Overview
Vital signs are objective measurements of the body’s most basic functions. Taken together, they provide a snapshot of how well the body is working and, when repeated over time, show whether a patient is improving or getting worse. This lesson covers the core vital signs — pulse, respirations, blood pressure, temperature, and oxygen saturation — along with skin signs and pupils, and it gives the normal adult ranges you can use as reference points.
Important: This is educational content and not a substitute for certified hands-on training. Numbers alone do not tell the whole story; they must always be interpreted alongside how the patient looks and feels. In a real emergency, call your local emergency number immediately.
Accurate measurement takes practice. Rushing, counting a pulse for too short a time, or letting a patient know you are watching their breathing can all distort readings. Whenever possible, gather a full set of vitals rather than a single number, and record the time each set was taken so changes can be compared later.
Normal Adult Ranges
Memorizing typical ranges lets you quickly recognize when something is abnormal.
| Vital sign | Normal adult range |
|---|---|
| Pulse (heart rate) | 60–100 beats per minute |
| Respiratory rate | 12–20 breaths per minute |
| Blood pressure | Around 120/80 mmHg (systolic < 120, diastolic < 80 is ideal) |
| Temperature | About 98.6 °F (37 °C) |
| Oxygen saturation (SpO2) | 95–100% on room air |
These are general adult values; normal ranges differ for children and infants, who tend to have faster pulses and breathing.
Pulse
The pulse reflects each heartbeat felt in an artery. Common sites are the radial artery at the wrist and the carotid artery in the neck. To measure it:
- Place two fingers (not your thumb) over the artery.
- Press gently until you feel the beat.
- Count the beats for 30 seconds and multiply by 2, or count a full 60 seconds for irregular rhythms.
Note not only the rate but also the rhythm (regular or irregular) and strength (strong or weak). A fast, weak pulse can be an early sign of shock.
Respirations
The respiratory rate is the number of breaths per minute. Because people can consciously change their breathing, count respirations discreetly, often right after taking the pulse while your fingers are still on the wrist. Watch the chest rise and fall for 30 seconds and double it. Also observe the effort of breathing — labored breathing, use of neck muscles, or noisy breathing all signal trouble.
Blood Pressure
Blood pressure is the force of blood pushing against artery walls. It is written as systolic over diastolic:
- Systolic — the higher number, pressure while the heart contracts.
- Diastolic — the lower number, pressure while the heart relaxes.
A reading of 120/80 mmHg is a common reference for a healthy adult. Very high readings suggest hypertension, while a falling blood pressure can be a late and dangerous sign of shock.
Temperature, Oxygen Saturation, Skin, and Pupils
Temperature normally sits near 98.6 °F (37 °C). A fever suggests infection, while a very low temperature indicates hypothermia.
Oxygen saturation (SpO2), measured with a pulse oximeter clipped to a finger, shows the percentage of hemoglobin carrying oxygen. Normal is 95–100%; lower values suggest the patient is not oxygenating well.
Skin signs are quick and informative. Assess color, temperature, and moisture:
| Finding | Possible meaning |
|---|---|
| Pink, warm, dry | Usually normal |
| Pale, cool, sweaty | Poor circulation, shock |
| Blue (cyanosis) | Low oxygen |
| Flushed, hot | Fever or heat illness |
Capillary refill — pressing a nail bed and watching color return in under about 2 seconds — offers a rough circulation check, most useful in children.
Pupils should be equal, round, and reactive to light. Unequal or unreactive pupils can indicate a serious brain problem, and pinpoint or very dilated pupils may point to certain drug effects or injuries.
Clinical Relevance
Single readings matter, but trends matter more. A blood pressure of 118/78 mmHg is reassuring on its own; the same number falling to 96/60 over ten minutes while the pulse climbs is an alarm bell for developing shock. This is why responders take a baseline set of vitals early and then reassess. Interpreting vital signs together, rather than in isolation, turns raw numbers into a meaningful picture of whether a patient is stable, improving, or deteriorating, and guides decisions about how urgently more advanced care is needed.