One of the most fundamental — and frequently tested — skills in PALS is recognizing when a child's vital signs fall outside normal limits for their age. Unlike adults, where a single set of normal ranges applies, pediatric normal values shift significantly across age groups. A heart rate of 130 is normal in an infant and concerning in a 10-year-old. This guide gives you the reference values you need, explains why they change with age, and shows you how the PALS exam tests this knowledge.
Normal Heart Rate by Age
Heart rate decreases as children grow. Infants have the highest resting heart rates because their cardiac output is heavily rate-dependent — they can't significantly increase stroke volume the way older children and adults can. The PALS exam will present a heart rate and ask you to classify it as normal, tachycardic, or bradycardic for a given age.
| Age Group | Normal HR (bpm) | Bradycardia Threshold |
|---|---|---|
| Neonate (0–28 days) | 100–205 | < 100 |
| Infant (1–12 months) | 100–190 | < 100 |
| Toddler (1–2 years) | 98–140 | < 60 with poor perfusion (PALS intervention threshold) |
| Preschool (3–5 years) | 80–120 | < 60 with poor perfusion |
| School age (6–11 years) | 75–118 | < 60 with poor perfusion |
| Adolescent (12–15 years) | 60–100 | < 60 with poor perfusion |
The key PALS threshold
The AHA PALS intervention threshold for bradycardia is HR < 60 bpm with signs of poor perfusion — regardless of age beyond infancy. At this threshold, CPR is indicated even if the child still has a pulse. This is one of the most commonly tested distinctions on the exam.
Normal Respiratory Rate by Age
Like heart rate, respiratory rate is highest in newborns and decreases with age. Recognizing tachypnea (too fast) is a primary skill in the PALS systematic assessment — it's often the earliest sign of respiratory distress or compensated shock.
| Age Group | Normal RR (breaths/min) | Tachypnea Threshold |
|---|---|---|
| Infant (< 1 year) | 30–60 | > 60 |
| Toddler (1–3 years) | 24–40 | > 40 |
| Preschool (4–5 years) | 22–34 | > 34 |
| School age (6–11 years) | 18–30 | > 30 |
| Adolescent (12–15 years) | 12–20 | > 20 |
Normal Blood Pressure by Age
Blood pressure rises progressively through childhood. Recognizing hypotension is critical for shock identification — but so is recognizing that normal BP does not rule out shock. Children can maintain a normal blood pressure well into decompensated shock through vasoconstriction. By the time hypotension appears, the child is already critically ill.
| Age Group | Systolic BP (mmHg) | Hypotension Threshold (5th percentile) |
|---|---|---|
| Term neonate (0–28 days) | 67–84 | < 60 |
| Infant (1–12 months) | 72–104 | < 70 |
| Toddler / Preschool (1–5 years) | 86–106 | < 70 + (age in years × 2) |
| School age (6–11 years) | 97–115 | < 70 + (age in years × 2) |
| Adolescent (12–15 years) | 112–128 | < 90 |
The formula the exam tests
For children 1–10 years, the AHA uses a quick formula for the lower limit of acceptable systolic BP: 70 + (age in years × 2). For a 4-year-old, that's 70 + 8 = 78 mmHg. Below this threshold is considered hypotension. The exam will give you a patient age and BP and ask whether the value represents hypotension.
Normal Weight Estimates by Age (for Drug Dosing)
Because all PALS drug doses are weight-based, estimating weight quickly during a resuscitation is a critical skill. The Broselow tape is the standard tool used in clinical settings, but for the written exam, you'll need to know how to calculate or estimate weight from a description.
| Age | Estimated Weight | Quick Formula |
|---|---|---|
| Term newborn | ~3–3.5 kg | — |
| 6 months | ~7 kg | — |
| 12 months | ~10 kg | — |
| 1–10 years | Varies | (Age in years + 4) × 2 = weight in kg |
For example, a 6-year-old: (6 + 4) × 2 = 20 kg. This estimate is close enough for quick clinical use and for working through scenario-based drug dosing questions on the exam.
How Vital Signs Connect to PALS Assessment Categories
On the PALS exam, you won't just be asked to identify an abnormal vital sign in isolation — you'll be asked to interpret a set of vital signs together and classify the clinical problem. Here's how abnormal vitals map to PALS categories:
Tachycardia + Tachypnea + Normal BP
Classic early (compensated) shock presentation. The body is compensating through increased heart and respiratory rate. BP is maintained. Immediate fluid resuscitation is indicated.
Tachycardia + Tachypnea + Hypotension
Decompensated shock. The child can no longer maintain blood pressure through compensation. This is a pre-arrest state requiring immediate aggressive intervention.
Tachypnea + Increased Work of Breathing + Normal SpO₂
Respiratory distress (compensated). The child is working hard to maintain oxygenation. Supplemental oxygen and close monitoring are required. If untreated, can progress to respiratory failure.
Bradycardia + Poor Perfusion Signs
Pre-arrest bradycardia. In the PALS algorithm, a heart rate below 60 bpm with poor perfusion triggers CPR initiation even with a pulse present. This is one of the most exam-tested thresholds in all of PALS.
Tips for Memorizing Pediatric Vital Sign Ranges
Memorizing exact ranges for every age group isn't as useful as understanding the patterns. A few memory anchors:
- Heart rate decreases with age. Newborns fast, adolescents slow.
- Respiratory rate decreases with age. Same direction as heart rate.
- Blood pressure increases with age. Opposite direction — kids get bigger and their vessels handle more pressure.
- The 60 bpm threshold for CPR-indicated bradycardia applies across ages beyond early infancy.
- The 70 + (age × 2) formula is your quick reference for hypotension in kids 1–10.
Focus your practice on scenario-based questions that give you an age, a set of vital signs, and ask you to classify the clinical problem. That's how the exam tests this material — not by asking you to recite a table.