Latent load calibration for calorimetry using sensor fusion
In one aspect, the present disclosure relates to a method including obtaining, by a heart rate sensor of a fitness tracking device, a heart rate measurement of a user of the fitness tracking device; obtaining, by at least one motion sensor, motion data of the user; analyzing, by the fitness tracking device, the motion data of the user to estimate a step rate of the user; estimating, by the fitness tracking device, a load associated with a physical activity of the user by comparing the heart rate measurement with the step rate of the user; and estimating, by the fitness tracking device, an energy expenditure rate of the user using the load and at least one of the heart rate measurement and the step rate.
1. A method comprising:
obtaining, by a heart rate sensor of a fitness tracking device, a heart rate measurement of a user of the fitness tracking device at a first sampling rate in response to determining that the user is in a particular activity session and at a second sampling rate at other times, wherein the first sampling rate is higher than the second sampling rate;
obtaining, by at least one motion sensor, motion data of the user;
analyzing, by the fitness tracking device, the motion data of the user to estimate a step rate of the user;
estimating, by the fitness tracking device, a load associated with a physical activity of the user by comparing the heart rate measurement with the step rate of the user; and
estimating, by the fitness tracking device, an energy expenditure rate of the user using a combination of the load and:
the heart rate measurement when the heart rate measurement is obtained at the first sampling rate, and
the step rate when the heart rate measurement is obtained at the second sampling rate.
2. The method of claim 1 , wherein the physical activity of the user comprises training on an elliptical training machine, and wherein the load comprises a resistance setting of the elliptical training machine.
3. The method of claim 1 , wherein the physical activity of the user comprises running on a treadmill, and wherein the load comprises an incline setting of the treadmill.
4. The method of claim 1 , wherein the physical activity of the user comprises stationary cycling, and wherein the load comprises a resistance setting of a stationary cycle.
5. The method of claim 1 , comprising:
analyzing, by the fitness tracking device, the motion data to determine a speed of the user,
wherein the physical activity of the user comprises running, and
wherein the load comprises a grade of a terrain on which the user comprises running.
6. The method of claim 1 , wherein a first heart rate measurement indicates a first load for a given step rate, and wherein a second heart rate measurement different from the first heart rate measurement indicates a second load for the given step rate different from the first load for the given step rate.
7. The method of claim 1 , wherein a first step rate indicates a first load for a given heart rate, and wherein a second step rate different from the first step rate indicates a second load for the given heart rate different from the first load for the given step rate.
8. A fitness tracking device comprising:
a heart rate sensor for measuring a heart rate of a user of the fitness tracking device at a first sampling rate in response to determining that the user is in a particular activity session and at a second sampling rate at other times, wherein the first sampling rate is higher than the second sampling rate;
a motion sensor for sensing motion of the user; and
a processor communicatively coupled to the heart rate sensor and the motion sensor, wherein the processor is configured to:
obtain a heart rate measurement of the user from the heart rate sensor;
obtain motion data of the user from the motion sensor;
analyze the motion data of the user to estimate a step rate of the user;
estimate a load associated with a physical activity of the user by comparing the heart rate measurement with the step rate of the user; and
estimate an energy expenditure rate of the user using a combination of the load and:
the heart rate measurement when the heart rate measurement is obtained at the first sampling rate, and
the step rate when the heart rate measurement is obtained at the second sampling rate.
9. The fitness tracking device of claim 8 , wherein the physical activity of the user comprises training on an elliptical training machine, and wherein the load comprises a resistance setting of the elliptical training machine.
10. The fitness tracking device of claim 8 , wherein the physical activity of the user comprises running on a treadmill, and wherein the load comprises an incline setting of the treadmill.
11. The fitness tracking device of claim 8 , wherein the physical activity of the user comprises stationary cycling, and wherein the load comprises a resistance setting of a stationary cycle.
12. The fitness tracking device of claim 8 , where the processor is configured to:
analyze the motion data to determine a speed of the user,
wherein the physical activity of the user comprises running, and
wherein the load comprises a grade of a terrain on which the user is running.
13. The fitness tracking device of claim 8 , wherein a first heart rate measurement indicates a first load for a given step rate, and wherein a second heart rate measurement different from the first heart rate measurement indicates a second load for the given step rate different from the first load for the given step rate.
14. The fitness tracking device of claim 8 , wherein a first step rate indicates a first load for a given heart rate, and wherein a second step rate different from the first step rate indicates a second load for the given heart rate different from the first load for the given step rate.
15. An article of manufacture comprising:
a non-transitory processor readable storage medium; and
instructions stored on the medium;
wherein the instructions are configured to be readable from the medium by a processor of a fitness tracking device comprising a heart rate sensor and a motion sensor and thereby cause the processor to operate to:
obtain a heart rate measurement of a user of the fitness tracking device from the heart rate sensor at a first sampling rate in response to determining that the user is in a particular activity session and at a second sampling rate at other times, wherein the first sampling rate is higher than the second sampling rate;
obtain motion data of the user of the fitness tracking device from the motion sensor;
analyze the motion data of the user to estimate a step rate of the user;
estimate a load associated with a physical activity of the user by comparing the heart rate measurement with the step rate of the user; and
estimate an energy expenditure rate of the user using a combination of the load and:
the heart rate measurement when the heart rate measurement is obtained at the first sampling rate, and
the step rate when the heart rate measurement is obtained at the second sampling rate.
16. The article of manufacture of claim 15 , wherein the physical activity of the user comprises training on an elliptical training machine, and wherein the load comprises a resistance setting of the elliptical training machine.
17. The article of manufacture of claim 15 , wherein the physical activity of the user comprises running on a treadmill, and wherein the load comprises an incline setting of the treadmill.
18. The article of manufacture of claim 15 , wherein the physical activity of the user comprises stationary cycling, and wherein the load comprises a resistance setting of a stationary cycle.
19. The article of manufacture of claim 15 , where the processor is caused to:
analyze the motion data to determine a speed of the user,
wherein the physical activity of the user comprises running, and
wherein the load comprises a grade of a terrain on which the user is running.
20. The article of manufacture of claim 15 , wherein a first heart rate measurement indicates a first load for a given step rate, and wherein a second heart rate measurement different from the first heart rate measurement indicates a second load for the given step rate different from the first load for the given step rate.