Cardio load can change when a supported workout is added or corrected, and it can also change as your recent training pattern moves forward. A change today does not always mean that you completed a workout today.
Start with the workout list
Open the cardio-load detail and check which sessions appear on the affected dates. Then compare them with Apple Health or your connected health platform.
Look for:
- a new workout that synced later than expected;
- a corrected workout duration, type, or start time;
- heart-rate data that became available after the workout;
- a duplicate session written by more than one app; or
- a workout assigned to a different date because of time-zone or clock settings.
Why the values can move on a rest day
Fitness and Fatigue describe patterns across time, not permanent totals. Recent training has more influence on Fatigue, while Fitness reflects the longer-term pattern. As the days move forward, the relationship between those patterns can change even when no new session is added.
That is expected model behavior. It does not mean Zolt invented a workout or measured your fitness directly.
Check heart-rate completeness
Supported cardio workouts use duration and available heart-rate intensity. A session with missing samples, a loose sensor, implausible spikes, or different zone settings may contribute differently from what you expected.
Open the original workout and review the heart-rate chart. If the chart has long gaps or values that do not match the session, treat the load as incomplete context.
Read all three values together
- Fitness describes the longer-term cardio training pattern.
- Fatigue describes the more immediate recent pattern.
- Form describes the relationship between them.
A demanding session can move the recent pattern more quickly than the longer-term one. During lighter training, the recent pattern can ease sooner. The meaning comes from the direction and your plan, not from trying to maximize every number.
Checks to make
- Identify the date and value that changed.
- Compare the workout list with the source platform.
- Check for late sync, corrections, duplicates, and time-zone changes.
- Review workout duration and heart-rate completeness.
- Confirm that your heart-rate settings are current.
- Compare the chart with your recent training plan.
If the source records are correct but Zolt shows the wrong workout, date, or duplicate load, contact support with screenshots of both views.