How EveryBand estimates Stress

EveryBand Stress is a 0–100 estimate of physiological context, based on heart rate relative to a resting reference and available nightly HRV context. It describes a pattern in the recorded signals. It does not directly measure your emotions, identify what caused a change or diagnose anxiety.

A higher value can appear for many reasons. The calculation alone cannot distinguish a demanding meeting from heat, caffeine, illness, sensor artifact or other influences. A low value does not prove that you feel calm or that a health concern is absent.

This page describes the documented implementation reviewed on 15 October 2026. The installed beta may differ. EveryBand is experimental wellness software, and these estimates are not validated medical measurements.

The calculation needs recorded heart rate and a valid resting-heart-rate reference. It looks at the elevation above that reference rather than applying one universal heart-rate threshold to everyone.

When local nightly RMSSD and a prior reference are available, their relationship adds a bounded adjustment. The current Full implementation keeps imported Apple Health SDNN separate from that nightly RMSSD input. A Health HRV value therefore should not be assumed to populate every part of Stress or Recovery.

Available motion and recorded workout intervals help filter periods where ordinary physical activity explains the elevated heart rate. This filtering relies on the available records: missing movement evidence cannot establish that a person was motionless. See the HRV method for the measurement distinction.

For an admitted heart-rate point, the current equation is:

Stress = 8 + 1.8 × max(0, heart rate − resting heart rate)
         + available HRV adjustment

The result is bounded from zero to 100. If both nightly HRV and its prior reference exist, the adjustment is based on their ratio and bounded between −15 and +15. If they do not exist, the adjustment is zero; it does not fabricate an HRV reading.

The constants are an explicit software heuristic. They are not a conversion from heart rate to a percentage probability of psychological stress. Two people with the same displayed value need not have the same experience or physiology.

Points inside recorded workouts are excluded. The app also excludes points within detected movement intervals or near supported motion above its threshold. It then sorts the remaining observations into a timeline.

The daily average weights points by time instead of taking a simple average of every sample. Each point's forward contribution is capped at five minutes. This limits the influence of sparse sampling; it does not establish uninterrupted coverage between distant observations.

Zone percentages refer to covered time, not automatically the entire day. No covered interval means no daily average. A latest observation is also different from a time-weighted daily result.

The Sleep calculation can use the fraction of covered sleep time in the high zone. That component has its own minimum-coverage requirement, and its interval breakdown rejects gaps longer than five minutes. It does not turn an uncovered night into a continuous stress record.

Energy Reserve can use inverse Stress as one available load input. This is a composite wellness calculation, not proof that a specific Stress point drained a measurable quantity of energy. Strain separately describes exertion, so workout effort and the filtered Stress timeline should not be read as equivalent measures.

Check the time and source of the observations, recording coverage and the resting reference before interpreting the number. Incomplete sync, missing daily context and permissions can explain an unavailable value. A connected device does not guarantee that all necessary records have arrived.

Treat an unexpected result as a reason to look at its context, not as a diagnosis. The model cannot assess symptoms or determine whether training is safe. Scores from different apps use different inputs and formulas; EveryBand does not claim parity with proprietary stress models.

EveryBand is independent and is not affiliated with, endorsed by or sponsored by WHOOP, Apple or Bevel. Their names identify third-party hardware, services and products.

Written by EveryBand. Published October 16, 2026; reviewed October 16, 2026. Product descriptions are subject to the installed build; third-party features and terms may change.

EveryBand is an independent app and is not affiliated with, endorsed by, or sponsored by WHOOP, Apple, or Bevel. Third-party product names and trademarks belong to their respective owners and are used only for factual compatibility and interoperability descriptions.

Other app and device names belong to their owners. EveryBand is also independent of Sixteen and its publisher. For corrections, contact EveryBand.

• How the estimates workRead the full explanation.
• How EveryBand measures HRVEveryBand keeps Apple Health SDNN separate from local nightly RMSSD estimates. Learn how intervals, overnight windows and missing data affect the result.
• How EveryBand calculates RecoveryEveryBand Recovery combines nightly RMSSD, resting heart rate and Sleep with personal history. It needs the current night and two prior complete baseline nights.
• How EveryBand calculates SleepEveryBand Sleep combines duration against estimated need, regularity, efficiency and sleep stress. Stages and missing data have separate limits.
• How EveryBand estimates EnergyEnergy Reserve is a wellness index combining available Recovery, Sleep, Strain and Stress. Calorie expenditure is a separate estimate with different inputs and limits.
• Data sources and compatibilityRead the full explanation.