Vital signs are five core measurements that reveal how well your body’s most basic functions are working: blood pressure, heart rate, respiratory rate, body temperature, and blood oxygen level. Each one has a normal range, and knowing where your numbers fall tells you whether something needs attention. Here’s how to read and interpret each one.
Blood Pressure: Two Numbers, One Reading
Blood pressure is written as one number over another, like 120/80. The top number (systolic) measures the force of blood against your artery walls when your heart beats. The bottom number (diastolic) measures that force between beats, when your heart is resting. Both are recorded in millimeters of mercury, abbreviated as mm Hg.
The categories break down like this:
- Normal: below 120/80 mm Hg
- Elevated: 120 to 129 systolic with diastolic still below 80
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic
- Severe hypertension: above 180/120 mm Hg
Only one of the two numbers needs to be high for the reading to count as elevated. So a reading of 135/75 falls into Stage 1 hypertension because the systolic number is in that range, even though the diastolic number looks fine. On the other end, systolic pressure below 90 paired with symptoms like dizziness or lightheadedness is a red flag for dangerously low blood pressure.
Getting an Accurate Blood Pressure Reading
Technique matters more than most people realize. Sitting on an exam table with your feet dangling, or resting your arm in your lap instead of on a surface, can push your reading several points higher than it actually is. For the most accurate result, sit in a chair with your back supported for at least five minutes before taking a reading. Rest your arm with the cuff on a table at chest height, feet flat on the floor, legs uncrossed.
Cuff size also affects accuracy. A cuff that’s too small will overestimate your blood pressure, and one that’s too large will underestimate it. Most home monitors come with a standard adult cuff that fits arm circumferences of about 27 to 34 centimeters (roughly 10.5 to 13.5 inches). If your upper arm measures 35 centimeters or more, you need a large adult cuff. You can check by wrapping a tape measure around the midpoint of your upper arm.
Heart Rate: Beats Per Minute
A normal resting heart rate for adults falls between 60 and 100 beats per minute. You’ll see this labeled as “HR” or “pulse” on monitors and printouts. Well-trained athletes often have resting rates in the 40s or 50s because their hearts pump more blood with each beat, but for most people, a rate consistently below 60 or above 100 at rest is worth discussing with a provider.
To check your own pulse, place two fingers (not your thumb, which has its own pulse) on the inside of your wrist just below the base of your thumb. Count the beats for 30 seconds and multiply by two. Your heart rate naturally rises with exercise, caffeine, stress, pain, and fever. A resting pulse above 110 or below 50 is considered a red flag in urgent care settings, especially when paired with symptoms like chest pain, fainting, or shortness of breath.
Respiratory Rate: Breaths Per Minute
The normal respiratory rate for a resting adult is 12 to 18 breaths per minute. One breath equals a full cycle of inhaling and exhaling. This vital sign is easy to overlook, but it’s one of the earliest indicators that something is wrong. A rate above 22 breaths per minute in an adult is a clinical red flag.
Counting your own breaths is tricky because the moment you focus on your breathing, you tend to change it. A better approach is to have someone else watch your chest rise and fall for 60 seconds while you’re sitting quietly and not aware they’re counting. On a hospital monitor, respiratory rate is usually displayed as “RR” or “resp.”
Body Temperature
The average normal body temperature is 98.6°F (37°C), but healthy people routinely range from 97°F to 99°F (36.1°C to 37.2°C) depending on the time of day, activity level, and where the measurement is taken. Your temperature tends to be lowest in the early morning and highest in the late afternoon.
A temperature of 100.4°F (38°C) or higher generally indicates a fever. In urgent care, a temperature of 102°F or above is flagged as a red flag requiring closer evaluation. For infants under two months old, even a rectal temperature of 100.4°F or higher is treated as potentially serious because young babies can’t fight infections the way older children and adults can.
Where you take the measurement matters. Oral readings are the most common at home. Forehead and ear thermometers are convenient but can read slightly lower or higher depending on the device. Rectal temperatures run about 0.5°F to 1°F higher than oral readings and are considered the most accurate for infants.
Blood Oxygen Level (SpO2)
A pulse oximeter clips onto your fingertip and displays your oxygen saturation as a percentage, labeled SpO2. For most people, a normal reading falls between 95% and 100%. If you have a chronic lung condition like COPD, your baseline may sit lower, and your provider can tell you what’s normal for you specifically.
An SpO2 of 92% or lower warrants a call to your healthcare provider. A reading of 88% or below is an emergency. These thresholds matter because oxygen saturation can drop significantly before you feel noticeably short of breath.
Several things can throw off a pulse oximeter’s accuracy. Nail polish, especially gel manicures, can cause the device to overestimate your actual oxygen level, which is particularly dangerous because it could mask a real drop. Cold fingers reduce blood flow to the fingertip, making the reading unreliable. Excessive movement during the reading also introduces error. For the most accurate result, sit still, use a warm finger with no nail polish, and wait for the number to stabilize for a few seconds before reading it.
How Children’s Vitals Differ From Adults
Children are not small adults when it comes to vital signs. Their normal ranges are significantly different, and using adult ranges to judge a child’s numbers will lead you astray. In general, younger children have faster heart rates and faster breathing rates than adults, and these numbers gradually slow as children grow.
- Newborns (0 to 3 months): heart rate 110 to 160 bpm, respiratory rate 30 to 60 breaths per minute
- Infants (3 to 12 months): heart rate 90 to 150 bpm, respiratory rate 25 to 45 breaths per minute
- Toddlers (1 to 3 years): heart rate 80 to 125 bpm, respiratory rate 20 to 30 breaths per minute
- School-age children (6 to 12 years): heart rate 60 to 100 bpm, respiratory rate 14 to 22 breaths per minute
By the time children reach age 6 to 12, their heart rate and respiratory rate ranges start to overlap with adult values. A pulse oximeter reading below 94% in a child is considered a red flag, just as it is for adults.
Reading Vitals on a Monitor
If you’re looking at a bedside monitor in a hospital or an at-home device, the numbers are usually color-coded and labeled with abbreviations. Here’s what to look for:
- HR or pulse: heart rate in beats per minute
- BP or NIBP: blood pressure, displayed as systolic/diastolic (sometimes with a third number in parentheses, the mean arterial pressure, which is mainly useful to clinicians)
- SpO2: oxygen saturation as a percentage
- RR or resp: respiratory rate in breaths per minute
- Temp: temperature in Fahrenheit or Celsius
Hospital monitors will beep when a number falls outside a set range. Those alarms don’t always mean something is wrong. Movement, a loose sensor, or a cuff that shifted can all trigger false alarms. But consistent readings outside the normal ranges described above, especially more than one vital sign trending in the wrong direction at the same time, indicate something your body is struggling to compensate for. A fast heart rate combined with low blood pressure and low oxygen saturation, for example, paints a much more urgent picture than any one of those numbers alone.