Baby Heart Rate and Respiratory Rate: Normal Ranges by Age

What counts as a normal heart rate or breathing rate for a baby? The largest systematic review ever conducted on pediatric vital signs answers this precisely, with data from over 140,000 children. Here are the reference ranges by age, in clear tables, and what actually explains the wide variation parents often notice.

What science says: the largest review of pediatric vital signs ever conducted

Heart rate and respiratory rate are measured routinely in every pediatric visit, yet for decades the "normal ranges" used in charts and textbooks were not built from solid evidence. A landmark systematic review changed that.

Fleming and colleagues combined data from 69 studies covering 143,346 children for heart rate and 3,881 children for respiratory rate, from birth to 18 years of age (Fleming et al., 201162226-X)). The review produced new, evidence-based centile charts and found that several widely used reference ranges did not match the real population data, particularly at the youngest ages.

Normal heart rate by age: the reference table

Heart rate rises sharply after birth, peaks around one month, then falls steadily through the first two years as the cardiovascular system matures. A baby's resting heart rate says very little in isolation; it only means something read against the right age bracket.

Centile data adapted from [Fleming et al., 2011](https://doi.org/10.1016/S0140-6736(10)62226-X), The Lancet.

Normal respiratory rate by age: the reference table

Respiratory rate falls even more sharply than heart rate over the same period. A newborn breathes roughly twice as fast as a two-year-old, and this decline is steepest during exactly the months when parents worry most about "fast breathing."

Centile data adapted from [Fleming et al., 2011](https://doi.org/10.1016/S0140-6736(10)62226-X), The Lancet.

Why these values vary so much

A baby's heart rate and breathing rate are not fixed numbers; they are a range that shifts constantly with the baby's state. Quiet sleep, active sleep, wakefulness, feeding, and crying each pull heart rate and respiratory rate in different directions, sometimes by 20 to 30 beats or breaths per minute within the same hour.

This is exactly why the systematic review reports ranges, not single figures, at every age: a heart rate of 150 bpm can be entirely normal for an awake, feeding 2-month-old, while the same number would sit at the upper edge of normal for a 2-year-old in quiet sleep. Context and age both matter more than any single reading.

When to actually worry

A single elevated or low reading rarely means anything on its own; it needs to be interpreted against the baby's age, state, and how persistent the change is. A pediatrician should be consulted if a baby's breathing or heart rate stays clearly outside the normal range for their age over an extended period, especially alongside other signs like poor feeding, lethargy, unusual color changes, or visible difficulty breathing (marked chest retractions, grunting, flaring nostrils).

Some contact-free monitoring technologies, such as smart mattress pads slipped under the fitted sheet, let parents observe continuous breathing and heart-rate trends throughout the night without any sensor touching the baby's skin. Devices like Mothair use precision accelerometers and pressure sensors to pick up the tiny mattress vibrations created by breathing, and ballistic cardiography, detecting cardiac vibrations transmitted through the mattress, to follow heart rate over time. This kind of continuous, non-invasive tracking can offer a reassuring sense of a baby's usual patterns, but it remains a wellness tool for peace of mind, not a medical diagnostic device, and never replaces a pediatrician's assessment.

Important: Mothair is a wellness tracking device for babies. It is not a medical device under EU Regulation 2017/745 (MDR) and never replaces professional medical care. The information in this article comes from public scientific sources and does not constitute medical advice; consult your pediatrician for any question about your baby's heart rate, breathing, or health.

FAQ

What is a normal heart rate for a newborn?

In newborns, median heart rate is around 127 beats per minute, peaking near 145 bpm at about 1 month of age, then gradually falling to roughly 113 bpm by age 2, according to the largest systematic review ever conducted on the topic (Fleming et al., 201162226-X)).

What is a normal respiratory rate for a baby?

Respiratory rate falls quickly over the first two years of life: from a median of 44 breaths per minute at birth to about 26 breaths per minute by age 2, with the steepest decline occurring in infants under 2.

Why does my baby's heart rate and breathing rate vary so much?

These values reflect the rapid maturation of the cardiorespiratory system during the first year of life. They also vary with the baby's state (quiet sleep, active sleep, awake, crying), which explains the width of the normal ranges reported in studies.

Can a baby monitor track these values without waking my baby?

Some contact-free monitoring technologies, like smart mattress pads, let parents observe continuous breathing and heart-rate trends during sleep without any sensor touching the skin. This kind of tracking remains a wellness and peace-of-mind tool, never a medical diagnostic device.

Key Takeaways

• The largest systematic review of pediatric vital signs (143,346 children) established the first truly evidence-based heart rate and respiratory rate ranges by age (Fleming et al., 201162226-X)).
• Median heart rate peaks around 145 bpm near 1 month of age, then falls to about 113 bpm by age 2.
• Median respiratory rate falls from 44 to 26 breaths per minute over the same two years, with the steepest decline in the first months.
• A baby's state (sleep, wake, feeding, crying) explains much of the variation seen within a single normal range.
• Persistent readings outside the normal range, especially with other warning signs, warrant a pediatrician's assessment; contact-free trend tracking is a wellness complement, never a replacement, for medical care.

Related reading: for more on how home monitoring technology tracks these signals in the context of sleep safety, see our guide on SIDS prevention: what research says.