Vital signs are a small set of body measurements that reveal how well your most basic life-sustaining functions are working. The four primary vital signs are body temperature, heart rate (pulse), respiratory rate (breathing rate), and blood pressure. A fifth measurement, oxygen saturation, is now checked so routinely that many clinicians treat it as a standard vital sign. Together, these numbers give a quick snapshot of your cardiovascular, respiratory, and metabolic health.
Body Temperature
Your body temperature reflects how well your internal thermostat is working. The long-cited “normal” is 98.6 °F (37 °C), but healthy temperatures actually fluctuate throughout the day. They tend to be lowest in the early morning and highest in the late afternoon. Gender, recent physical activity, food and fluid intake, and, in women, the stage of the menstrual cycle all shift the number slightly.
A fever is generally defined as an oral or rectal temperature of 100.4 °F (38 C) or higher. Armpit readings run a bit cooler, so 99 °F (37.2 °C) from an armpit thermometer is considered a fever. Ear and forehead (temporal artery) thermometers use the same 100.4 °F cutoff as oral readings. The method you use matters, so it helps to know which threshold matches your thermometer.
Heart Rate (Pulse)
Heart rate counts how many times your heart beats in one minute. For adults over age 10, the normal resting range is 60 to 100 beats per minute (bpm). A resting rate consistently above 100 bpm is called tachycardia, while a rate below 60 bpm is called bradycardia. Neither is automatically dangerous. Well-trained athletes often have resting rates in the 40s or 50s because their hearts pump more blood per beat.
Your pulse fluctuates with exercise, illness, injury, emotions, and certain medications. To get a reliable resting number, sit quietly for a few minutes first. You can feel your pulse on the inside of your wrist (thumb side) or on the side of your neck just below the jawline. Count beats for 30 seconds and multiply by two.
Children’s Heart Rates
Kids have faster hearts than adults. A newborn’s awake heart rate can range from 85 to 205 bpm. Between 3 months and 2 years, the typical awake range is 100 to 190 bpm. From ages 2 to 10 it drops to 60 to 140 bpm, and by adolescence the range aligns with the adult standard of 60 to 100 bpm. Sleeping rates run lower across every age group.
Respiratory Rate
Respiratory rate is the number of breaths you take per minute. A normal adult rate at rest is 12 to 20 breaths per minute. Breathing faster than that range (tachypnea) can signal fever, infection, pain, anxiety, or a lung or heart problem. Unusually slow breathing can occur with certain medications, head injuries, or metabolic conditions.
Children breathe faster than adults. Infants typically take 30 to 60 breaths per minute, toddlers 24 to 40, preschoolers 22 to 34, and school-age children 18 to 30. By adolescence the rate settles into the adult range of 12 to 16. Fever and illness push the rate higher at any age.
Respiratory rate is one of the easiest vital signs to check at home. Watch the chest rise and fall for 30 seconds and double the count. Try to observe breathing when the person is calm and unaware they’re being watched, since conscious attention to breathing tends to change the rhythm.
Blood Pressure
Blood pressure measures the force of blood pushing against artery walls. It’s recorded as two numbers: systolic (the pressure when your heart contracts) over diastolic (the pressure between beats). The 2025 guidelines from the American Heart Association and American College of Cardiology define the categories for adults as follows:
- Normal: below 120/80 mm Hg
- Elevated: systolic 120 to 129 and diastolic below 80
- Stage 1 hypertension: systolic 130 to 139 or diastolic 80 to 89
- Stage 2 hypertension: systolic 140 or higher, or diastolic 90 or higher
If your systolic and diastolic numbers fall into two different categories, the higher category applies. A reading of 128/85, for example, would be classified as Stage 1 hypertension because the diastolic number falls in that range even though the systolic number is only in the “elevated” zone. Blood pressure that is too low also causes problems. Readings below about 90/60 can produce dizziness, fainting, and fatigue.
Getting an Accurate Reading
Blood pressure is the vital sign most sensitive to how and when you measure it. The CDC recommends sitting in a chair with your back supported for at least five minutes before a reading. Both feet should be flat on the floor, legs uncrossed, and your arm resting on a table at chest height. The cuff goes on bare skin, not over a sleeve. Crossing your legs or letting your arm hang at your side can push the reading artificially higher. Avoid caffeine and smoking for 30 minutes beforehand, and try to relax. Body movement or an irregular heart rhythm can also throw off digital monitors, so staying still during the reading matters.
Oxygen Saturation
Oxygen saturation (SpO2) measures the percentage of your red blood cells that are carrying oxygen. A small clip-on device called a pulse oximeter shines light through your fingertip to estimate the number. Healthy values range from 95% to 100%. Readings below 90% are considered low and typically require medical attention. Conditions like pneumonia, asthma, COPD, heart failure, and severe anemia can drive the number down.
Pulse oximeters became household items during the COVID-19 pandemic, and they’re useful for monitoring chronic lung or heart conditions at home. Accuracy can be affected by cold fingers, dark nail polish, and poor circulation, so warm your hands and remove nail polish before checking if your reading seems unexpectedly low.
What Changes Your Vital Signs
All vital signs shift in response to everyday activities. Exercise raises heart rate, breathing rate, and blood pressure temporarily. Stress and strong emotions do the same. Fever increases both pulse and respiratory rate because your body is working harder to fight infection. Even the time of day matters: body temperature is lowest in the early morning and peaks in the late afternoon, while blood pressure often dips during sleep and rises after waking.
Medications are another major factor. Some cold medicines raise blood pressure. Beta-blockers lower heart rate. Pain relievers that contain opioids can slow breathing. If you’re tracking your vital signs at home, knowing which medications you take helps you interpret numbers that seem off. For the most consistent results, try to measure at the same time of day, under the same conditions, and after sitting quietly for a few minutes.
Normal Ranges at a Glance
- Temperature: around 98.6 °F (37 °C) orally; fever at 100.4 °F (38 °C) or above
- Heart rate (adult): 60 to 100 bpm at rest
- Respiratory rate (adult): 12 to 20 breaths per minute at rest
- Blood pressure (adult): below 120/80 mm Hg is normal
- Oxygen saturation: 95% to 100%
A single abnormal reading doesn’t necessarily signal a problem. Trends over time tell a more reliable story than any one measurement. If you’re tracking vital signs at home, writing down the numbers along with the date, time, and any relevant context (just exercised, felt anxious, skipped medication) gives you and your healthcare provider a much clearer picture.