body is doing, I won’t go into all the details but if you’re looking to improve your productivity, physical performance, and help reducing your stress as well as important insights to your overall health then use this App! Thank you Welltory for helping me on my journey of self improvement, the knowledge I’ve gained has helped me so much and I’ll continue with you as long as I can, you’re support is priceless! I can’t recommend this App enough😊

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