Patent Description:
It is known that an individual's aerobic power is normally defined in terms of maximum oxygen consumption: such parameter is also referred to as VO<NUM>max. The VO<NUM>max parameter is used, for example, in order to monitor cardiorespiratory adaptations to aerobic training programs, prescribe exercise intensity for aerobic training, and predict performance levels during resistance-based sports events.

It is also known that a direct measurement of an individual's expired gas samples provides highly reliable and accurate data, and is therefore considered to be the "gold standard", i.e. the most accurate diagnostic test for determining the VO<NUM>max parameter of an individual.

In particular, the gold standard used for detecting the VO<NUM>max parameter, among others, is undoubtedly the cardiopulmonary stress test.

Very often, however, this test is only available for selected individuals, in particular professional athletes or patients affected by particular disorders, because it requires costly equipment and qualified personnel.

As a consequence, many equations have been developed for estimating the VO<NUM>max parameter, which utilize different variables such as, for example, sex, age, height, weight, time of execution of a walk or a run on a treadmill and power thus generated, and so forth.

Such equations have been defined for various reference populations, including for instance men, women, teenager athletes, university students, elderly people, etc. One example of such equations can be found in the article by <NPL>. Such equations are necessarily inaccurate because, of course, they cannot precisely measure the VO<NUM>max parameter of every single individual. Instead, they estimate it on the basis of rough hypotheses assigning the individual to a given reference population.

Wearable garments are also commercially available, in particular chest belts, which are used, in particular, by people practising sports, whether at amateur or professional level, and measure a person's heart rate.

Such garments derive the ventilatory and metabolic parameter (VO<NUM>max) from the heart rate. However, they do not provide reliable data, in comparison with the "gold standard" of the cardiopulmonary stress test.

More in detail, in the sports world many resources have been dedicated by professionals, in particular sport physicians and scientists, to evaluating the various aspects of physical response to exercise, with particular reference to muscular force, power, maximum achievable speed and aerobic and anaerobic effort phases; not much attention has been paid to ventilatory response to exercise.

In many studies, cardiorespiratory response to exercise has been used essentially for finding the VO<NUM>max and anaerobic threshold values.

Training systems have also evolved over time with the advent of GPS, but they are still essentially based solely on cardiac response to exercise.

For example, metabolic power (postulated by comparing the sprint of a soccer player to an uphill run) extrapolates from the GPS data the athlete's energetic expenditure (GPEXE); or chest belts estimate, through suitable software, the VO<NUM>max parameter from the heart rate: see, in this regard, the article by <NPL>.

An article available on the Internet webpage https://www. com/wp-content/uploads/<NUM>/<NUM>/white_paper_vo2_estimation. pdf suggests the inaccuracy of the respiratory data obtained from chest belts, since it cannot be measured directly.

One of the inventors of the present patent application has executed approximately <NUM>,<NUM> cardiopulmonary stress tests on national and international professional athletes, publishing two scientific papers highlighting that ventilatory response and efficiency to exercise are ineluctable elements for the evaluation of the athletic performance of such athletes (see articles by <NPL>; <NPL>).

Document <CIT> relates to a method for providing an approximation of a minimum heart rate from collected heart rate data of a user. The method comprises calculating, from heartbeat signal collected from a user, a heart rate value and an artefact percentage for one or more time periods of the collected heartbeat signal and qualifying data of the time period(s) for which the user is verified to be awake and immobile, and for which the artefact percentage is under a predetermined value. Data of the other time periods is disqualified. The method further comprises calculating heart rate parameters from the qualified data and applying a function to the heart rate parameters in order to obtain the approximation of minimum heart rate.

Document <CIT> describes a respiratory analyzer comprising a flow module, having a flow tube through which the flow rate of gases is determined using a flow rate meter, and a computation module, in communication with the flow module, operable to determine a flow rate of respired gases. The computation module may also be operable to determine a metabolic rate of the subject.

Document <CIT> describes a filter to cut at least a harmonic component of a frequency component derived from breathing of a person to be observed which is applied to a detected signal of a wireless sensor, and a heartbeat component of the person is detected in a signal having passed through the filter.

Document <CIT> relates to a method for simultaneously measuring a respiration rate and a heart rate using dual cameras of a smartphone. The method includes: collecting a PPG signal and visual data on chest and abdomen movements of a human; converting the visual data to an RGBA signal; applying a bandpass filter such that a frequency only within a range in the RGBA signal pass; removing first and last predetermined portions of the RGBA signal to which the band-pass filter is applied; selecting a color channel having a highest standard deviation from the RGBA signal where the predetermined portions are removed; applying a spline filter to the selected color channel; computing power spectrum density; and computing a heart rate and a respiration rate.

The article in the name of <NPL>, develops and verifies methods required to predict and investigate the VO2 dynamics during activities of daily living. Variables derived from wearable sensors are used to create a VO2 predictor based on a random forest method.

It is therefore one object of the present invention to provide a method for providing real-time information about the cardiac and/or respiratory performance of an individual, as well as an associated device.

It is a further object of the present invention to provide a method for providing real-time information about the cardiac and/or respiratory performance of an individual, which is suitable for professional and amateur athletes and also for simple sports enthusiasts.

In brief, the present invention envisages a first embodiment comprising a method divided into two phases.

During a first phase, a subject undergoes a cardiopulmonary stress test in accordance with a given protocol, e.g. on a treadmill, and using a standard protocol (starting at <NUM>/h and increasing the speed by <NUM>/h per minute until physical exhaustion), for directly measuring the expired gases and volumes. Subsequently, a plurality of characteristic curves are obtained, which are mathematical functions that correlate the ventilatory and metabolic parameters of the individual with the respiratory rate only.

During a second phase of the method, such functions, which are univocally associated with the subject who has undergone the cardiopulmonary stress test, are used in an algorithm, e.g. implemented in an electronic device like, for example, a wearable device such as a smartwatch or a smartphone, or a tablet, an iPad, or even in cloud, for monitoring in real time the respiratory parameters of the individual and comparing them with his/her personal data obtained during the cardiopulmonary stress test, and then providing physiological indications, recommending physical exercises, predicting performance levels, and so forth.

This embodiment of the invention has been specially conceived for professional athletes (soccer players, cyclists, walkers, long-distance runners, etc.), who are regularly subjected to cardiopulmonary stress tests to obtain the authorization for competitive sport activities.

A second embodiment of the invention has been specially devised for non-professional and amateur athletes as well as simple sports enthusiasts.

More in detail, an individual who cannot or does not want to undergo a cardiopulmonary stress test, which, as aforesaid, is expensive and requires properly trained personnel to be executed, can nevertheless advantageously benefit from the results obtained from a plurality of other individuals who have carried out the cardiopulmonary stress test.

In fact, the data obtained from people who have undergone a cardiopulmonary stress test are collected into a special database.

An individual who cannot or does not want to undergo a cardiopulmonary stress test will have to wear a wearable garment, in particular a chest belt, and will repeat the same protocol, e.g. on a treadmill, as that which is used by people who carry out a cardiopulmonary stress test (e.g. starting at <NUM>/h and increasing the speed by <NUM>/h per minute until physical exhaustion); by measuring just the respiratory rate, the characteristic curves of a subject will be identified, among all the characteristic curves of people who underwent the cardiopulmonary stress test, which approximate most closely the characteristic curves of the individual. This search will be assisted by using anthropometric data of the various subjects, in particular sex, height, weight and age, in order to create some sort of initial division of the same into different groups. Once the reference characteristic curves have been identified, they will be implemented in memory means of the chest belt worn by the non-professional, amateur or enthusiast athlete for monitoring in real time his/her performance, recommending exercises, etc..

A substantial advantage of the method according to the invention lies in the fact that the functions developed by means of the gold standard provide an accurate profile in terms of ventilatory and metabolic cardiac response, whereas with only the heart rate and respiratory rate it would not be possible to extrapolate the aspect related to ventilation and to the metabolic component.

Further advantageous features of the present invention will be set out in the appended claims.

Further features and advantages of the present invention will become more apparent from the following description of an embodiment thereof as shown in the annexed drawings, which are supplied merely by way of non-limiting example, wherein:.

With reference to <FIG>, there is shown a flow chart <NUM> of a method for providing real-time information about the cardiac and/or respiratory performance of an individual compared with personal data of the same individual formerly obtained.

At step <NUM>, a subject starts a cardiopulmonary stress test in accordance with a given protocol, e.g. on a treadmill using a standard protocol (starting at <NUM>/h and increasing the speed by <NUM>/h per minute until physical exhaustion). Of course, the test may be carried out by using different means, e.g. a bicycle ergometer, and by following protocols other than said standard protocol.

The subject is connected to an electrocardiograph and, by means of a mouthpiece or a mask, to a breath detector that measures the air volumes taken in at each respiratory action, and to an analyzer that analyzes the gases (carbon dioxide and oxygen) that are exchanged at alveolus level. All the data collected during the exercise are processed by dedicated software, which provides a set of characteristic curves representing the individual adaptation to exercise in terms of ventilation and metabolism.

At step <NUM>, a suitable apparatus known in the art directly measures a number of cardiac or respiratory parameters, an extract of which is shown by way of example in <FIG>.

The parameters that are typically measured during a cardiopulmonary stress test are:.

At step <NUM>, the individual ends the cardiopulmonary stress test.

At step <NUM>, these parameters are recorded into a database.

At step <NUM>, by using the values entered into the database, one or more characteristic curves, or mathematical functions, are calculated which include only the respiratory rate as dependent variable and, as independent variables, ventilation, current volume, maximum oxygen consumption, maximum carbon dioxide consumption, end-expiratory partial oxygen pressure and end-expiratory partial carbon dioxide pressure.

Such functions are, preferably, second-degree polynomial functions obtained through a second-degree polynomial fitting of the measured values.

Such functions make it possible to obtain the subject's ventilatory and metabolic parameters starting from the subject's respiratory rate alone.

By way of example, ventilation VE can be obtained through the parameters a, b, c obtained from the respiratory rate FREQ. RESP alone, by applying the data obtained from the cardiopulmonary stress test to the formula: <MAT> where a, b, c are unknown parameters that characterize the characteristic curve of ventilation VE.

By so doing, a single ventilation value will be obtained for a given respiratory rate, such value representing a sort of mean ventilation value of all values detected in the subject during the cardiopulmonary stress test.

In another embodiment, such functions are, preferably, third-degree polynomial functions obtained through a third-degree polynomial fitting of the measured values.

By way of example, as shown in <FIG>, ventilation VE can be obtained through the parameters a, b, c, d obtained from the respiratory rate FREQ. RESP, by applying the data obtained from the cardiopulmonary stress test to the formula: <MAT>.

In the example shown herein, the curve <NUM> showing an increasing trend with moderate peaks is the curve measured during the cardiopulmonary stress test, while the curve <NUM> showing more pronounced peaks is the one approximated by the cubic function represented in the Figure by using the formula (<NUM>).

Still by way of example, as shown in <FIG>, the maximum oxygen consumption VO<NUM> can be obtained through the parameters a, b, c, d obtained from the respiratory rate FREQ. RESP, by applying the data obtained from the cardiopulmonary stress test to the formula: <MAT>.

Referring back to <FIG>, at step <NUM> the characteristic curves, or mathematical functions, obtained at step <NUM> are used in an algorithm, e.g. implemented in an electronic device like, for example, a wearable device such as a smartwatch or a smartphone, or a tablet, an iPad, or a wearable garment comprising memory means, or even in cloud, for monitoring in real time the respiratory parameters of the individual and comparing them with his/her personal data obtained during the cardiopulmonary stress test, and then providing physiological indications, recommending physical exercises, predicting performance levels, and so forth.

The electronic device generally comprises a display, and possibly a graphic interface, for providing visual indications to the user. It may also comprise audible signalling means for providing the user with other types of messages and/or alarms and/or indications.

With reference to <FIG>, there is shown a block diagram of a wearable garment <NUM> according to the present invention.

In order to monitor in real time the athletic performance of a subject, in particular an athlete, he/she will have to wear the wearable garment <NUM> comprising means <NUM> for measuring at least his/her respiratory rate.

Preferably, the wearable device is a chest belt.

Even more preferably, the wearable device <NUM> is a chest belt that measures the subject's respiratory rate via means adapted to detect the extension of the material, e.g. a fabric, it is made of. Chest belts of this kind are known, for example, from patent documents no. <CIT>, <CIT> and <CIT>.

The wearable garment <NUM> further comprises at least:.

Typically, such characteristic curves are transmitted to the wearable garment <NUM> from the database via the data transceiving module <NUM>.

The wearable device may further comprise one or more of the following modules:.

By measuring only the respiratory rate via the wearable garment <NUM>, the subject, in particular an athlete, will be able to monitor, via his/her heart rate, for example, ventilation and maximum oxygen consumption, as well as the evolution of his/her training path, observing in real time his/her improvements (or regressions) as a function of the trend of such current values.

For example, the effort being equal, the subject will be able to compare the values and define a strategy to improve a (ventilatory/metabolic or cardiac) quality and calibrate his/her work based on the accuracy bound to the ventilatory and metabolic datum, i.e. maximum oxygen consumption.

With reference to <FIG>, there is shown a flow chart <NUM> of a method for providing real-time information about the cardiac and/or respiratory performance of an individual compared with personal data of subjects who have already undergone a cardiopulmonary stress test following the same steps <NUM>, <NUM>, <NUM>, <NUM> and <NUM> illustrated herein with reference to the method of <FIG>. In this second embodiment, the database contains values derived from cardiopulmonary stress tests carried out by a plurality of subjects. For the purposes of the method of the invention, the larger the number of tests stored in the database, the greater the effectiveness of the method.

This second embodiment of the method according to the invention has been specially devised for non-professional and amateur athletes as well as simple sports enthusiasts.

At step <NUM>, an individual who cannot or does not want to undergo a cardiopulmonary stress test wears a wearable device comprising means adapted to detect his/her respiratory rate. It is known, in fact, as already mentioned, that for the execution of a cardiopulmonary stress test it is necessary to employ costly equipment and qualified personnel.

At step <NUM>, the individual, by using the same protocol illustrated at step <NUM>, carries out a dynamic test by running on a treadmill or pedalling on a bicycle ergometer or other similar means. It is essential, for the proper application of this embodiment of the method, that the protocol followed by the individual is the same as that which was used by the subjects who underwent the cardiopulmonary stress test according to steps <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, illustrated herein with reference to the method of <FIG>. Therefore, if the protocol required, for instance, starting at <NUM>/h and increasing the speed by <NUM>/h per minute until physical exhaustion, the individual will have to replicate the same protocol during the stress test.

At step <NUM>, the respiratory rate detected by the wearable device worn by the individual is stored into suitable memory means of the same device and/or communicated to an external recorder.

The equipment necessary for the stress test of steps <NUM>-<NUM> is advantageously minimal and not very expensive: as a matter of fact, a treadmill (or a bicycle ergometer) and a wearable device detecting the individual's respiratory rate will suffice. Therefore, the test can be carried out without an electrocardiograph, a mask with a mouthpiece, or qualified personnel. The test can even be carried out in a domestic environment, so long as the individual knows the protocol to be followed.

At step <NUM>, the individual ends the motor activity envisaged by the protocol.

At step <NUM>, the respiratory rate detected by the wearable device is transmitted to a cloud, where it is then compared with the values stored in the database, which contains the respiratory values of individuals who have carried out a cardiopulmonary stress test.

At step <NUM>, the functions of a subject are identified, among those contained in the database, which approximate most closely the respiratory values of the individual who has carried out the test at step <NUM>, possibly also taking into account anthropometric data of that subject, in particular sex, height, weight and age.

The functions can be chosen by using statistical techniques (e.g. the least residual or highest verisimilitude techniques) or machine learning techniques (e.g. the K-Means algorithm or neural networks).

At step <NUM>, the curve obtained at step <NUM> is transmitted to the wearable garment <NUM> and used in an algorithm, e.g. implemented in an electronic device like, in particular a wearable device such as a smartwatch or a smartphone, or a tablet, an iPad, or even in cloud, for monitoring in real time the current respiratory and/or cardiac parameters of the individual and providing physiological indications, recommending physical exercises, predicting performance, and so forth.

Advantageously, therefore, the individual who has not undergone an expensive cardiopulmonary stress test will be able to benefit from accurate data of subjects who carried out the cardiopulmonary stress test, which is considered to be the gold standard.

The method for providing real-time information about the cardiac and/or respiratory performance of an individual, and the associated device, described herein by way of example may be subject to many possible variations without departing from the novelty spirit of the inventive idea; it is also clear that in the practical implementation of the invention the illustrated details may have different shapes or be replaced with other technically equivalent elements.

For example, the invention also relates to a system comprising a wearable garment <NUM>, in which the individual's characteristic curves are stored, and an electronic device, in particular a smartwatch, a smartphone, a tablet, an iPad or a cloud, which suitably communicates with such wearable garment <NUM> to provide real-time information about the cardiac and/or respiratory performance of the individual wearing the garment <NUM>.

As an alternative, the system comprises a wearable garment that simply measures the respiratory rate of the individual and communicates with an electronic device worn by the user, in particular a smartwatch or a smartphone, in which the characteristic curves are stored.

Claim 1:
Method for providing real-time information about the cardiac and/or respiratory performance of an individual, comprising the steps of:
a) subjecting said individual to a cardiopulmonary stress test suitable for detecting, over time, a respiratory rate and other cardiac or respiratory parameters of said individual;
b) determining respective characteristic curves of said individual, with said respiratory rate as dependent variable and one of said other cardiac or respiratory parameters as independent variable;
c) measuring, through a wearable device, the current respiratory rate of said individual;
d) determining, based on the current respiratory rate of said individual and said characteristic curves obtained at step b), the other current cardiac or respiratory parameters of said individual;
e) providing real-time information about the cardiac and/or respiratory performance of said individual on the basis of the other current cardiac or respiratory parameters determined at step d).