A handful of numbers quickly sketches physiological stability. Vital signs are the basic clinical measurements of body temperature, heart rate, respiratory rate, and blood pressure that indicate the state of essential body functions.

Oxygen saturation is often included as a fifth vital sign. Abnormalities may be the first warning of infection, shock, respiratory failure, or other acute change. Trends over time matter more than single values. Measurement technique and appropriate equipment for age and size affect accuracy.

In hospitals, vital signs are recorded at intervals matched to patient acuity; continuous monitoring is used in critical care. Early-warning scores derived from vital signs help trigger rapid response before frank collapse. Every clinical encounter begins with attention to these fundamental data.

• Core measurements of temperature, pulse, respiration, and blood pressure
• Often include oxygen saturation
• Provide early warning of physiological deterioration
• Interpreted as trends as well as absolute values