System and method for health monitoring by an ear piece
A biosensor includes an optical circuit that obtains a plurality of photoplethysmography (PPG) signals from light at different wavelengths that is reflected from or transmitted through tissue of a user. A processing circuit determines a measurement value for a nitric oxide (NO) level in blood flow using first and second PPG signals and determines an insulin response from caloric intake using the measurement value for the NO level in blood flow. The first PPG signal is obtained from light at a wavelength having a high absorption coefficient for NO in blood flow and the second PPG signal is obtained from light at a second wavelength having a low absorption coefficient for NO in blood flow. The processing circuit also determines one or more phases of digestion using at least one or more of the plurality of PPG signals.
1. A biosensor, comprising:
an optical circuit configured to obtain a plurality of photoplethysmography (PPG) signals, wherein a first PPG signal is obtained from light at a first wavelength that is reflected from or transmitted through tissue of a user and a second PPG signal is obtained from light at a second wavelength reflected from or transmitted through the tissue of the user, wherein the first wavelength has a high absorption coefficient for NO and the second wavelength has a low absorption coefficient for NO; and
at least one processing circuit configured to:
determine a measurement value for a nitric oxide (NO) level in blood flow using the first PPG signal and the second PPG signal; and
determine an insulin response from caloric intake using the measurement value for the NO level in blood flow.
2. The biosensor of claim 1 , wherein the at least one processing circuit is further configured to determine a level of glucose in blood flow using the measurement value for the NO level in blood flow.
3. The biosensor of claim 1 , wherein the at least one processing circuit is further configured to determine a value R λ1,λ2 using the first PPG signal and the second PPG signal by:
determining a value L λ1 using the first PPG signal, wherein the value L λ1 isolates an alternating current (AC) component of the first PPG signal;
determining a value L λ2 using the second PPG signal, wherein the value L λ2 isolates an AC component of the second PPG signal; and
determining the value R λ1,λ2 from a ratio of the value L λ1 and the value L λ2 , wherein the value R λ1,λ2 is the measurement value for the NO level in blood flow.
4. The biosensor of claim 3 , wherein the at least one processing circuit is further configured to determine the caloric intake using the value R λ1,λ2 for the measurement value for the NO level in blood flow.
5. The biosensor of claim 4 , wherein the first wavelength is in a range of approximately 370 nm to 410 nm.
6. The biosensor of claim 1 , wherein the at least one processing circuit is further configured to determine one or more phases of digestion using at least a third PPG signal of the plurality of PPG signals that is obtained from light at a third wavelength reflected from or transmitted through the tissue of the user, wherein the phases of digestion include a phase 1 stage or a phase 2 stage.
7. The biosensor of claim 6 , wherein the third wavelength is approximately 592 nm and the second wavelength is in the IR range.
8. The biosensor of claim 7 , wherein the at least one processing circuit is further configured to determine one or more phases of digestion using at least a third PPG signal of the plurality of PPG signals by:
determining a value L λ3 using the third PPG signal, wherein the value L λ3 isolates an alternating current (AC) component of the third PPG signal;
determining a value L λ2 using the second PPG signal, wherein the value L λ2 isolates an AC component of the second PPG signal; and
determining a value R λ3,λ2 from a ratio of the value L λ3 and the value L λ2 .
9. The biosensor of claim 8 , wherein the at least one processing circuit is further configured to determine the one or more phases of digestion using the value R λ3,λ2 .
10. A biosensor, comprising:
an optical circuit configured to obtain a plurality of photoplethysmography (PPG) signals, wherein a first PPG signal is obtained from light at a first wavelength that is reflected from or transmitted through tissue of a user and a second PPG signal is obtained from light at a second wavelength reflected from or transmitted through the tissue of the user, wherein the first wavelength is approximately 592 nm and the second wavelength is in the IR range; and
at least one processing circuit configured to determine one or more phases of digestion using the first PPG signal and the second PPG signal, wherein the phases of digestion include a phase 1 stage or a phase 2 stage.
11. The biosensor of claim 10 , wherein the at least one processing circuit is further configured to determine one or more phases of digestion using the first PPG signal and the second PPG signal by:
determining a value L λ1 using the first PPG signal, wherein the value Li isolates an alternating current (AC) component of the first PPG signal;
determining a value L λ2 using the second PPG signal, wherein the value L λ2 isolates an AC component of the second PPG signal; and
determining a value R λ1,λ2 from a ratio of the value L λ1 and the value L λ2 .
12. The biosensor of claim 11 , wherein the at least one processing circuit is further configured to determine a measurement value for a nitric oxide (NO) level in blood flow using a third PPG signal and the second PPG signal; and
determine an insulin response from caloric intake using the measurement value for the NO level in blood flow.
13. The biosensor of claim 12 , wherein the at least one processing circuit is further configured to determine a level of glucose in blood flow using the measurement value for the NO level in blood flow.
14. The biosensor of claim 12 , wherein the at least one processing circuit is further configured to determine a measurement value for a nitric oxide (NO) level in blood flow using a third PPG signal and the second PPG signal by:
determining a value L λ3 using the third PPG signal, wherein the value L λ3 isolates an alternating current (AC) component of the third PPG signal;
determining a value L λ2 using the second PPG signal, wherein the value L λ2 isolates an AC component of the second PPG signal; and
determining a value R λ3,λ2 from a ratio of the value L λ3 and the value L λ2 , wherein the value R λ3,λ2 is the measurement value for the NO level in blood flow.
15. The biosensor of claim 12 , wherein the third PPG signal is obtained from light at a third wavelength, and wherein the third wavelength is in a range of approximately 370 nm to 410 nm.
16. A biosensor, comprising:
an optical circuit configured to obtain a plurality of photoplethysmography (PPG) signals, wherein a first PPG signal is obtained from light at a first wavelength that is reflected from or transmitted through tissue of a user and a second PPG signal is obtained from light at a second wavelength reflected from or transmitted through the tissue of the user, wherein the first wavelength is in a range of 370 nm to 410 nm; and
at least one processing circuit configured to:
determine a measurement value for a nitric oxide (NO) level in blood flow using the first PPG signal and the second PPG signal; and
determine an insulin response from caloric intake using the measurement value for the NO level in blood flow.
17. The biosensor of claim 16 , wherein the at least one processing circuit is further configured to determine a level of glucose in blood flow using the measurement value for the NO level in blood flow.
18. The biosensor of claim 17 , wherein the at least one processing circuit is further configured to determine a value R λ1,λ2 using the first PPG signal and the second PPG signal by:
determining a value L λ1 using the first PPG signal, wherein the value L λ1 isolates an alternating current (AC) component of the first PPG signal;
determining a value L λ2 using the second PPG signal, wherein the value L λ2 isolates an AC component of the second PPG signal; and
determining the value R λ1,λ2 from a ratio of the value L λ1 and the value L λ2 , wherein the value R λ1,λ2 is the measurement value for the NO level in blood flow.
19. The biosensor of claim 16 , wherein the at least one processing circuit is further configured to determine one or more phases of digestion using at least a third PPG signal of the plurality of PPG signals that is obtained from light at a third wavelength of approximately 592 nm reflected from or transmitted through the tissue of the user, wherein the phases of digestion include a phase 1 stage or a phase 2 stage.
20. The biosensor of claim 16 , wherein the at least one processing circuit is further configured to determine one or more phases of digestion using at least a third PPG signal by:
determining a value L λ3 using the third PPG signal, wherein the value L λ3 isolates an alternating current (AC) component of the third PPG signal;
determining a value L λ2 using the second PPG signal, wherein the value L λ2 isolates an AC component of the second PPG signal; and
determining a value R λ3,λ2 from a ratio of the value L λ3 and the value L λ2 , wherein the value R λ3,λ2 is used to determine one or more phases of digestion.