As you know, we calculate the stress level based on HRV data. For determining stress, we use not some proprietary algorithms, but the Baevsky Stress Index (BSI), which was developed several decades ago and is applied in space medicine.
There were no issues with the actual calculation of the index, and we have always provided and continue to provide the correct absolute value.
However, after analyzing numerous measurements, we concluded that our norms for interpreting this value were very strict. After processing hundreds of thousands of measurements, we decided to change the norms and the calculation of the percentage value.
As with the index itself, we decided not to reinvent the wheel but to use existing standards and align our norms with the Kubios app.
Kubios is a truly excellent (and probably one of the best) applications used by professional athletes worldwide. Although Kubios displays the square root of the Baevsky Stress Index for stress levels, we continue to show the original value.
So now, if you train professionally and use Kubios, Wellhero’s norms will match it.
Here are our current BSI norms:
0 – 30: Rest
30 – 50: Low Stress
50 – 150: Normal Stress
150 – 500: Elevated Stress
500 – 900: High Stress
900+: Very High Stress
Additionally, we have updated all past calculations and norms for previous records. All past posts in the news feed will show a slightly lower stress level percentage than before, while the original value will remain unchanged.