Determining a health status for a user

1. A method for evaluating health of a user, comprising:

tracking a plurality of vital signs of a user using a plurality of sensors of a device, wherein the plurality of vital signs are determined from sensor data generated by the plurality of sensors;

storing an equilibrium envelope for the user in a memory of the device with the plurality of vital signs, wherein the equilibrium envelope includes a range for each of a plurality of vital signs for the user and historical metric data, wherein each range indicates homeostatic equilibrium for the user while at rest for one of the plurality of vital signs;

detecting, using a processor of the device in real-time, the user starting an activity based on the sensor data;

in response to detecting the activity, detecting, using the processor and based on the sensor data, an exit condition for a selected vital sign of the plurality of vital signs, wherein the exit condition is the selected vital sign exiting the range of the equilibrium envelope corresponding to the selected vital sign;

determining an amount of time for the exit condition to occur measured from a start of the activity; and

determining, using the processor, a health status for the user based upon the amount of time for the exit condition to occur for the selected vital sign compared to a historical amount of time for the exit condition to occur for the selected vital sign from the historical metric data of the equilibrium envelope.

2. The method of claim 1 , wherein the sensor data includes a photoplethysmogram.

3. The method of claim 1 , wherein the selected vital sign is heart rate.

4. The method of claim 1 , comprising:

determining an amount of work performed by the user from a time that the activity was detected to the exit condition; and

wherein the health status of the user is further based on the amount of work performed.

5. The method of claim 1 , comprising:

detecting a re-entry condition based on the sensor data, wherein the re-entry condition is, subsequent to the exit condition, the user discontinuing the activity while one or more of the plurality of vital signs is outside of the range for the vital sign per the equilibrium envelope and each vital sign of the plurality of vital signs entering the range for the vital sign.

6. The method of claim 5 , comprising:

determining an amount of time for the re-entry condition to occur after the user discontinues the activity; and

wherein the health status of the user is further based on the amount of time for the re-entry condition to occur.

7. The method of claim 1 , wherein the plurality of vital signs includes heart rate and blood pressure.

8. The method of claim 7 , wherein the plurality of vital signs further includes respiration rate.

9. The method of claim 8 , wherein the plurality of vital signs further includes heart rate variability, oxygen saturation, and blood glucose.

10. A device, comprising:

a memory configured to store instructions;

a plurality of sensors configured to collect sensor data for a user; and

a processor coupled to the memory, wherein the processor, in response to executing the instructions, is configured to initiate operations for evaluating health of the user including:

tracking a plurality of vital signs of the user using the plurality of sensors, wherein the plurality of vital signs are determined from sensor data generated by the plurality of sensors;

storing an equilibrium envelope for the user in the memory with the plurality of vital signs, wherein the equilibrium envelope includes a range for each of a plurality of vital signs for the user and historical metric data, wherein each range indicates homeostatic equilibrium for the user while at rest for one of the plurality of vital signs;

detecting, in real-time, the user starting an activity based on the sensor data;

in response to detecting the activity, detecting, based on the sensor data, an exit condition for a selected vital sign of the plurality of vital signs, wherein the exit condition is the selected vital sign exiting the range of the equilibrium envelope corresponding to the selected vital sign;

determining an amount of time for the exit condition to occur measured from a start of the activity; and

determining a health status for the user based upon the amount of time for the exit condition to occur for the selected vital sign compared to a historical amount of time for the exit condition to occur for the selected vital sign from the historical metric data of the equilibrium envelope.

11. The device of claim 10 , wherein the sensor data includes a photoplethysmogram.

12. The device of claim 10 , wherein the selected vital sign is heart rate.

13. The device of claim 10 , wherein the processor is configured to initiate operations comprising:

determining an amount of work performed by the user from a time that the activity was detected to the exit condition; and

wherein the health status of the user is further based on the amount of work performed.

14. The device of claim 10 , wherein the processor is configured to initiate operations comprising:

detecting a re-entry condition based on the sensor data, wherein the re-entry condition is, subsequent to the exit condition, the user discontinuing the activity while one or more of the plurality of vital signs is outside of the range for the vital sign per the equilibrium envelope and each vital sign of the plurality of vital signs entering the range for the vital sign.

15. The device of claim 14 , wherein the processor is configured to initiate operations comprising:

determining an amount of time for the re-entry condition to occur after the user discontinues the activity; and

wherein the health status of the user is further based on the amount of time for the re-entry condition to occur.

16. The device of claim 10 , wherein the plurality of vital signs includes heart rate and blood pressure.

17. The device of claim 16 , wherein the plurality of vital signs further includes respiration rate.

18. The device of claim 17 , wherein the plurality of vital signs further includes heart rate variability, oxygen saturation, and blood glucose.

19. A computer program product comprising a computer readable storage medium having program code stored thereon for evaluating health of a user, the program code executable by a processor to perform operations comprising:

tracking a plurality of vital signs of the user using a plurality of sensors of a device, wherein the plurality of vital signs are determined from sensor data generated by the plurality of sensors;

storing an equilibrium envelope for the user in a memory of the device with the plurality of vital signs, wherein the equilibrium envelope includes a range for each of a plurality of vital signs for the user and historical metric data, wherein each range indicates homeostatic equilibrium for the user while at rest for one of the plurality of vital signs;

detecting, using a processor of the device in real-time, the user starting an activity based on the sensor data;

in response to detecting the activity, detecting, based on the sensor data, an exit condition for a selected vital sign of the plurality of vital signs, wherein the exit condition is the selected vital sign exiting the range of the equilibrium envelope corresponding to the selected vital sign;

determining an amount of time for the exit condition to occur measured from a start of the activity; and

determining a health status for the user based upon the amount of time for the exit condition to occur for the selected vital sign compared to a historical amount of time for the exit condition to occur for the selected vital sign from the historical metric data of the equilibrium envelope.

20. The computer program product of claim 19 , wherein the sensor data includes a photoplethysmogram.

21. The computer program product of claim 19 , wherein the selected vital sign is heart rate.

22. The computer program product of claim 19 , wherein the program code is executable by a processor to perform operations comprising:

determining an amount of work performed by the user from a time that the activity was detected to the exit condition; and

wherein the health status of the user is further based on the amount of work performed.

23. The computer program product of claim 19 , wherein the program code is executable by a processor to perform operations comprising:

detecting a re-entry condition based on the sensor data, wherein the re-entry condition is, subsequent to the exit condition, the user discontinuing the activity while one or more of the plurality of vital signs is outside of the range for the vital sign per the equilibrium envelope and each vital sign of the plurality of vital signs entering the range for the vital sign.

24. The computer program product of claim 23 , wherein the program code is executable by a processor to perform operations comprising:

determining an amount of time for the re-entry condition to occur after the user discontinues the activity; and

wherein the health status of the user is further based on the amount of time for the re-entry condition to occur.

25. The computer program product of claim 19 , wherein the plurality of vital signs includes heart rate and blood pressure.

26. The computer program product of claim 25 , wherein the plurality of vital signs further includes respiration rate.

27. The computer program product of claim 26 , wherein the plurality of vital signs further includes heart rate variability, oxygen saturation, and blood glucose.