What Is a Normal Heart Rate for a Sleeping Baby?

What Is a Normal Heart Rate for a Sleeping Baby
Normal heart rates for a sleeping baby range between 65-100 beats per minute, depending on their age. Heart rate is slower when they are asleep

Normal heart rates for a sleeping baby range between 65-100 beats per minute, depending on their age.

Similar to adults, a baby’s heart rate varies depending on their activities, often slower during sleep and faster when awake. However, if you find that the baby's heart rate is lower during the day and they are looking lethargic, it is important to contact your pediatrician right away.

A baby’s heart rate is typically much higher than that of an adult. As babies grow, their heart rate slows. You can check your baby's heart rate by pressing your fingers gently on the wrist, the backside of the elbow, or the side of the neck. You can also hold your palm over your baby’s beating heart. Count beats for 15 seconds, then multiply by 4. This gives your baby's heart rate in beats per minute.

Table: Normal heart rates of a baby when asleep and awake
Age Sleeping heart rate (in beats per minute) Awake heart rate (in beats per minute)
Newborn 90 to 160 100 to 205
Infant 90 to 160 100 to 180
1 to 2 years 80 to 120 98 to 140
3 to 5 years 65 to 100 80 to 120

What are different types of abnormal heart rates?

Sometimes, your baby may develop abnormal heart rates or heart rhythms. These include the following:

  • Tachycardia (fast heart rate)
    • Supraventricular tachycardia (SVT)
    • Ventricular tachycardia (VT)
  • Bradycardia (slowed heart rate)
    • Sinus bradycardia
    • Heart block

Infants with abnormal heart rhythms may seem fussy, pale, and have low energy levels and problems with feeding.

Supraventricular tachycardia

SVT, also referred to as atrial tachycardia in some cases, is the most common abnormal heart rhythm found in children, including babies. It affects as many as 1 in 250 children. 

SVT occurs when abnormal electrical signals originate in the upper chambers (atria) of the heart, which raises heart rate suddenly and lasts several seconds, minutes, or hours. Different types and causes of SVT include the following:

If your baby is affected by atrial flutter and atrial fibrillation, they are at increased risk of developing blood clots. Much less common than other types of SVT, these may also be associated with congenital heart abnormalities or heart muscle disorders such as cardiomyopathy.

Ventricular tachycardia

Like SVT, VT also causes fast heartbeats. However, the problem originates in the lower chambers (ventricles), not the atria. VT is rare but increases the risk of cardiac arrest in babies, which can be life-threatening.

Bradycardia

  • Sinus bradycardia. Seen more often in premature infants and may occur due to a drop in body temperature or breathing problems.
  • Heart block. Caused by an obstruction in the passing of electrical signals from the atria to the ventricles.

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How are abnormal heart rates or heart rhythms treated in babies?

Your pediatrician may refer your baby to a pediatric cardiologist, who will evaluate your baby’s heart rate or rhythm abnormalities and recommend treatment accordingly. Treatment options may include:

  • Anti-arrhythmic drugs: Medications to correct the heart rhythm
  • Pacemakers: Small implanted device that sends electrical signals to speed up the heartbeat if it has slowed
  • Defibrillators: Small implanted device that sends electrical signals to slow down the heart if it is fast and also corrects abnormal heart rhythm
  • Catheter ablation: Heating or freezing of the defective area by passing a catheter into the heart through a vein in the leg or neck
  • Surgery: Removal of the heart tissue responsible for the abnormal heartbeats or heart rhythm
References
Image Source: iStock Images

"Fast, Slow, and Irregular Heartbeats (Arrhythmia)." <https://www.healthychildren.org/English/health-issues/conditions/heart/Pages/Irregular-Heartbeat-Arrhythmia.aspx>.

"Arrhythmia (Abnormal Heartbeat)." <https://kidshealth.org/en/parents/arrhythmias.html>.