Normal Values in Children: Interpreting Heart Rate, Respiratory Rate and Blood Pressure

Why age-specific normal values matter in emergencies

A value that counts as tachycardia in adults may be normal in an infant. A blood pressure that is reassuring in a school-age child may already be abnormal in an adolescent. Anyone providing emergency care to children therefore needs reference ranges stratified by age. Without them, it is easy to miss early warning signs or to overinterpret physiological values.

In children, cardiorespiratory arrest is usually the result of respiratory failure (hypoxia) or circulatory failure (shock) and is rarely a primary cardiac event [2]. This progression can often be detected earlier in the vital signs. Normal values for children are therefore not exam knowledge but a tool for initial assessment.

Normal values in children: overview table according to ERC 2025 / RCUK 2025

The following table is taken from the paediatric emergency table of the compendium. Heart rate and respiratory rate are given as normal ranges. Systolic blood pressure is given as the median, with the lower limit (5th percentile, P5) in brackets [2, 132, 133]. Weight is estimated from age using the APLS formulae [134].

How to read the table

• Heart rate and respiratory rate are given as ranges. The limits are reference values, not sharp dividing lines between "healthy" and "ill".
• Systolic blood pressure: the median describes the typical value for the age group. The P5 marks the lower limit below which a value is to be classified as low.
• Preterm infants: no blood pressure value is given for this group in the table. Neonatal reference values and local standards apply here.
• The table covers children up to 12 years. For older children and adolescents, the current guideline should be consulted.

Heart rate: what is normal in a child?

The question "What heart rate is normal in a child?" depends primarily on age. In newborns and infants up to about six months, the normal range is 110–180/min. It then decreases gradually:

• 100–170/min at one year
• 90–160/min between two and four years
• 70–140/min between five and eight years
• 60–120/min at ten to twelve years [2, 132]

The systematic review by Fleming et al. on heart rate and respiratory rate from birth to 18 years of age provides a key evidence base for age-related reference ranges. It shows a marked decline in both parameters, particularly in the first years of life [136]. At the same time, the ranges of adjacent age groups overlap widely. A single value just outside the range must therefore always be assessed in the clinical context.

In children, circulatory compensation occurs mainly through heart rate. Tachycardia is therefore often the first measurable sign of impending shock. Bradycardia in a critically ill child, by contrast, is a warning sign. In the ERC algorithm, bradycardia with poor perfusion is managed in the non-shockable rhythm arm, i.e. treated as cardiac arrest [2].

Respiratory rate: an early indicator, often underestimated

Respiratory rate also decreases with age:

• 25–60/min in preterm infants, newborns and infants up to six months
• 20–50/min at one year
• 18–40/min between two and four years
• 17–30/min between five and eight years
• 14–25/min at ten to twelve years [2, 132]

Respiratory rate is more difficult to measure in an emergency than heart rate. Counting over a full minute in a calm child is the most reliable method. Tachypnoea may be respiratory in origin but may also have metabolic causes, such as respiratory compensation for acidosis in shock. A falling respiratory rate with increasing exhaustion is not a sign of improvement and may herald impending respiratory arrest. Assessment in conjunction with work of breathing, level of consciousness and oxygen saturation is therefore essential.

The compendium table additionally includes tidal volume (VT) as a guide for ventilation, calculated at 7 ml/kg. For a one-year-old child with an estimated weight of 10 kg, this gives approximately 70 ml.

Normal blood pressure values in children: median and 5th percentile

For normal blood pressure values in children, the table distinguishes between the median and the lower limit (P5) [2, 132]:

• Newborns and infants up to 6 months: median 75 mmHg, P5 50 mmHg
• 1 year: median 95 mmHg, P5 70 mmHg
• 2–4 years: median 98 mmHg, P5 73 mmHg
• 5–8 years: median 100 mmHg, P5 75 mmHg
• 10–12 years: median 110 mmHg, P5 80 mmHg

A systolic value below the P5 is to be regarded as hypotension. Conversely, a normal blood pressure does not exclude shock. Children often maintain their blood pressure for a long time through tachycardia and peripheral vasoconstriction. A fall in blood pressure therefore tends to indicate advanced decompensation. The following are equally important for assessment:

• Capillary refill time
• Skin colour and skin temperature
• Pulse quality (central and peripheral)
• Level of consciousness
• Urine output, where assessable

An age-appropriate cuff size is required for measurement. Cuffs that are too small or too large distort the result. Oscillometric measurements may be unreliable in the presence of agitation, cold or centralisation of the circulation.

Interpretation in emergencies

Trend rather than single value

Repeated measurements are more informative than a single value. A heart rate that falls during treatment and a respiratory rate that normalises while work of breathing decreases indicate a response. If, however, values fall without clinical improvement, exhaustion should be considered.

Physiological confounders

Fever, pain, anxiety, crying and physical activity increase heart rate and respiratory rate, sometimes well above the normal range. Values should therefore be obtained, wherever possible, in a settled child, for example on a caregiver's lap. Tachycardia that persists despite analgesia, antipyretic treatment and reassurance deserves particular attention.

Structured assessment

Incorporating vital signs into a structured ABCDE approach has proven useful. Normal values help to describe findings objectively and to communicate them consistently within the team. However, they do not replace the overall clinical impression.

Implications for treatment

In suspected hypovolaemia, ERC 2025 recommends a fluid bolus of 10 ml/kg of balanced crystalloid solution, repeatable after reassessment. In cardiogenic shock, a more cautious approach is indicated, e.g. with 5 ml/kg [2]. Vital signs should be reassessed after each bolus. Normal values serve as a target corridor rather than a rigid target.

Transition to resuscitation

If a child is unresponsive and not breathing normally, ERC 2025 recommends five initial rescue breaths, followed by chest compressions and ventilation at a ratio of 15 : 2 with a compression rate of 100–120/min [2]. Drug doses, tracheal tube sizes and defibrillation energies should be taken from the paediatric emergency table or the current guideline.

Weight as a common reference parameter

In the table, normal values are linked to an estimated weight. They are based on the APLS formulae [134]:

• Infants: 0.5 × months + 4 kg
• 1–5 years: 2 × age + 8 kg
• 6–12 years: 3 × age + 7 kg

The validity of such age-based formulae has been examined in validation studies [135]. Nevertheless, they remain estimates. If the actual weight is known, it takes precedence. Sources include information from the parents, the child health record (e.g. the Austrian Mutter-Kind-Pass) or a length-based tape. From 13 years of age or from puberty onwards, the actual weight should be ascertained.

Limitations of normal values

• The reference ranges describe healthy children and apply to typical patients. In children with congenital heart disease, chronic lung disease, neuromuscular disorders or on long-term medication, individual baseline values may differ considerably.
• In preterm infants and newborns, neonatal reference values and local standards should be taken into account.
• The evidence on percentile limits is limited. Different guidelines and tables use partly different ranges [132, 133, 136].
• Local protocols (SOPs, care pathways) take precedence.

The complete paediatric emergency table with vital signs, airway sizes and doses is included in the "Notfall & Narkose" web app and in the A6-format pocket book.

References

• [2] Djakow J, Turner NM, Skellett S et al. European Resuscitation Council Guidelines 2025 Paediatric Life Support. Resuscitation 2025;215 Suppl 1:110767.
• [132] Resuscitation Council UK. Paediatric advanced life support algorithm – 2025 Resuscitation Guidelines (Fassungen 10/2025 und V2 11/2025) sowie Paediatric Life Support Guideline 2025, Tabelle 1 „Approximate normal values" (Wiedergabe in Medscape: Paediatric Life Support – RCUK 2025 Guideline Summary).
• [133] Don't Forget the Bubbles. What's new – Resus Council Guidance 2025: Paediatric Life Support (Zusammenfassung der RCUK-Leitlinie 2025). dontforgetthebubbles.com, Suchstand 11/2026.
• [134] Advanced Life Support Group (ALSG). Advanced Paediatric Life Support (APLS) – A Practical Approach to Emergencies. Altersformeln zur Gewichtsschätzung.
• [135] Luscombe M, Owens B. Weight estimation in resuscitation: is the current formula still valid? Arch Dis Child 2007;92:412–415.
• [136] Fleming S, Thompson M, Stevens R et al. Normal ranges of heart rate and respiratory rate in children from birth to 18 years of age: a systematic review of observational studies. Lancet 2011;377:1011–1018.

This article does not replace clinical judgement in the individual case or the current summary of product characteristics and guidelines.