DEHYDRATION ESTIMATION DEVICE, ESTIMATION METHOD AND PROGRAM

1 - 8 . (canceled)

9 . A dehydration estimation device comprising:

one or more processors; and

a storage device storing a program to be executed by the one or more processors, the program including instructions for:

estimating a blood electrolyte concentration of a measurement subject; and

determining presence or absence of dehydration of the measurement subject on a basis of the blood electrolyte concentration.

10 . The dehydration estimation device according to claim 9 , wherein the program further includes instructions for:

measuring a sweat amount of the measurement subject; and

measuring a sweat electrolyte concentration of the measurement subject, wherein the blood electrolyte concentration is estimated on a basis of the sweat amount and the sweat electrolyte concentration.

11 . The dehydration estimation device according to claim 9 , wherein the program further includes instructions for:

measuring a sweat amount of the measurement subject; and

estimating a sweat electrolyte concentration of the measurement subject on a basis of the sweat amount, wherein the blood electrolyte concentration is estimated on a basis of the sweat amount and the sweat electrolyte concentration.

12 . The dehydration estimation device according to claim 9 , wherein the program further includes instructions for:

measuring a heart rate of the measurement subject;

measuring a temperature in a vicinity of the measurement subject;

measuring a humidity in a vicinity of the measurement subject;

estimating a sweat amount of the measurement subject on a basis of measurement results of the heart rate, the temperature, and the humidity; and

estimating a sweat electrolyte concentration of the measurement subject on a basis of the sweat amount, wherein the blood electrolyte concentration is estimated on a basis of the sweat amount and the sweat electrolyte concentration.

13 . The dehydration estimation device according to claim 12 , wherein the program further includes instructions for:

calculating an upper limit value of a normal range of water intake of the measurement subject on a basis of the sweat amount, the sweat electrolyte concentration, and the blood electrolyte concentration; and

predicting a transition of a future blood electrolyte concentration on a basis of the sweat amount, the sweat electrolyte concentration, and the blood electrolyte concentration, and estimate a time until the blood electrolyte concentration reaches the upper limit value of the normal range.

14 . The dehydration estimation device according to claim 13 , wherein

when the sweat amount is SW[t] and the sweat electrolyte concentration is C SW [t], intracellular fluid water amount V IC [t+Δt] is estimated at time t+Δt after Δt on a basis of an intracellular fluid water amount V IC [t] estimated immediately before for the measurement subject, estimates an extracellular fluid water mount V EC [t+Δt] at time t+Δt on a basis of an extracellular fluid water mount V EC [t] estimated immediately before for the measurement subject, the sweat amount SW[t], and a body surface area of the measurement subject, estimates an osmotic pressure C IC [t+Δt] of an intracellular fluid at time t+Δt on a basis of the intracellular fluid water amount V IC [t], an osmotic pressure C IC [t] of an intracellular fluid estimated immediately before for the measurement subject, and the intracellular fluid water amount V IC [t+Δt], and estimates a blood electrolyte concentration C EC [t+Δt] at time t+Δt on a basis of a blood electrolyte concentration C EC [t] estimated immediately before for the measurement subject, the extracellular fluid water mount V EC [t], the sweat electrolyte concentration C SW [t], the sweat amount SW[t], the body surface area, and the extracellular fluid water mount V EC [t+Δt].

15 . A method comprising:

measuring or estimating a sweat amount of a measurement subject;

measuring or estimating a sweat electrolyte concentration of the measurement subject;

estimating a blood electrolyte concentration of the measurement subject on a basis of the sweat amount and the sweat electrolyte concentration; and

determining presence or absence of dehydration of the measurement subject on a basis of the blood electrolyte concentration.

16 . A method for estimating dehydration, comprising:

measuring, by a sensor attached to a measurement subject, a sweat amount of the measurement subject;

measuring, by the sensor, an electrolyte concentration in sweat of the measurement subject;

storing time-series data of the sweat amount and the sweat electrolyte concentration;

estimating a blood electrolyte concentration of the measurement subject based on the time-series data of the sweat amount and the sweat electrolyte concentration; and

determining a dehydration state of the measurement subject based on the estimated blood electrolyte concentration.

17 . The method of claim 16 , wherein the sensor calculates the sweat amount of the measurement subject based on the characteristic of current application between electrodes of the sensor.

18 . The method of claim 16 , wherein the wearable sensor calculates the electrolyte concentration in sweat of the measurement subject based on light receiving characteristics of a light receiving element of the sensor.