Apple Health metrics, explained

What each Apple Watch and iPhone health number means, what is normal, and how to keep an eye on it.

• Resting Heart Rate
  Your heart rate when you are calm and still, a simple read on cardiova
• Heart Rate Variability (HRV)
  The beat-to-beat variation in your heart rhythm, often used as a recov
• VO2 Max (Cardio Fitness)
  An estimate of the most oxygen your body can use during hard exercise,
• Blood Oxygen (SpO2)
  The percentage of oxygen carried in your blood, measured at the wrist.
• Respiratory Rate
  How many breaths you take per minute, recorded while you sleep.
• Steps
  Your daily step count, the simplest measure of everyday movement.
• Sleep Duration
  How long you slept last night, from Apple Watch or iPhone Sleep.
• REM Sleep
  Time spent in REM, the stage tied to dreaming and memory processing.
• Deep Sleep
  Time in the slow-wave stage where the body does most of its physical r
• Core Sleep
  Time in light-to-moderate sleep, which makes up the largest share of t
• Awake Time During Sleep
  How long you were awake between falling asleep and getting up.
• Wrist Temperature
  How your sleeping wrist temperature deviates from your own baseline.
• Walking Heart Rate Average
  Your average heart rate during regular walking, a gentle fitness indic
• Heart Rate Recovery
  How fast your heart rate drops after hard exercise, a marker of cardio
• Heart Rate
  Your latest and daily heart rate range from Apple Watch.
• Walking Speed
  How fast you walk on level ground, a surprisingly strong predictor of
• Walking + Running Distance
  The total distance you cover on foot each day.
• Walking Step Length
  The distance between your steps, a mobility measure that shortens with
• Walking Asymmetry
  How often your steps are uneven, one side taking a different time than
• Double Support Time
  The share of each step with both feet on the ground, a balance and gai
• Walking Steadiness
  Apple's score for how steady you are on your feet and how likely you a
• Stand Hours
  How many hours of the day you stood and moved for at least a minute.
• Exercise Minutes
  Minutes of brisk activity at or above a brisk walk, tracked by the Exe
• Active Energy
  Calories burned through movement and exercise, excluding resting metab
• Body Weight
  Your weight trend from a smart scale or manual entries.
• Body Mass Index (BMI)
  A quick screening ratio of weight to height.
• Body Fat Percentage
  The share of your weight that is fat, from a smart scale or manual ent

This page is general information, not medical advice. Ranges vary by age, sex, fitness and device. Talk to a clinician about anything that worries you.