WO2007012818A1

WO2007012818A1 - Improvements in and relating to breath measurement

Info

Publication number: WO2007012818A1
Application number: PCT/GB2006/002704
Authority: WO
Inventors: Austen Peter Bradley
Original assignee: Nutren Technology Limited
Priority date: 2005-07-29
Filing date: 2006-07-20
Publication date: 2007-02-01
Also published as: GB0515607D0; EP1909646A1

Abstract

A calorimeter (2) comprising a means to determine the Energy of the metabolism of a user from one or more breaths of the user (20, 22), a means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath (24, 26), a means to detect a deviation from said reference breath in subsequent breaths of a user, and a means to adjust the recorded reference breath upon detection of a trend in deviation from the recorded reference breath in said subsequent breaths (24, 26).

Description

IMPROVEMENTS IN AND RELATING TO BREATH MEASUREMENT

Field of the Invention

This invention relates to breath monitoring apparatus and methods of monitoring breaths .

Background to the Invention

It is known to provide apparatus which measure a breathing parameter of a user's breath, and which displays the result of a measurement for a user, sports scientist or physician to review, for example.

In particular, devices are known for use in calorimetry, to study the energy of metabolism in humans and animals. Calorimetry is used, for example, for diagnosis of metabolic disorders and for calculating nutritional requirements of a subject. A useful calorimetric measure for nutritional and sports scientists, when assessing the health and fitness of a subject, is the volume of oxygen consumed at rest, and during or after physical exertion.

Indirect calorimetry often involves measuring the amount of carbon dioxide exhaled by a subject, which can in turn be used to calculate the oxygen consumption of a subject.

The measurement of the volume of oxygen consumed and/or the amount of carbon dioxide exhaled by a subject are normally measured as a single reading, at rest, during, or after physical exertion. Multiple measurements may be taken and plotted on a chart to indicate changes in oxygen and/or carbon dioxide measurement over a period of time.

In a known apparatus as described in applicant's published international application WO04/043254, an improvement to known calorimeters consists of a user first breathing into the calorimeter device to provide a reference, against which future breaths are compared. If a subsequent breath by the same user falls outside of a specified deviation from the reference, the calorimeter indicates to the user that a deviation has occurred, and the user then has the option to accept or decline the breath. The same calorimeter can also be used to detect when a user other than the original user utilises the calorimeter, as the second user' s breath will generally be outside of an acceptable deviation range from the reference breath inputted by the first user.

However, known devices provide no way of enabling updating of a reference value in the breath measurement apparatus, as a consequence of a user' s reference or reference range deviating over time due to improvement in, for example, physical condition, or worsening of a physical condition.

Thus, with known devices, there is no way of preventing the device from recording a deviation from the reference if a user's breath is outside the original reference parameters. Furthermore, in known devices, there is no way of updating the reference to correspond to a user's improving or decreasing physical condition, without a user re-setting the reference each time the reference is desired to be updated.

It is therefore an aim of preferred embodiments of the present invention to overcome or mitigate at least one problem in the prior art, whether expressly disclosed herein or not . Summary of the Invention

According to a first aspect of the invention, there is provided a calorimeter comprising a means to determine the energy of the metabolism of a user from one or more breaths of the user, a means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, a means to detect a deviation from said reference breath in subsequent breaths of a user, and a means to adjust the recorded reference breath upon detection of a trend in deviation from the recorded reference breath in said subsequent breaths .

Preferably the device comprises a housing in which each of the components is located.

Preferably the means to determine the energy of metabolism of a user comprises any suitable means, such as an oxygen meter, capable of determining oxygen content of an inhaled and/or exhaled breath, and the oxygen meter may operably co-operate with a flow meter.

Preferred breath parameters which may be recorded by the means to record at least one parameter per breath include at least one parameter selected from inhalation speed, exhalation speed, inhalation volume, exhalation volume, oxygen content of exhaled breath, carbon dioxide content of exhaled breath, time intervals between breaths, number of breaths in a pre-determined time period, duration of an exhalation, duration of an inhalation, force of an exhaled breath, force of an inhaled breath, calories expended, and the rate of change of any one of the aforesaid parameters .

The means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath preferably comprises at least two of the parameters listed herein above, and for example, may- comprise means to detect duration of exhalation, exhalation volume and force of exhalation, for example.

Thus, depending on the parameter or parameters to be recorded in a reference breath of a user, the means to record the or each parameter may be one or more means selected from an inhalation speed sensor, an exhalation speed sensor, an inhalation volume sensor, an exhalation volume sensor, an inhalation duration sensor, an exhalation duration sensor, an inhalation pressure sensor, an exhalation pressure sensor, an oxygen meter, a carbon dioxide meter, a flow meter or any combination thereof.

In addition to any of the above breath parameters, as the device is a calorimeter, it will of course include means to calculate metabolic rate of the user, which may comprise means to determine one or more of the aforesaid parameters, especially flow rate and oxygen consumption or carbon dioxide content of an exhaled or inhaled breath, most preferably means to determine breath flow rate and a means to determine oxygen consumption, such as a flow meter and oxygen meter for example. Therefore the means to determine the energy of metabolism of a user and the means to record one or more parameters of a breath and record said parameter or parameters as a reference breath may comprise the same means in some preferred embodiments.

Suitably the means to record at least one parameter of a breath of a user and record said parameters of said breath as a reference breath comprise means to record the parameter or parameters from an unforced breathing state.

By "unforced" we mean that the user breaths naturally without unduly blowing, sucking, exhaling the lungs' void space volume, or otherwise actively altering the speed and/or volume of an inhaled and/or exhaled breath whether consciously or subconsciously. Thus an "unforced" breathing state may be a resting breathing state or the breathing state of a user after physical activity or exertion.

Preferably the means to detect a deviation from the reference breath in subsequent breaths of a user comprises means to record the at least one parameter of the subsequent breaths of a user. Suitably the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, and the means to detect a deviation from said reference breath in subsequent breaths of a user are one and the same. Suitably the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, and the means to record the parameter in subsequent breaths comprises a data storage means. Suitably the data storage means comprises a machine-readable medium, on which data may be stored by any suitable means, such as optically, magnetically, chemically, electrically, or any combination thereof, for example. Preferably the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, and the means to record the or each parameter of subsequent breaths comprises an electronic calculation means in conjunction with a data storage means. The electronic calculation means may comprise an electronic computer, for example . Suitably the data storage means comprises a computer hard disc, chip-based memory (such as RAM or EPROM for example) , floppy disc, compact disc, DVD (digital versatile disc), mini-disc, or the like. While the above mentioned data storage means are all digital, the data storage means may comprise analogue data storage means .

The means to detect a deviation from said reference breath in subsequent breaths of a user may comprise an electronic calculation means, capable of determining a difference in the recorded parameter of the reference breath, and parameters recorded of subsequent breaths. The electronic calculation means may comprise an electronic computer, or any other suitably electronic calculation means.

The means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath and the means to record the parameter from said subsequent breaths may comprise a means to record a defined range of the or each parameter. For example, the parameter range may comprise a range of acceptable values of inhalation speed, exhalation speed, inhalation volume, exhalation volume or the like, for example. In this way, the means to detect a deviation from said reference breath in said subsequent breaths of a user may determine whether the parameter from a subsequent breath falls within the acceptable range recorded for the reference breath or not .

The means to adjust the recorded reference breath on detection of a trend in deviation from the recorded reference breath in said subsequent breaths may comprise a means to adjust the recorded reference breath on detection of a defined deviation value or range from the or each parameter recorded for the reference breath. Thus, the means to adjust the recorded reference breath may adjust the recorded reference breath upon a signal from the means to detect deviation from said reference breath in a plurality of subsequent breaths of a user, when said deviation means detects a deviation within a defined range from the parameter recorded in the reference breath. For example, the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath may comprise means to record inhalation speed, and the means to adjust the recorded reference breath may activate only when the inhalation speed of subsequent breaths deviates within a user- or machine-defined range from the recorded reference breath. The means to adjust the recorded reference breath on detection of a trend in deviation from the recorded reference breath in subsequent breaths may activate only upon detection of a deviation within a defined range of a machine or user defined minimum number of subsequent breaths.

The means to adjust the recorded reference breath on detection of a trend in deviation from the recorded reference breath in subsequent breaths may comprise a means to adjust the parameter range of the reference breath, the acceptable deviation range from the parameter or parameter range, or both. This enables the acceptable deviation value or range to be updated as the parameter or parameters of the reference breath is or are updated over time .

The calorimeter may further comprise a means to determine when a deviation from the recorded reference breath surpasses a defined value or range, and may further comprise a means to indicate when the deviation which surpasses the defined amount from the recorded reference breath occurs. The indicator means may be a visual indicator means, an audio indicator means, or both visual and audio indicator means.

Suitable visual indicator means include light emitting diodes, liquid crystal display panels, warning lights or lamps, visual text displays and the like, for example. Suitable audio indicator means include warning buzzers, bells, sirens and the like, and vocal warnings, for example. Suitably the indicator means is capable of displaying the extent of the deviation from the acceptable value or range of the recorded reference breath. Suitably the indicator means is capable of displaying which parameter recorded in the reference breath has deviated past the acceptable value, in one or more subsequent breaths .

The calorimeter may comprise means to temporarily prevent operation of the calorimeter by a user, when a deviation outside an acceptable value or range from the reference breath is detected in one or more subsequent breaths. The device operation prevention means may prevent operation for a defined time period, which may be set by a user, or may prevent operation until a user manually overrides the operation prevention means, such as by way of a manual switch, or other actuator, for example. The device operation prevention means may comprise a switch or trigger, for example, which is activated when the deviation detection means detects a deviation in one or more subsequent breaths which surpasses a user defined acceptable value or range from the reference breath. The device operation prevention means may prevent subsequent breaths from a user from entering the calorimeter, or may prevent recordal of subsequent breaths, for example. The calorimeter may further comprise means for a user to accept or decline a breath recordal, whether the breath is within the acceptable deviation value or range of the reference breath or not . The breath recordal acceptance means may comprise a switch, or similar actuator which in use must be activated to accept a breath reading in order for the reading to be recorded by the means to record subsequent breaths of a user.

Preferably the device comprises a fluid inlet, which in use is arranged to allow passage of a user's breath into and out of the calorimeter.

Preferably the fluid inlet comprises a mouthpiece, integral with or connected to the fluid inlet. Suitably the mouthpiece is detachably connected to the fluid inlet, which enables the mouthpiece to be cleaned between uses.

The mouthpiece may comprise a mask arranged in use to be placed over at least the mouth of a user, and more preferably the mouth and nose of a user. Suitably the mask has securing means, arranged to secure the mask to a user's face. A mask is preferable as a mouthpiece as it encourages normal, unforced breathing from a user. Other mouthpieces, such as tubes which are arranged to partly enter a user's mouth, may tend to encourage a user to force breaths into and/or out of a fluid inlet.

According to a second aspect of the invention there is provided a method of monitoring breaths comprising the steps of: (a) providing a calorimeter comprising a means to determine the energy of metabolism of a user, and a means to record at least one parameter of breath of a user and record said parameter of said breath as a reference breath;

(b) recording at least one parameter of the breath of a user and recording said parameter of said breath as a reference breath;

(c) recording subsequent breaths of a user;

(d) detecting a trend in deviation from the recorded reference breath in said subsequent breaths;

(e) adjusting the recorded reference breath upon detection of the trend in deviation from the recorded reference breath in said subsequent breaths .

Preferably, the number of subsequent breaths recorded in step (c) is at least 2, more preferably at least 3, still more preferably at least 5, yet more preferably at least 10 and most preferably at least 50.

Preferably the method comprises a step of detecting whether a deviation occurs outside of a defined deviation range, and subsequently preventing adjustment of the reference breath using a result obtained from a subsequent breath outside of the deviation range.

Preferably the calorimeter is as described in the first aspect of the invention. Preferably the means to determine the energy of metabolism of a user from one or more breaths of a user, and means to record at least one parameter of a breath of a user and record said parameter are as described in the first aspect of the invention. Brief Description of the Drawings

For better understanding of the invention and to show how embodiments of the same may be put into effect, the various aspects of the invention will now be described with reference to the accompanying drawings in which:

Figure IA is a schematic side view of a first embodiment of a calorimeter of the invention;

Figures IB and 1C illustrate schematic side views of a second embodiment of the calorimeter of the invention;

Figure 2 illustrates a flow diagram of the essential components of the calorimeter of Figures IA to 1C; and

Figure 3 is a graph of recordal of five breaths of a user of the calorimeter of Figures IA or IB .

Description of the Preferred Embodiments

We refer firstly to Figure IA which illustrates a first embodiment of a calorimeter 2 of the invention. The calorimeter 2 comprises a housing 4, fluid inlet 6 connected to and in fluid communication with the housing 4, a display screen 8 on the housing 4, and a mouthpiece 10 comprising a one-way valve 12 and a mask 14, the mouthpiece 10 being connected to the distal end of the fluid inlet 6.

We refer now to Figure 2 which illustrates a flow diagram of the essential electronic components of the calorimeter 2. Within the housing 4 are located a means to determine the energy of metabolism of a user from one or more breaths of the user, which comprises an oxygen sensor in the form of an MOx sensor 20 supplied by City Technology Ltd, UK, and an AWM5000 flow sensor 22 supplied by- Honeywell Inc, USA, a means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath 24, 26 in the form of an NEC PD78FO148M6 MCU supplied by NEC₇ a means to detect a deviation from said reference breath in subsequent breaths of a user, and a means to adjust the recorded reference breath upon detection of the trend in deviation from the recorded reference breath in said subsequent breaths 24, 26 also in the form of the NEC PD78FO148M6 MCU, supplied by NEC, and a display 28 to display the calculations made.

Referring now to Figures IB and 1C, in a second embodiment of a calorimeter 2, like numerals represent like components. In the second embodiment shown in Figures IB and 1C, the fluid inlet 6 does not include a separate mouthpiece 10, and therefore the fluid inlet 6 comprises the mouthpiece itself. Other than this change, this embodiment is identical to that described in Figure IA.

In use, the calorimeter 2 of any of Figures IA, IB and 1C is described as follows.

A user firstly breathes into the mask 14 of the mouthpiece 10 on the calorimeter 2 of Figure IA, or breathes directly into the fluid inlet 6 of the calorimeter 2 of Figures IB and 1C. The means to record the reference breath 24, 26 then records at least one parameter of a breath of the user, and records the parameter as the reference breath.

In the embodiment shown in Figures IB and 1C, after recordal of the reference breath, the display screen 8 may indicate that the reference breath has been recorded, for example by displaying the word "OK" as shown in Figure IB.

A user may then continue to breathe into the calorimeter 2. As the user exhales subsequent breaths into the calorimeter 2, the means to record subsequent breaths 24, 26, and a means to detect a deviation from the reference breath 24, 26 in said subsequent breaths monitors whether a deviation has occurred in subsequent breaths. The means to detect a deviation from said reference breath 24, 26 in subsequent breaths then compares the deviation against a pre-defined deviation value or range limit. If deviation is detected in a plurality of subsequent breaths, the means to detect deviation from said reference breath 24, 26 in the subsequent breaths of a user calculates whether the trend in deviation in a plurality of subsequent breaths is within a pre-defined acceptable value or range. If the trend in deviation in subsequent breaths is within a pre-defined range of acceptable deviation, the means to adjust the recorded reference breath upon detection of a trend in deviation from the recorded reference breath in the subsequent breaths updates the reference breath in consequence of the new trend in the parameter or parameters recorded for the reference breaths in the subsequent breaths .

Figure 3 illustrates a graph of the recordal of five example breaths utilising the calorimeter 2 of Figures IA, IB and 1C. The X axis shows length of breath in milliseconds, whilst the Y axis shows the maximum peak of each breath in the form of electronic counts corresponding to flow. A calculation of the area underneath the curve defined by the two breaths give breath volume in each breath. The first breath is recorded as a reference breath, and any one of a range of suitable parameters such as length of time of the breath, maximum peak, area, ratio of area to length, or the like can be recorded, or any combination thereof.

As seen in Figure 3, in the example breaths shown, the second breath is approximately the same as the first reference breath and the means to detect a deviation from the reference breath 24, 26 does not detect a deviation and hence does not update the reference breath.

On recording the parameters of the third breath, the means to detect a deviation from the reference breath 24, 26 in subsequent breaths detects that the parameters (such as volume of the breath) recorded for the reference breath have deviated from the reference breath, in the third breath. The means to detect a deviation from said reference breath 24, 26 in subsequent breaths then determines whether the deviation in the parameters is within an acceptable deviation range pre-defined in the calorimeter 2. The pre-defined acceptable deviation range may be defined by a user inputting a preferred acceptable deviation range, or maybe factory set. If the deviation of the third breath is not within an acceptable deviation range, then the display 8 may indicate an error, as shown in Figure 1C, and the calorimeter 2 may actuate a calorimeter operation prevention means (not shown) , to prevent subsequent breaths being accepted into the calorimeter, or recorded by the calorimeter 2, until a user has taken action on the error reading. The user may override the device operation prevention means or may reset the device, as appropriate. If the means to detect a deviation from said reference breath 24, 26 in subsequent breaths determines that breath 3 of Figure 3 is within an acceptable deviation range, then the means to record the deviation may record the or each parameter of breath 3. If the user then breathes into the calorimeter 2 , to produce breath 4 of Figure 3 , which has substantially the same parameters as Figure 3, the means to detect a deviation from the reference breath in subsequent breaths 24, 26, will detect that the parameters of breath 4 are substantially identical to the parameters of breath 3, and also within the acceptable deviation range.

As at least two breaths have been determined to have an acceptable deviation range from the reference breath, the means to adjust the recorded reference breath 24, 26 upon detection of a trend in deviation from the recorded reference breath in subsequent breaths then calculates a new reference breath (such as an average volume of breaths 1-4 of Figure 3, for example) by comparing the trend from breaths 3 and 4, with the parameter or parameters recorded in the initial reference breath, breath 1. In this way, the reference breath is updated as a trend in deviation occurs .

As can be seen in Figure 3, the fifth breath then has a lower volume than breaths 3 and 4, and the means to detect a deviation in the reference breath 24, 26 detects the deviation in breath 5 compared to the updated reference, and determines whether the deviation in breath 5 falls within an acceptable deviation range from the updated reference. In this way, the reference breath is updated as a trend in deviation occurs. This is particularly useful for users of the calorimeter who, for example, are undergoing weight loss, and for whom physical condition is improving over time. With such users, parameters such as peak flow rate, maximum volume, etc, will increase over a period of time as the user's physical condition improves, and the initial reference breath may therefore be erroneous after a certain period of time. Therefore, updating and adjusting of the reference breath in response to a trend in deviation of the parameters recorded as a reference breath, in subsequent breaths, enables a user to continue to use the calorimeter 2 without recourse to resetting or restarting any calculations.

Another advantage in the calorimeter 2 having a means to detect a deviation from said reference breath in subsequent breaths of a user, and a means to adjust the recorded reference breath upon detection of a trend in deviation from the recorded reference breath in said subsequent breaths, is the ability for the calorimeter 2 to determine when a subsequent breath is outside of the acceptable deviation range, and therefore prevent use of the calorimeter 2 by a person other than the original user, if desired. For example, if a first user inputs a reference breath, and a second user attempts to use the calorimeter 2, the means to detect deviation from said reference breath in subsequent breaths of a user may detect that the deviation is outside of the acceptable range, and initiate actuation of a calorimeter operation prevention means (not shown) , and indicate an error in the display screen 8 of the calorimeter 2.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A calorimeter comprising a means to determine the energy of the metabolism of a user from one or more breaths of the user, a means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, a means to detect a deviation from said reference breath in subsequent breaths of a user, and a means to adjust the recorded reference breath upon detection of a trend in deviation from the recorded reference breath in said subsequent breaths.

2. The calorimeter according to claim 1, wherein the calorimeter comprises a housing in which each of the components is located.

3. The calorimeter according to claim 1 or claim 2, wherein the means to determine the energy of metabolism of a user comprises any suitable means, such as an oxygen meter, capable of determining oxygen content of an inhaled and/or exhaled breath, and the oxygen meter operably cooperates with a flow meter.

4. The calorimeter according to any one of claims 1 to 3 , wherein the breath parameters which are recorded by the means to record at least one parameter per breath include at least one parameter selected from inhalation speed, exhalation speed, inhalation volume, exhalation volume, oxygen content of exhaled breath, carbon dioxide content of exhaled breath, time intervals between breaths, number of breaths in a pre-determined time period, duration of an exhalation, duration of an inhalation, force of an exhaled breath, force of an inhaled breath, calories expended, and the rate of change of any one of the aforesaid parameters.

5. The calorimeter according to claim 4, wherein the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath comprises means to detect at least two of the breath parameters .

6. The calorimeter according to any one of claims 1 to 5 , wherein depending on the breath parameter or parameters to be recorded in a reference breath of a user, the means to record the or each parameter is one or more means selected from an inhalation speed sensor, an exhalation speed sensor, an inhalation volume sensor, an exhalation volume sensor, an inhalation duration sensor, an exhalation duration sensor, an inhalation pressure sensor, an exhalation pressure sensor, an oxygen meter, a carbon dioxide meter, a flow meter or any combination thereof.

7. The calorimeter according to any preceding claim, further comprising means to calculate metabolic rate of the user.

8. The calorimeter according to claim 7, wherein the means to calculate metabolic rate of the user comprises means to determine one or more of the breath parameters .

9. The calorimeter according to claim 7 or claim 8, wherein the means to calculate metabolic rate of the user comprises means to determine one or more of flow rate and oxygen consumption or carbon dioxide content of an exhaled or inhaled breath.

10. The calorimeter according to claim 9, wherein the means to determine breath flow rate is a flow meter and the means to determine oxygen consumption is an oxygen meter.

11. The calorimeter according to any one of claims 7 to 10, wherein the means to determine the energy of metabolism of a user and the means to record one or more parameters of a breath and record said parameter or parameters as a reference breath comprises the same means .

12. The calorimeter according to any preceding claim, wherein the means to record at least one parameter of a breath of a user and record said parameters of said breath as a reference breath comprise means to record the parameter or parameters from an unforced breathing state.

13. The calorimeter according to any preceding claim, wherein the means to detect a deviation from the reference breath in subsequent breaths of a user comprises means to record the at least one parameter of the subsequent breaths of a user.

14. The calorimeter according to any preceding claim, wherein the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, and the means to detect a deviation from said reference breath in subsequent breaths of a user are the same .

15. The calorimeter according to any preceding claim, wherein the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, and the means to record the parameter in subsequent breaths comprises a data storage means .

16. The calorimeter according to claim 15, wherein the data storage means comprises a machine-readable medium, on which data can be stored by any suitable means, such as optically, magnetically, chemically, electrically, or any combination thereof.

17. The calorimeter according to any preceding claim, wherein the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath, and the means to record the or each parameter of subsequent breaths comprises an electronic calculation means in conjunction with a data storage means .

18. The calorimeter according to claim 16 wherein the electronic calculation means comprises an electronic computer.

19. The calorimeter according to any one of claims 14 - 17, wherein the data storage means comprises a computer hard disc, chip-based memory (such as RAM or EPROM) , floppy disc, compact disc, DVD (digital versatile disc) , mini-disc, or the like.

20. The calorimeter according to any one of claims 14 - 17, wherein the data storage means is an analogue data storage means.

21. The calorimeter according to any preceding claim, wherein the means to detect a deviation from said reference breath in subsequent breaths of a user comprises an electronic calculation means, capable of determining a difference in the recorded parameter of the reference breath, and parameters recorded of subsequent breaths.

22. The calorimeter according to claim 21, wherein the electronic calculation means comprises an electronic computer, or any other suitably electronic calculation means .

23. The calorimeter according to any preceding claim, wherein the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath and the means to record the parameter from said subsequent breaths comprises a means to record a defined range of the or each parameter.

24. The calorimeter according to claim 23, wherein the parameter range comprises a range of acceptable values.

25. The calorimeter according to claim 23 or claim 24, wherein the parameter range is one of the parameters of inhalation speed, exhalation speed, inhalation volume, exhalation volume or the like.

26. The calorimeter according to claim 24 or claim 25, wherein the means to detect a deviation from said reference breath in said subsequent breaths of a user determines whether the parameter from a subsequent breath falls within the acceptable range recorded for the reference breath or not .

27. The calorimeter according to any preceding claim, wherein the means to adjust the recorded reference breath on detection of a trend in deviation from the recorded reference breath in said subsequent breaths comprises a means to adjust the recorded reference breath on detection of a defined deviation value or range from the or each parameter recorded for the reference breath.

28. The calorimeter according to claim 27, wherein the means to adjust the recorded reference breath adjusts the recorded reference breath upon a signal from the means to detect deviation from said reference breath in a plurality of subsequent breaths of a user, when said deviation means detects a deviation within a defined range from the parameter recorded in the reference breath.

29. The calorimeter according to claim 27 or claim 28, wherein the means to record at least one parameter of a breath of a user and record said parameter of said breath as a reference breath comprises means to record inhalation speed, and the means to adjust the recorded reference breath activates only when the inhalation speed of subsequent breaths deviates within a user- or machine- defined range from the recorded reference breath.

30. The calorimeter according to any one of claims 27 -

29, wherein the means to adjust the recorded reference breath on detection of a trend in deviation from the recorded reference breath in subsequent breaths activates only upon detection of a deviation within a defined range of a machine or user defined minimum number of subsequent breaths .

31. The calorimeter according to any one of claims 27 -

30, wherein the means to adjust the recorded reference breath on detection of a trend in deviation from the recorded reference breath in subsequent breaths comprises a means to adjust the parameter range of the reference breath, the acceptable deviation range from the parameter or parameter range, or both.

32. The calorimeter according to any one of claims 27 -

31, wherein the acceptable deviation value or range are updated as the parameter or parameters of the reference breath is or are updated over time.

33. The calorimeter according to any preceding claim, further comprising a means to determine when a deviation from the recorded reference breath surpasses a defined value or range .

34. The calorimeter according to any preceding claim, further comprising a means to indicate when the deviation which surpasses the defined amount from the recorded reference breath occurs .

35. The calorimeter according to claim 34, wherein the indicator means is a visual indicator means, an audio indicator means, or both visual and audio indicator means.

36. The calorimeter according to claim 35, wherein the visual indicator means includes light emitting diodes, liquid crystal display panels, warning lights or lamps, visual text displays and the like.

37. The calorimeter according to claim 35, wherein the audio indicator means includes warning buzzers, bells, sirens and the like, and vocal warnings.

38. The calorimeter according to any one of claims 34 -

37, wherein the indicator means is capable of displaying the extent of the deviation from the acceptable value or range of the recorded reference breath.

39. The calorimeter according to any one of claims 34 -

38, wherein the indicator means is capable of displaying which parameter recorded in the reference breath has deviated past the acceptable value, in one or more subsequent breaths.

40. The calorimeter according to any preceding claim, further comprising means to temporarily prevent operation of the calorimeter by a user, when a deviation outside an acceptable value or range from the reference breath is detected in one or more subsequent breaths .

41. The calorimeter according to claim 40, wherein the device operation prevention means prevents operation for a defined time period, which is set by a user, or prevents operation until a user manually overrides the operation prevention means, such as by way of a manual switch, or other actuator.

42. The calorimeter according to claim 40 or claim 41, wherein the device operation prevention means comprises a switch or trigger which is activated when the deviation detection means detects a deviation in one or more subsequent breaths which surpasses a user defined acceptable value or range from the reference breath.

43. The calorimeter according to any one of claims 40 - 42, wherein the device operation prevention means prevents subsequent breaths from a user from entering the calorimeter, or prevents recordal of subsequent breaths.

44. The calorimeter according to any preceding claim, further comprising means for a user to accept or decline a breath recordal, whether the breath is within the acceptable deviation value or range of the reference breath or not .

45. The calorimeter according to claim 44, wherein the breath recordal acceptance means comprises a switch, or similar actuator which in use must be activated to accept a breath reading in order for the reading to be recorded by the means to record subsequent breaths of a user.

46. The calorimeter according to any preceding claim, further comprising a fluid inlet, which in use is arranged to allow passage of a user's breath into and out of the calorimeter.

47. The calorimeter according to claim 46, wherein the fluid inlet comprises a mouthpiece, integral with or connected to the fluid inlet .

48. The calorimeter according to claim 47, wherein the mouthpiece is detachably connected to the fluid inlet, which enables the mouthpiece to be cleaned between uses.

49. The calorimeter according to claim 46 or claim 47, wherein the mouthpiece comprises a mask arranged in use to be placed over at least the mouth of a user the mouth and nose of a user.

50. The calorimeter according to claim 49, wherein the mask has securing means, arranged to secure the mask to a user's face.

51. The calorimeter according to any one of claims 46 - 49, wherein the mouthpiece is a tube arranged to partly enter a user's mouth.

52. A method of monitoring breaths comprising the steps of:

(a) providing a calorimeter comprising a means to determine the energy of metabolism of a user, and a means to record at least one parameter of breath of a user and record said parameter of said breath as a reference breath;

(b) recording at least one parameter of the breath of a user and recording said parameter of said breath as a reference breath; (c) recording subsequent breaths of a user;

53. The method according to claim 52, wherein the number of subsequent breaths recorded in step (c) is at least 2.

54. The method according to claim 52 or claim 53, wherein the number of subsequent breaths recorded in step (c) is at least 3.

55. The method according to any one claims 52 - 54, wherein the number of subsequent breaths recorded in step

(c) is at least 5.

56. The method according to any one of claim 52 - 55, wherein the number of subsequent breaths recorded in step (c) is at least 10.

57. The method according to any one of claims 52 - 56, wherein the number of subsequent breaths recorded is at least 50.

58. The method according to any one of claims 52 - 57, wherein the method comprises a step of detecting whether a deviation occurs outside of a defined deviation range, and subsequently preventing adjustment of the reference breath using a result obtained from a subsequent breath outside of the deviation range.

59. The method according to any one of claims 52 - 58 wherein the calorimeter is as described in the any of claims 1 - 51.

60. The method according to any one of claims 52 - 59, wherein the means to determine the energy of metabolism of a user from one or more breaths of a user, and means to record at least one parameter of a breath of a user and record said parameter are as described in any of claims 1

51.