True Age includes a confidence score that tells you how reliable your current estimate is. Here's how confidence works and what the three levels mean.

What confidence measures

Confidence reflects how complete and recent your biomarker data is. Each of your four biomarkers contributes to the overall confidence score.

Your confidence score isn't about whether your wearable is accurate. It's about whether we have enough recent data points to calculate a reliable biological age estimate.

The three confidence levels

High confidence

You have excellent data coverage. All four biomarkers have recent, complete data within the optimal ranges.

Medium confidence

You have good data coverage, but one or more biomarkers could use more frequent readings or more recent measurements.

Low confidence

You have the minimum data needed to calculate True Age, but data is limited or less recent for one or more biomarkers.

How confidence is calculated

Your overall True Age confidence is determined by the lowest scoring biomarker. This means if three biomarkers have high confidence but one has low confidence, your True Age will show low confidence overall.

Current week biomarker values don't count toward True Age data requirements—they'll be used for next week's True Age update.

Each biomarker is evaluated separately:

RHR and HRV (daily readings)

These need consistent daily tracking over the past 4 complete weeks.

High: 24+ days with readings
Medium: 14–23 days with readings
Low: 4–13 days with readings
No True Age: Fewer than 4 days

VO2max and LBMI (latest reading)

These need recent measurements, not necessarily daily.

High: Reading is from last week
Medium: Reading is 2 weeks old
Low: Reading is 3–4 weeks old
No True Age: Reading is more than 4 weeks old

How the lookback window works

True Age uses data from the past 4 complete weeks to calculate your biological age.

What this means:

Your True Age updates every Monday, using data from the previous 4 full weeks (Monday to Sunday)
This lookback period is always exactly 4 weeks (28 days) of complete weekly data
You need at least 4 days of RHR and HRV readings plus one VO2max and one LBMI reading across those 4 weeks
Confidence improves when you have more frequent readings for RHR/HRV and more recent readings for VO2max/LBMI

Example: If today is Thursday, your current True Age is based on the 4 complete weeks ending last Sunday. Data from this week (Monday through today) will count toward next Monday's True Age update.

Starting with historical data

If you have 4+ weeks of historical data

You'll see a True Age immediately. Your initial confidence depends on how complete and recent your data is within the last 28 days.

If you have 1–3 weeks of historical data

You'll see a True Age immediately if you meet the minimum requirements. Your confidence will likely be low or medium and will improve as you accumulate more data.

If you're starting fresh

You'll need to gather data for at least 1 week with the minimum requirements before seeing your first True Age.

Why confidence matters

Low and medium confidence: Build consistency

Your True Age may fluctuate more week to week as new data comes in. This is normal. Focus on building a consistent data collection habit:

Wear your device consistently, especially at night for RHR and HRV
Record activities that update VO2max (outdoor walks, runs)
Keep weight and body composition measurements current

High confidence: Trust the trend

Your True Age is now stable enough to reveal meaningful patterns. Changes at this confidence level are more likely to reflect real shifts in your biomarkers rather than data gaps.