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For the study, I use the combination of two different sensor technologies:

• smart ring
• chest belt

Smart Ring Final decision forOURA Ring.

Applied sensor technology:

• infrared photoplethysmography (PPG) = Optical method that uses infrared light to measure changes in blood volume
• red and infrared LEDs measure blood oxygen levels while sleep.
• green and infrared LEDs alternate to measure heart rate 24/7 and heart rate variability and respiration rate during sleep.
• digital sensor measures body temperature variations
• 3D accelerometer (acceleration) tracks movement and activity 24/7.
• gyroscope (rotation)

Chest belt The sensors of the chest belt use electrical detection to track the heart rate.

The combination of ring and belt allows both short-term changes and long-term developments to be observed. As the devices use different sensor technologies, they complement each other.