Apple Watch HRV Stress Monitoring | Cortisol+

Your HRV in context

Cortisol+ is an Apple Watch stress tracking app that brings available HRV, resting heart rate, sleep and activity into one view. Its wellness score summarizes the app's interpretation of those inputs. It is not a cortisol measurement.

What you can do

• Review the biometric factors contributing to your current score.
• Compare available readings with your history.
• Look at sleep and activity alongside stress and recovery trends.
• Use guided breathing and note how you feel before and after.

Core analysis requires an active subscription or an eligible trial. Downloading the app is free; the in-app offer shows the current price, renewal interval and trial conditions.

What HRV means here

Apple Watch provides HRV as SDNN. The app uses that value relative to a baseline, alongside other signals. The research on HRV and stress describes autonomic responses across studies; it does not establish that a person's hormone level can be inferred from one HRV reading.

Data source and recording conditions matter. SDNN and RMSSD are different statistics, and a number from one device cannot always be compared directly with another. Background measurements are intermittent rather than a continuous cortisol stream.

Personalization and missing data

The scoring baseline uses up to 30 days of stored readings and gradually blends personal history with defaults. Available factors and freshness affect the calculation. The methodology page lists the actual weights, baseline rules and limitations.

Use trends to support reflection

Changes in HRV can coincide with exercise, illness, alcohol, medications, sleep or recording conditions. A chart cannot isolate the cause or prove that a supplement or intervention worked. Pair readings with a stress and sleep journal, and discuss concerning symptoms with a clinician.

Read what Apple Watch can tell you about cortisol and stress, or see download and subscription information.