Heart rate often changes after sleep begins and continues to vary across the night. Zolt's heart-rate dip view helps you compare that overnight change with your own recent pattern.
How to interpret it
Treat the result as context, not a pass or fail grade.
- Compare it with your own usual range from the same device.
- Look for a repeated shift rather than reacting to one night.
- Read it with total sleep, awake time, training, and how you feel.
- Check data completeness before treating an unusual value as meaningful.
Sleep stages, movement, stress, illness, medication, alcohol, exercise, and other factors can all coincide with changes in overnight heart rate. The metric does not identify the cause.
Why two similar nights can look different
Wearables take samples and estimate sleep boundaries. A loose fit, low battery, a shorter recording window, or a different source can change the available record. Normal night-to-night variation can also change the result.
That is why trend context matters more than a universal percentage. Zolt is designed to help you see the pattern without turning one reading into a medical conclusion.
If the result looks wrong
- Check the heart-rate and sleep records in the connected health platform.
- Confirm that the full sleep period was recorded.
- Look for gaps in heart-rate samples.
- Review device fit, battery, and permissions.
- Check whether multiple devices contributed overlapping records.
If the original records are complete but the Zolt view differs, contact support with the affected date and screenshots.
Medical limits
An overnight heart-rate trend cannot diagnose cardiovascular disease, sleep apnea, overtraining, or poor recovery. Speak with a healthcare professional about persistent changes or symptoms. Seek urgent care for chest pain, fainting, severe shortness of breath, or other urgent symptoms.