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Why is Your Baby’s Heart Beating Fast While Sleeping? Exploring the Causes and Solutions

Possible Reasons for a Baby’s Heart Beating Fast While Sleeping

There can be several reasons why a baby’s heart beats fast while sleeping. One common cause is the natural development of their cardiovascular system. In newborns and young infants, it is normal for the heart rate to be higher during sleep compared to adults. This is because their hearts are smaller and need to work harder to pump blood efficiently. As the baby grows, their heart rate gradually decreases and becomes more similar to that of an adult.

Another possible reason for a fast heartbeat during sleep is physical activity or stimulation before bedtime. If a baby has been active or excited prior to sleep, their heart rate may take some time to calm down and return to normal. Additionally, certain medications or medical conditions can also affect a baby’s heart rate during sleep.

Factors that can contribute to a fast heartbeat in babies during sleep:

  • Natural development of the cardiovascular system
  • Physical activity or stimulation before bedtime
  • Medications or medical conditions


If your baby’s heart rate remains consistently high during sleep or if you have any concerns about their health, it is always best to consult with a pediatrician for further evaluation and guidance.

Is it Normal for a Baby’s Heart Rate to Increase During Sleep?

Yes, it is generally considered normal for a baby’s heart rate to increase during sleep, especially in newborns and young infants. The autonomic nervous system plays a role in regulating heart rate, among other bodily functions. During REM (rapid eye movement) sleep, which is the phase associated with active dreaming, the autonomic nervous system becomes more active and can cause temporary increases in heart rate.


Additionally, babies have smaller hearts and blood vessels compared to adults, so their hearts need to work harder to pump blood efficiently. This can result in a higher resting heart rate during sleep. As the baby grows and their cardiovascular system matures, their heart rate gradually decreases and becomes more similar to that of an adult.

Factors contributing to a normal increase in a baby’s heart rate during sleep:

  • The autonomic nervous system becoming more active during REM sleep
  • Babies having smaller hearts and blood vessels
  • The gradual decrease in heart rate as the baby’s cardiovascular system matures

How to Monitor Your Baby’s Heart Rate While They Are Sleeping

Monitoring your baby’s heart rate while they are sleeping can provide valuable information about their health and well-being. There are several methods you can use to monitor your baby’s heart rate at home:

Using a Baby Monitor with Heart Rate Monitoring Feature:

Some baby monitors come with built-in features that allow you to track your baby’s heart rate. These monitors usually include a sensor pad that goes under the mattress or a wearable device that attaches to the baby’s body. The monitor then displays the real-time heart rate on its parent unit or through a smartphone app.

Using a Pulse Oximeter:

A pulse oximeter is a small device that measures oxygen saturation levels and heart rate by clipping onto the baby’s finger or toe. It uses light beams to detect changes in blood flow and provides accurate readings within seconds. However, it is important to note that pulse oximeters may not be suitable for continuous monitoring during sleep due to their potential interference with circulation.


It is essential to consult with a healthcare professional before using any monitoring devices and to follow their instructions for accurate and safe usage.

Potential Health Concerns Associated with a Baby’s Fast Heartbeat During Sleep

1. Premature Ventricular Contractions (PVCs)

One potential health concern associated with a baby’s fast heartbeat during sleep is the occurrence of premature ventricular contractions (PVCs). PVCs are extra, abnormal heartbeats that originate in the ventricles of the heart. While they can be benign and go unnoticed in some cases, frequent PVCs may indicate an underlying heart condition that requires medical attention.

2. Supraventricular Tachycardia (SVT)

Another possible health concern is supraventricular tachycardia (SVT), which is characterized by a rapid heart rate originating above the ventricles. SVT can cause symptoms such as palpitations, dizziness, and shortness of breath. It is important to consult a healthcare professional if you suspect your baby may be experiencing SVT during sleep.

Can a Baby’s Heart Rate be Affected by Their Sleep Position or Environment?

A baby’s sleep position and environment can indeed have an impact on their heart rate during sleep. Here are some factors to consider:

Sleep Position

The position in which a baby sleeps can affect their heart rate. For example, placing a baby on their back to sleep has been recommended by healthcare professionals as it reduces the risk of sudden infant death syndrome (SIDS). However, some babies may experience brief episodes of increased heart rate when sleeping on their backs due to positional changes or reflux. Monitoring your baby’s heart rate while they sleep in different positions can help determine if there is any correlation.

Noise and Light Levels

The sleep environment, including noise and light levels, can also influence a baby’s heart rate. Loud noises or bright lights may cause temporary increases in heart rate due to the startle reflex. Creating a calm and quiet sleep environment can help promote a more stable heart rate during sleep.

Steps to Take If You Notice Your Baby’s Heart Beating Unusually Fast During Sleep

If you notice your baby’s heart beating unusually fast during sleep, it is important to take the following steps:

1. Monitor the Heart Rate

Use a baby monitor equipped with a heart rate monitor or consult with your pediatrician about using an at-home pulse oximeter to accurately measure your baby’s heart rate during sleep. This will provide objective data for further evaluation.

2. Document Episodes

Keep a record of when you observe your baby’s fast heartbeat during sleep, noting any accompanying symptoms or triggers. This information will be helpful for healthcare professionals in diagnosing and treating any potential underlying conditions.

3. Consult a Healthcare Professional

If you have concerns about your baby’s fast heartbeat during sleep, it is crucial to consult with a healthcare professional such as your pediatrician or a pediatric cardiologist. They can conduct further evaluations, order tests if necessary, and provide appropriate guidance based on their expertise.

Natural Remedies and Techniques to Help Regulate a Baby’s Heart Rate During Sleep

While it is important to consult with healthcare professionals for proper diagnosis and treatment, there are some natural remedies and techniques that may help regulate a baby’s heart rate during sleep:

1. Establishing a Consistent Bedtime Routine

  • Create a soothing bedtime routine that includes activities like gentle massage, reading a book, or singing lullabies. This can help promote relaxation and a more stable heart rate during sleep.

2. Maintaining Optimal Sleep Environment

  • Ensure the sleep environment is comfortable, quiet, and free from excessive stimulation. Use blackout curtains to create a dark room and consider using white noise machines to drown out any disruptive sounds.

3. Encouraging Healthy Sleep Habits

  • Promote healthy sleep habits by establishing regular nap times and ensuring your baby gets enough daytime sleep. Adequate rest can contribute to overall heart health and regulate heart rate during sleep.

Differences in Heart Rate Patterns Between Newborns and Older Infants During Sleep

The heart rate patterns of newborns and older infants during sleep can vary due to developmental changes. Here are some key differences:

Newborns (0-3 months)

Newborns typically have higher resting heart rates compared to older infants. Their heart rates may range from 100 to 160 beats per minute during sleep. Additionally, newborns may experience periodic breathing patterns where their heart rate temporarily increases or decreases in a cyclical manner.

Older Infants (4-12 months)

As infants grow older, their resting heart rates tend to decrease gradually. The average heart rate for older infants during sleep ranges from 80 to 120 beats per minute. They may also exhibit more stable heart rate patterns with fewer fluctuations compared to newborns.

Medical Conditions That Can Cause a Baby’s Heart to Beat Faster While Sleeping

A baby’s fast heartbeat during sleep can be attributed to various medical conditions. Some potential causes include:

1. Fever

When a baby has a fever, their heart rate may increase as the body’s response to fighting off an infection. Monitoring your baby’s temperature and seeking appropriate medical care is important in such cases.

2. Respiratory Infections

Infections affecting the respiratory system, such as bronchiolitis or pneumonia, can lead to increased heart rate during sleep. It is essential to consult with a healthcare professional for proper diagnosis and treatment.

3. Congenital Heart Defects

Babies born with congenital heart defects may experience faster heart rates during sleep due to the compromised function of their heart. These conditions require specialized medical attention and monitoring.

The Role of the Autonomic Nervous System in Regulating a Baby’s Heart Rate During Sleep

The autonomic nervous system plays a crucial role in regulating a baby’s heart rate during sleep. It consists of two main branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).

Sympathetic Nervous System (SNS)

The SNS is responsible for increasing heart rate and preparing the body for action or stress responses. During sleep, it can be activated by factors like dreams, discomfort, or environmental disturbances, leading to temporary increases in heart rate.

Parasympathetic Nervous System (PNS)

The PNS helps regulate heart rate by promoting relaxation and slowing down the heartbeat. It becomes more active during periods of restful sleep, contributing to a lower and more stable heart rate.

In conclusion, it is not uncommon for a baby’s heart to beat fast while sleeping. This natural occurrence is typically caused by the body’s adjustment to rest and should not be a cause for concern.

Why does my baby’s heart beat faster when sleeping?

A newborn baby typically has a resting heart rate of 90 to 160 beats per minute while sleeping and 100 to 190 beats per minute when awake, and even up to 205 beats per minute when crying. This is because their growing bodies require efficient circulation. Additionally, babies lose body heat more quickly than older individuals.

Should I be worried if my baby’s heart is beating fast?

When the heart beats at a rapid rate, it pumps a lower volume of blood with each contraction. This can lead to heart failure in the fetus. The most prevalent type of this condition is known as supraventricular tachycardia (SVT), where the heart rate can exceed 200 beats per minute.

Why does my baby’s heart feel like it’s racing?

If a child is feeling nervous or scared, has a fever, consumed too much caffeine, taken a stimulant medication, engaged in physical activity, or has a medical condition like low blood sugar or a low blood count, they might notice that their heart is beating fast.

What causes SIDS in babies?

Although the exact cause of SIDS is not known, experts in the medical field speculate that it may be linked to issues with a baby’s ability to wake up from sleep, detect low oxygen levels, or deal with an accumulation of carbon dioxide in the bloodstream. When infants sleep on their stomach, they may breathe in their own exhaled carbon dioxide again.

How do I know if my baby’s heart rate is too fast?

The average heart rate for a developing fetus is usually between 120 and 160 beats per minute. A heart rate that exceeds 200 beats per minute is considered unusually fast.

Does high fetal heart rate mean distress?

The typical indications of fetal distress include fluctuations in the fetal heart rate (either lower or higher than the normal rate) and reduced fetal movement for a prolonged period of time.

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