The accuracy of the Fitbit Versa 4's SpO2 sensor during sleep is a topic of interest for those monitoring blood oxygen levels, particularly for conditions like sleep apnea. Here's a detailed overview:
How SpO2 Sensors Work
Fitbit devices, including the Versa 4, use red and infrared sensors to measure SpO2 levels. These sensors shine light onto the skin and measure the reflected light to estimate oxygen saturation in the blood. Richly oxygenated blood reflects more red light, while poorly oxygenated blood reflects more infrared light[10].Accuracy Compared to Clinical Devices
While Fitbit's SpO2 sensors are not as accurate as those used in hospitals, they can provide useful insights into general trends in blood oxygen levels during sleep[4]. However, there can be discrepancies between Fitbit readings and those from clinical-grade oximeters. For example, a user reported that their Fitbit Sense showed SpO2 levels ranging from 92% to 98% with an average of 95%, while a finger oximeter recorded levels frequently dropping into the low 80s with an average of 91%[1].Factors Affecting Accuracy
Several factors can influence the accuracy of SpO2 readings on Fitbit devices:- Sleep Quality: The device must be worn correctly during sleep to ensure accurate readings.
- Device Charging: The device should be well-charged to maintain continuous monitoring.
- Environmental Conditions: Changes in body temperature or environmental conditions might affect heart rate and SpO2 readings[9].
Usage and Interpretation
Fitbit's SpO2 sensor is active during sleep and reports an average SpO2 level for the sleep session. Users can view this data in the Fitbit app under the Health Metrics section[10]. While Fitbit's sleep staging accuracy is around 69% in 30-second intervals[7], the SpO2 feature is not yet integrated into sleep stage analysis but can provide valuable insights into oxygen saturation trends.In summary, while the Fitbit Versa 4's SpO2 sensor can offer useful data on blood oxygen levels during sleep, its accuracy may vary compared to clinical devices. It is essential to consider the limitations and potential factors affecting readings when interpreting SpO2 data from Fitbit devices.
Citations:[1] https://www.reddit.com/r/fitbit/comments/ukcx1n/accuracy_of_spo2/
[2] https://www.androidcentral.com/how-use-spo2-sensor-and-watch-face-your-fitbit-smartwatch
[3] https://pmc.ncbi.nlm.nih.gov/articles/PMC10337940/
[4] https://www.techradar.com/news/fitbit-releases-a-special-update-to-help-you-check-your-oxygen-saturation-levels
[5] https://mobilemob.com.au/blogs/news/fitbit-versa-4-specifications
[6] https://www.reddit.com/r/fitbit/comments/hvxha0/what_you_probably_didnt_know_about_your_fitbit/
[7] https://www.internationalsleepcharity.org/blog/what-i-learned-from-tracking-my-sleep-with-fitbit-for-two-months
[8] https://community.fitbit.com/t5/Versa-4/What-does-SpO2-measures-on-Versa-4/td-p/5283635
[9] https://community.fitbit.com/t5/Other-Versa-Smartwatches/Accuracy-of-SPO2-readings/td-p/4516053
[10] https://support.google.com/fitbit/answer/14226120?hl=en