The Sleep Score computed by Biostrap is relative measure of quality of today’s sleep session with respect to the quality of your sleep sessions over the last 3 to 30 days.
We updated the algorithm for this after releasing version 2.0.0 of our app (late October 2018).
The new sleep-score calculation uses the following 10 factors:
- Total Sleep Time
- Sleep Goal
- Deep Sleep Percentage
- Total Number of Awakenings
- Sleep Latency (when sleep is recorded manually)
- Total Awake Time (between sleep wake-up and onset time)
- Average HR during the sleep duration.
- Arm & Leg Disturbance
- Snoring Disturbance
- Number of Low SPO2 readings during the sleep
Sleep Goal Achieved = Percentage of Total Sleep versus the Sleep Goal
Sleep Efficiency = Total Sleep Time versus Total Time In Bed
Sleep Score Penalties - Computed as follows:
Latency Penalty - Penalty is computed when latency is greater than 20 minutes.
Awakenings Penalties - Penalty is computed when total number of awakenings are greater than certain number.
Deep Sleep Penalty - Penalty is computed when Deep Sleep percentage is lesser than 35%.
Arm & Leg Disturbance Penalty - Penalty is computed based upon number of minutes of mild, moderate, and several movements.
Snoring Disturbance Penalty - Penalty is computed based upon number of minutes of mild, moderate, and several movements.
High Average-HR Penalty - When average-HR during the sleep is higher than “Average HR” for last 30 days of sleep.
Note - We do not use RHR, but instead, we use average of all the HR readings during the sleep session.
- Low SPO2 Penalty - Penalty is computed based upon number of SPO2 readings below 95.
Note - You may see “Low SPO2 Penalty” even if your average SPO2 is same as the baseline. Because, there may be few readings which are below 95, even though average is same as the baseline.
Sleep Score is computed by subtracting penalties from 100 and then multiplying it by Sleep Goal Achieved and Sleep Efficiency.