Normal Respiratory Rate in Children
Normal respiratory rates in children decline steadily with age, from a median of approximately 44 breaths per minute at birth to 26 breaths per minute by age 2 years, continuing to decrease through adolescence.
Age-Specific Normal Ranges
The most robust evidence comes from a systematic review analyzing 143,346 children 1, which established evidence-based centile charts. Here are the key reference values:
Infants and Toddlers (Birth to 2 Years)
- Birth: Median 44 breaths/min (awake), 41 breaths/min (asleep) 1, 2
- 1 month: Approximately 40-43 breaths/min
- 6 months: Approximately 35-38 breaths/min
- 1 year: Approximately 30-33 breaths/min
- 2 years: Median 26 breaths/min 1
The steepest decline in respiratory rate occurs during the first 2 years of life 1.
Preschool and School-Age Children
- 3 years: Median approximately 25 breaths/min (awake), 22 breaths/min (asleep) 2
- 4-6 years: Approximately 22-24 breaths/min 3
- 6-12 years: Approximately 18-22 breaths/min 3
Adolescents (12-18 Years)
- 12-18 years: Continues gradual decline into adult ranges (approximately 12-20 breaths/min) 1
Critical Clinical Considerations
Measurement Technique Matters
Always count respiratory rate for a full 60 seconds 4. This has been demonstrated as the most accurate method. Shorter observation periods introduce significant error 5.
Sleep State Significantly Affects Rate in Young Children
Respiratory rates are systematically higher when children are awake versus asleep, particularly in children under 3 years 2. The difference can be substantial:
- At birth: 59.3 awake vs. 41.4 asleep
- At 3 years: 25.4 awake vs. 22.0 asleep
Failing to account for sleep state in infants and toddlers is a common pitfall that leads to misinterpretation of vital signs 2.
Clinical Thresholds for Tachypnea
When evaluating for pneumonia or respiratory illness, specific tachypnea definitions have been validated 4:
- **<6 months**: >59 breaths/min
- 6-11 months: >52 breaths/min
- 1-2 years: >42 breaths/min
- Bronchiolitis (any age <2 years): ≥70 breaths/min indicates increased risk of severe disease 5
Measurement Method Affects Results
Respiratory rates measured with a stethoscope are systematically 2-3 breaths/min higher than those obtained by observation alone 6. Modern optical sensors provide non-invasive alternatives that avoid observer effect 2.
Important Caveats
Traditional reference ranges published in resuscitation guidelines (like APLS) frequently exceed the 99th centile or fall below the 1st centile when compared to evidence-based data 1, 7. The systematic review data 1 should supersede older published ranges that were not evidence-based.
The greatest variability and dispersion in respiratory rate values occurs in the first few months of life 6, making precise assessment particularly important during this period.
A normal respiratory rate has high negative predictive value (97%) for ruling out pneumonia in febrile children 4, making it a valuable screening tool when within normal limits.