The baseline and its 20 sessions
Why the baseline card says 0 of 20, what Sentinel uses before it is calibrated, and how the figure is worked out.
What this does
Your baseline is what “normal” means for your body. Sentinel compares every live reading against it, because a heart rate of 92 is unremarkable for one person and a warning sign for another. Since Sentinel judges physiology rather than trading, this personal reference point is the thing that makes its alerts worth anything.
The card is called Health Metric Baseline on the web and Baseline Calibration in the apps. It holds three figures, a badge and a progress bar.
The badge has three states. Collecting at zero sessions, Calibrating between one and nineteen, and Calibrated at twenty or more.
The three figures are your session heart rate baseline in beats per minute, your average HRV in milliseconds, and your average sleep in hours. Any of them without real data behind it shows “Collecting data” rather than an invented number.
Until it is calibrated, Sentinel runs on safe starting values: resting heart rate 65, session heart rate 75, HRV 50 ms and sleep 7 hours. The card says so:
Sentinel remains operational with safe starting thresholds while it learns from your first session.
Before you start
“0 / 20 sessions” on a new account is the correct starting state. Sentinel works from day one.
The window rolls. It always uses your twenty most recent qualifying sessions, so the baseline keeps tracking your current fitness rather than freezing after the twentieth.
A session qualifies if its average heart rate lands between 35 and 220 bpm, it has a real start and end, and it produced at least one bucket of samples. Sessions longer than six hours are trimmed to six for this purpose.
Every qualifying session counts once, whatever its length. A twenty-minute session weighs the same as a four-hour one, because each contributes one time-normalised average.
Resting heart rate, HRV and sleep come from the health data on the days those sessions ran, using a median for heart rate and HRV and a trimmed mean for sleep.
The server holds the result for 24 hours. Recalculate forces a rebuild before that.
Steps
- Open VEXA Sentinel from the sidebar.
- Stay on the Overview tab and find the Health Metric Baseline card.
- Read the badge and the “N / 20 sessions” progress bar.
- Click Recalculate if you want it rebuilt now.
- Open Home, then tap Sentinel.
- Find the Baseline Calibration card under the live card.
- Read the badge and the progress bar.
- Tap Recalculate to rebuild it from your recent sessions.
- Open Home, then tap Sentinel.
- Find the Baseline Calibration card under the live card.
- Read the badge and the progress bar.
- Tap Recalculate to rebuild it from your recent sessions.
What you should see
A badge, three metric tiles, a progress bar reading “N / 20 sessions”, and a freshness stamp such as “Updated Jul 24, 9:15”.
While calibrating, the helper line names the gap: “Your 7-session baseline is active. 13 more sessions for full calibration.”
Once calibrated it reads: “Baseline is fully calibrated from your Sentinel sessions.”
On the live card, the deviation readout under your heart rate (“+12.4% above baseline”) is measured against this number, so it becomes more meaningful as the count climbs.
If it doesn’t work
It has said 0 sessions for weeks even though you have run sessions. Open the Sentinel page and tap Recalculate. Opening the page also triggers a rebuild when a baseline is missing or more than a day stale, so one visit usually resolves it.
HRV shows “Collecting data” and never fills in. Your device does not send beat-to-beat data during a session, or nothing has written overnight HRV into Apple Health or Health Connect. See Which heart rate devices work.
Sleep shows “Collecting data”. Nothing is recording your sleep. Wear the watch overnight.
The number looks too high. Short stressful sessions count as much as long calm ones. Run a few ordinary sessions and it settles, or tap Recalculate after they land.
Related
Related
Still stuck? Email support@vexatrade.ai.