NL2014046B1

NL2014046B1 - Method and device for determining a physical activity state of a human.

Info

Publication number: NL2014046B1
Application number: NL2014046A
Authority: NL
Inventors: Cornelis Hendricus De Kuijer Oskar
Original assignee: Vital B V
Priority date: 2014-12-23
Filing date: 2014-12-23
Publication date: 2016-10-12

Abstract

A method and device are provided for determining a physical activity state of a human. The method comprises receiving a signal representing a heartbeat of the human as a function of time. Based on that signal, multiple heartbeat rates at multiple points in time are determined. Based on the determined heartbeat rates, a first variability rate of the heartbeat rates over time is determined. If the first variability of the heartbeat rates decreases below a pre-determined level, it is determined that the body of the human moves from a first activity state to a second activity state. This method provides a more accurate determination of crossing the aerobic threshold than using the theories available and employing the formulas they provide. The analysis provides an output that depends on the state of the specific monitored body at that very moment.

Description

METHOD AND DEVICE FOR DETERMINING A PHYSICAL ACTIVITY STATE OF A HUMAN

TECHNICAL FIELD

The various aspects relate to the field of analysis of biometric data and the field of analysis of a exercise state of a human in particular.

BACKGROUND

To improve the condition of a physical body of a human body, combination of physical exercise and relaxation may be performed. Depending on how the condition of the body is to be improved, exercise if preferably executed at a specific state. Endurance training and cardio training are preferably executed between the aerobic and anaerobic thresholds. To properly and accurately determine that the body exercises between these thresholds, blood analysis or analysis of gases exhaled by the person doing the work out is required. This requires expensive equipment which in turn needs to be connected to the human body in question - which may hamper proper movement of the body.

Theories exist to couple the aerobic and anaerobic threshold to a specific heartbeat. Such theories provide generalised formulas, like the Haskell and Fox formula. However, human bodies are very different and a trained body may reach for example the aerobic area, the anaerobic area and the V02 max area at different heartbeats than an untrained body. And from day tot day there may be significant changes in these thresholds.

SUMMARY A more accurate way of determining a physical state of a body of a human is preferred. A first aspect provides a method of determining a physical activity state of a human. The method comprises receiving a heartbeat signal representing a heartbeat of the human as a function of time and based on that signal, multiple heartbeat rates at multiple points in time are determined. Based on the determined heartbeat rates, at least a first variability rate of the heartbeat rates over time is determined and if the first variability of the heartbeat rates decreases below a pre-determined level, it is determined that the body of the human moves from a first activity state to a second activity state. Or if the first variability of the heartbeat rates increases above a second pre-determined level, it is determined that the body of the human moves from the second activity state to the first activity state.

This method provides a more accurate determination of crossing the aerobic or anaerobic threshold than using the theories available and employing the formulas they provide. The analysis provides an output that depends on the state of the specific monitored body at that very moment.

An embodiment of the first aspect comprises determining, over time, multiple variability rates of the heart beat rates and monitoring change of values of the variability rates over time. If the change of the values of the variability rates changes by more than a first predetermined value over a first pre-determ ined amount of time, it is determined that the body of the human moves from the first activity state to the second activity state. Or if the change of the values of the variability rates changes by more than a second predetermined value over a second pre-determ ined amount of time, it is determined that the body of the human moves from the second activity state to the first activity state.

Monitoring a specific drop of heartbeat variability provides an even more accurate indication of reaching or crossing the aerobic or anaerobic threshold. Heartbeat rates may vary over time anyway and a significant drop over time may indicate a specific event. The first pre-determ ined value may be equal to the second pre-determ ined value and the first pre-determ ined amount of time may be equal to the second pre-determ ined amount of time.

Another embodiment of the first aspect comprises obtaining data on a breathing rate of the human as a function over time and determining that the body of the human moves from the first activity state to the second activity state, if the breathing rate increases over time by more than a third pre-determ ined value over a third pre-determ ined amount of time or that the body of the human moves from the second activity state to the first activity state if the breathing rate decreases over time by more than a fourth predetermined value over a fourth pre-determ ined amount of time.

Monitoring breathing rate next to the heartrate time provides an additional parameter for finding the transition from the first activity state to the second activity state. The breathing rate may be directly measured or derived from another measured or derived signal. The third pre-determined value may be equal to the fourth pre-determined value and the third pre-determ ined amount of time may be equal to the fourth pre-determ ined amount of time.

Yet a further embodiment of the first aspect comprises upon determination that the body of the human moves from the first activity state to the second activity state, storing a transition heart beat rate determined at the transition from the first activity state to the second activity state.

The actual heartbeat rate at which the body of the person involved reaches or crosses the aerobic or anaerobic threshold are important values. As indicated, such heartbeat rate may be determined using theoretical formulas already available, but using the method according to the first aspect, this may be done more accurate, without requiring a significant amount of equipment. A second aspect provides a method of providing a training session to a human, comprising providing an exercise to the human by providing a pre-determ ined workload for physical exercise of the body of the human, increasing the workload from a first predetermined level to a second pre-determ ined level; and the method according to the first aspect or embodiments thereof for determining a physical activity state of a human.

The exercise provided may be a full workout, with steadily increasing workload, until various pre-defined stages of activity states have been determined, from for example rest state up to V02max. Such exercise may be very tiring to a human, which may have as a result that the human is not capable anymore of performing a regular training. Alternatively, the exercise is a warming up comprising 4 minutes at a heartbeat frequency between 70 and 120 beats per minute, two minute between 100 and 130 and two minutes above 130. Generally, a warning up may - among others - be used to reaching an aerobic state. Alternatively the exercise is just starting without a defined script. A third aspect provides a device for determining a physical activity state of a human, the device comprising a communication module for receiving a heartbeat signal representing a heartbeat of the human as a function of time; and a processing unit. The processing unit is arranged to determine, based on the received heartbeat signal, multiple instantaneous heartbeat rates at multiple points in time, determine, based on the determined heartbeat rates, at least a first variability rate of the heartbeat rates over time; and determine that the body of the human moves from a first activity state to a second activity state, if the first variability of the heartbeat rates decreases below a predetermined level or that the body of the human moves from the second activity state to the first activity state if the first variability of the heartbeat rates increases above a second pre-determined level. A fourth aspect provides a device for providing a training session to a human, comprising a load module arranged to provide a pre-determ ined workload for physical exercise of the body of the human, a load control module arranged to increasing the workload from a first pre-determ ined level to a second pre-determ ined level; and a device according to the third aspect. A fifth aspect provides a computer programme product comprising computer executable instruction loadable in a processor causing the processor to execute the method according to the first aspect or embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects and embodiments will now be discussed in further detail in conjunction with Figures. In the Figures,

Figure 1: shows a system comprising a smartphone, a treadmill and a remote server;

Figure 2: shows a flowchart depicting a procedure;

Figure 3: shows a first graph; and Figure 4: shows a second graph.

DETAILED DESCRIPTION

Figure 1 shows a smartphone 100 for processing and / or storage of signal data. The smartphone 100 comprises a microprocessor 102 as a processing unit for controlling the various components of the smartphone 100, a flash memory 104 as a memory module for storing data, a data communication module 106 arranged for data exchange with local devices, a radio communication module 108 as a network communication module for communicating with remotely devices and a display 110. The flash memory 104 has data stored in it to enable the various components of the smartphone 100 and the microprocessor 102 in particular to execute the various methods as discussed below. Alternatively or additionally to flash, the memory module may also comprise other storage means like SRAM, DRAM or a harddisk. Alternatively to the smartphone 100, also a tablet computer, a laptop computer, a desktop computer, smartwatch of any other computing device may be used.

Figure 1 also shows a computer 122 acting as a data server located remotely from the smartphone 100 and connected to the smartphone 100 via a network 120. The network 120 is arranged to connect multiple computing devices with one another through wired and/or wireless connections. The computer 122 comprises a network communication module 124, a server microprocessor 126 as a server processing module and a harddisk or any other memory storage 128 as a server memory module.

The harddisk 128 has data stored in it to enable the various components of the computer 122 and the microprocessor 126 in particular to execute the various methods as discussed below. Alternatively or additionally to flash, the memory module may also comprise other storage means like SRAM, DRAM or flash.

Furthermore, Figure 1 shows a treadmill 140 connected to a treadmill driving module 142. The treadmill driving module 142 is connected to the smartphone 100 for the smartphone to control a workload provided by the treadmill to a person 150 who performs a workout on the treadmill 140. As an alternative to the treadmill 140, also a bike, hometrainer, step trainer, ergometer, other device or combination thereof may be used. The person 150 is provided with a sensor module 144 that is connected to the smartphone 100. The connections indicated in Figure 1 between the various components smartphone 100 on one hand and the treadmill 140 and the sensor module 144 on the other hand may be wired or wireless. A wireless connection is preferably established by means of radio communication, like Bluetooth or WiFi. The sensor module 144 is arranged to sense a heartbeat behaviour of the person 150 and/or breathing behaviour of the person 150. The heartbeat behaviour and the breathing behaviour of the person 150 are converted to signals representing such behaviour. The signals are provided to the smartphone 100.

The signal or signals thus received are processed by the microprocessor 102 of the smartphone. Alternatively or additionally, the signal or signals are communicated to the computer 122 for processing by the server microprocessor 126. The signal or signal may be processed and in case applicable, transmitted on a real time basis. Alternatively or additionally, the signal or signals are stored in the flash memory 104 or the harddisk 128 for later processing. After processing, processed data may be provided on the display 110.

Processing of data will now be discussed in conjunction with a flowchart 200 shown by Figure 2. Short summaries of the various steps of the flowchart 200 are provided in the list below. In the embodiments described below, the processing of received signals is provided by the microprocessor 102. The same or similar processing may also be performed by the server microprocessor 126. 202 Start procedure 214 Provide slowly increasing physical workload 221 Receive heartbeat signal 222 Determine heartbeat rate 226 Determine variability of heartbeat rate over time 228 Variability below pre-determined threshold? 230 Store heartbeat rate 232 End of workout? 242 Receive breathing rate signal 244 Determine breathing rate 246 Determine increase/decrease of heartbeat rate 248 Determine change of breathing rate over time 250 Increase above threshold? 252 Store heartbeat rate 254 End of workout? 280 End of procedure

The procedure depicted by the flowchart 200 starts in a terminator 202. Subsequently, a slowly and steadily increasing workout programme is provided to the human 150 in step 212. The workload is controlled by controlling the treadmill driving module 142. In the embodiment depicted, the treadmill driving module 142 is controlled by the smartphone 100. Alternatively, the treadmill driving module 142 is controlled by another controlling device. In yet another alternative, the treadmill driving module 142 operates autonomously or is controlled directly by means of a user input devices provided on the treadmill driving module 142, like a knob, switch, or other provided with the treadmill 140.

Simultaneously, a heartbeat signal is received by means of the sensor module 144 and the data communication module 106 in step 222. In step 224, a heartbeat rate is determined based on information provided by the heartbeat signal. The heartbeat rate may be expressed as a time interval between two heartbeats. Alternatively or additionally, the heartbeat rate may be expressed as a frequency of heartbeats per time interval, for example per minute or per second. The heartbeat rate may be determined as an instantaneous value or as an average value over a certain time interval.

Having determined the heartbeat rate, variation of the heartbeat rate is determined in step 226. The variation of the heartbeat rate may be determined in various ways. The standard deviation may be determined, the amplitude of the heartbeat rates over time as a top-top value or as an average - top value or in another way. In step 228 is checked whether the variation of the heartbeat rate over time drops below a heartbeat variation threshold value. The heartbeat variation threshold value may be predetermined. Alternatively, the heartbeat variation threshold value is determined as a percentage of the heartbeat rate variation determined at the start of a workout. Upon determining that the heart beat rate variation drops below the heartbeat variation threshold value, it may be determined that the body of the person 150 has reached or crosses the aerobic threshold. Alternatively or additionally, a specific drop - either relative or absolute - of the heartbeat rate is determined over a specific, preferably predetermined, amount of time. If the drop over a specific amount of time exceeds a relative drop threshold, it may also be determined that the body of the person 150 has reached or crosses the aerobic threshold.

The state the body of the body after crossing the aerobic threshold is preferred for an endurance workout. When is it determined that the body of the person 150 has reached or crosses the aerobic threshold, an aerobic threshold heartbeat rate determined at the moment of reaching or crossing the aerobic threshold is stored in step 230. This indicated in Figure 3. Figure 3 shows a first graph 300 depicting the heartbeat rate of the person 150 as a function in time, with a steadily increasing workout being provided to the person 150. In the first graph 300, a continuous line 302 shows a heartbeat rate value over time. A dashed line 304 indicates a breathing rate over time. A first dotted line 306 indicates a point in time at which the aerobic threshold is reached and crossed. The heartbeat rate stored in step 230 may serve as a lower heartbeat threshold for a heartbeat range at which a workout is provided.

Flaving stored the heartbeat rate at which the aerobic threshold is reached or crossed, it is checked whether an end of the procedure is requested or required in step 232. If this is the case, the procedure comes to an end in a terminator 280. If this is not the case, the procedure jumps back to the first step 222. Also if in step 228 dropping of the variation of the heartbeat has not dropped below a specific value, the procedure jumps back to the first step 222.

Alternatively or additionally to obtaining the heartbeat signal, a breathing signal is retrieved in step 242, following start of the procedure. Subsequently, based on the breathing signal representing breathing behaviour of the person 150, the breathing rate is determined. This is preferably done by determining an inhaling time period during which the person 150 inhales and an exhaling time period during which the person 150 exhales. A total breathing period is subsequently determined by adding the inhaling time period to the exhaling time period. Based on the total breathing period, a breathing frequency or breathing rate may be determined in step 244. Alternatively or additionally, also other methods may be employed. For example, a time interval between starting of inhaling is determined or a time interval between a transition between inhaling and exhaling or between exhaling and inhaling is determined. Based on such time interval, a breathing frequency may be determined.

Alternatively or additionally, the breathing rate may be determined from the heartbeat rate. It is known that when a person inhales, his or her heartbeat rate becomes smaller. And when that person exhales, the heartbeat rate becomes larger. So also in an aerobic exercise state of the body of the person 150, the heartbeat rate varies. However, the variation of the heartbeat rate is smaller than in a resting state when the exercise is started. In step 246 is determined whether the heartbeat rate determined in step 224 increases or decreases. Figure 4 shows a second graph 400 with heartbeat rate over time. The curve 402 connects various values of heartbeat rate. The dotted lines delimit intervals in which the heartbeat rate increases and decreases. This information provided by step 246 may be provided as input to step 244 as well for determining a breathing rate. The determined breathing rate is indicated by the dashed line 404. The average heartbeat rate as provided in the second graph 400 is drawn to be constant. In at least most practical cases, the average heartbeat rate will increase over time as the workload provided to the person 150 increases as well.

At the moment it is in step 250 determined that increase of the heartbeat rate over time is such that the aerobic threshold is crossed, the procedure continues to step 252 by storing an aerobic threshold heartbeat rate value which the heartbeat rate has at the moment the aerobic threshold is reached or crossed. Subsequently, it is checked whether the procedure has come to an end in step 254. If this is the case, the procedure continues to the terminator 280. If the procedure has not come to an end the procedure jumps back to step 242. It is stipulated that in this way, the left and right chain of steps may be executed as alternatives as well as complements, with the left chain executed via step 246 or step 242 or both step 246 or step 242.

Additionally or alternatively, also a heartbeat rate at which the anaerobic threshold is reached may be determined. This may be done by monitoring the heart rate variability and / or the breathing rate. As indicated above and in Figure 3, the breathing frequency increases over time as the person 150 is provided with a workload that is steadily and gradually increasing over time - and the person has crossed the aerobic threshold. While the person 150 is in the aerobic state, the breathing rate is still monitored to check for further increase of the breathing rate over time. If the breathing rate increase over a pre-determined interval more than before, it is determined the person 150 has reached or crossed the anaerobic threshold and the body of the person 150 is in anaerobic state. This is indicated in Figure 3 by the second dotted line 310. At the moment the person 150 reaches or crosses this threshold, an anaerobic threshold heartbeat rate is determined and stored.

Having determined the aerobic threshold heartbeat rate and the anaerobic threshold heartbeat rate, a heartbeat rate interval between these two values may be determined in which the person 150 may be provided an endurance training programme by means of the treadmill 140. This is done by controlling the treadmill driving module 142 such that the treadmill 140 provides a workload to the person 150 such that the heartbeat rate of the person remains and preferably varies between the aerobic threshold heartbeat rate and the anaerobic threshold heartbeat rate.

The aerobic threshold heartbeat rate and the anaerobic threshold heartbeat rate may also be used in a graphical user interface for providing the person 150 feedback on an exercise programme. The graphical user interface may be presented on the display 110 (Figure 1). The person 150 may be provided with information on having passed the aerobic threshold or not, on the instantaneous heartbeat rate of the person, preferably relative to the aerobic threshold heartbeat rate and the anaerobic threshold heartbeat rate. Also other determined values may be presented to the user via the display 110.

Various variations on the embodiments disclosed above are possible. As already indicated, processing of data signal representing heartbeat and/or breathing of a person may be executed locally or remotely, in "the cloud". In the latter scenario, processed data is subsequently sent back to the local device. Furthermore, the treadmill driving module 142 may be controlled by the smartphone 100 for providing a training programme or, alternatively, increase or decrease workload provided autonomously. Instead of the treadmill 140, also other exercising devices like a bike, home-trainer, a cross-trainer, a step-trainer, other, or a combination thereof may be used. The local processing and acquisition of data is in the embodiments above performed by the smartphone 100. However, such functionality may also be provided by a controlling circuit incorporated in the exercising equipment.

Expressions such as "comprise", "include", "incorporate", "contain", "is" and "have" are to be construed in a non-exclusive manner when interpreting the description and its associated claims, namely construed to allow for other items or components which are not explicitly defined also to be present. Reference to the singular is also to be construed in be a reference to the plural and vice versa.

In the description above, it will be understood that when an element such as layer, region or substrate is referred to as being "on", "onto" or "connected to" another element, the element is either directly on or connected to the other element, or intervening elements may also be present.

Furthermore, the invention may also be embodied with less components than provided in the embodiments described here, wherein one component carries out multiple functions. Just as well may the invention be embodied using more elements than depicted in Figure 1, wherein functions carried out by one component in the embodiment provided are distributed over multiple components. A person skilled in the art will readily appreciate that various parameters disclosed in the description may be modified and that various embodiments disclosed and/or claimed may be combined without departing from the scope of the invention.

It is stipulated that the reference signs in the claims do not limit the scope of the claims, but are merely inserted to enhance the legibility of the claims.

Claims

A method for determining a physical state of a human, comprising: Receiving a heartbeat signal representing a heartbeat activity of a people as a function of time; Based on the received heart rate signal, determining multiple heart rate values at multiple points in time; Based on the determined heart rate values, determining at least a first variation of the heart rate values over time; Determining that the body of the people is from a first activity to a second activity goes if the first variation of the heart rate decreases below a first predetermined level or that the body of the people is from the second activity to the first activity when the first variation of heart rate values rises above a second predetermined level.

The method of claim 1, further comprising: Determining, over time, different variation values of heart rate values; Determining change of values of the variation values over time; Determining that the body of the people is from the first activity state to the second activity state if the change of the values of the variation values changes by more than a first predetermined value over a first predetermined period of time or that the body of the people of the second activity state goes to the first activity state when the change of the values of the variation values changes by more than a second predetermined value over a second predetermined period of time.

The method of any one of the preceding claims, further comprising: Obtaining data about a respiration rate of the people as a function over time; Determining that the human body moves from the first activity state to the second activity state when the respiration rate increases over time by more than a third predetermined value over a third predetermined period of time or that the human body moves from the second activity state to the first activity state goes as the respiration rate decreases over time by more than a fourth predetermined value over a fourth predetermined duration.

The method of claim 3, further comprising: Obtaining data regarding a respiration rate over time; Determine that the human body is from the second activity state to a third activity state when the respiration rate increases over time by more than a fifth predetermined value over a fifth predetermined amount of time and that the human is in the second activity or that the human body is from the third activity state to the second activity state when the respiration rate goes down by more than a sixth predetermined value over a sixth predetermined period of time and the body is in the third activity.

The method of claim 4, wherein the third activity state is an anearobic state.

The method of claim 3 or 4, further comprising receiving a respiratory signal which represents human respiratory behavior as a function over time and wherein obtaining a respiratory signal comprises acquiring respiratory rate data from the respiratory signal.

A method according to any one of the preceding claims, further comprising after determining that the human body goes from the first activity state to the second activity, storing a transition heart rate value determined at the transition from the first activity state to the second activity state.

The method of claim 7, further comprising displaying the determined heart rate value and second transition heart rate value on a screen.

The method of any one of the preceding claims, wherein the second activity state is an aerobic state.

A method for delivering a training session to a human, comprising: Delivering an exercise to a human by providing a predetermined workload for physical exertion of the human body; Increasing the workload from a first predetermined level to a second predetermined level; The method according to any of the preceding claims for determining a physical activity state of man.

A device for determining a physical activity state of a human, the device comprising: A communication module for receiving a heartbeat signal representing a heartbeat activity of a people as a function of time; and a processing unit configured for: Based on the received heart rate signal, determining multiple heart rate values at multiple times in time; Based on the determined heart rate values, determining at least a first variation of the heart rate values over time; Determining that the body of the people is from a first activity to a second activity goes when the first variation of the heart rate decreases below a first predetermined level or that the body of the people is from the second activity to the first activity state when the first variation of heart rate values rises above a second predetermined level.

An apparatus for delivering training to a human, comprising: A load module adapted to provide a predetermined workload for physical exertion for the human body; A load control module designed to increase the workload from the first level to the second level; and The device of claim 11.

A computer program product comprising computer-executable instructions that can be loaded into a processing unit so that the processing unit can carry out the method according to any of claims 1 to 9.