Vital Signs: What They Are, Why Doctors Check Them

Vital signs are core physiological measurements that provide a snapshot of basic body function.

The Four Classic Vitals

1. Blood pressure: Perfusion pressure; screens for hypertension, shock.
2. Heart rate: Cardiac output adequacy; detects arrhythmias, autonomic dysfunction.
3. Respiratory rate: Ventilation status; early marker of deterioration (sepsis, acidosis).
4. Temperature: Infection, inflammation, thermoregulation failure.

Often Included

• Oxygen saturation (SpO₂): Hypoxemia detection.
• Pain score: "Fifth vital sign" (subjective but clinically vital).

Clinical Utility

• Screening: Detect silent hypertension, tachycardia, fever.
• Monitoring: Track trends in chronic disease (HTN, HF, COPD) or acute illness.
• Triage & decision-making: Guide urgency, testing, disposition.
• Communication: Standardized language across providers/settings.

Accurate technique (cuff size, rest period, proper thermometer site) is essential for reliability.