WO2000054854A2

WO2000054854A2 - Personal breathing apparatus for training athletes

Info

Publication number: WO2000054854A2
Application number: PCT/GB2000/000918
Authority: WO
Inventors: Thomas Tsoi-Hei Ma
Original assignee: Welcome To Mars Limited
Priority date: 1999-03-15
Filing date: 2000-03-13
Publication date: 2000-09-21
Also published as: GB2362831A; AU3178400A; GB0122340D0; WO2000054854A3

Abstract

An apparatus is described for use by an athlete during training exercise. The apparatus comprises a supply (10) of pressurised gas that consists of air depleted in oxygen, a flow regulating and limited valve (12) for setting the rate of discharge of the gas from the supply, and a discharge pipe (14, 15, 16) for delivering a concentrated stream of the gas towards the vicinity of the athlete's face to form a localised oxygen depleted region near the mouth and nose. In use, the athlete breathes in parallel stratified streams from the oxygen depleted region and from the ambient air, the separate inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete.

Description

PERSONAL BREATHING APPARATUS

Field of the invention

The present invention relates to a method and an apparatus for conditioning the air breathed by an athlete during training exercise.

Background of the invention

It is known that the cardiopulmonary system works at a greater intensity in low levels of oxygen found at high altitudes. This is why athletes have traditionally trained for important competitions in mountainous regions at a height where the oxygen level is as low as 10% equivalent at sea-level, compared with 21% at sea level.

It has been claimed that a well managed low oxygen training program will encourage the production of blood red cells, and is effective in increasing oxygen uptake, decreasing blood pressure, improving fitness, regulating appetite, and inducing fat burning accompanied by a healthy weight loss .

It has been proposed to provide an enclosed chamber containing low oxygen air to simulate high altitude training in this manner, but this has important disadvantages. First, the chamber itself is bulky and costly. Second, the equipment sets out to surround the athlete with low oxygen air which is inefficient in view of the substantial size of the chamber. Third, it takes a long time for the oxygen concentration in the chamber to be lowered to the desired level for the same reason. Fourth, in order to provide comfort and safety, it is necessary to control the total environment within the chamber including in addition to oxygen, other parameters such as humidity, temperature, carbon dioxide, odour, bacteria etc which could otherwise build up in the enclosed atmosphere when occupied for intensive exercise.

It is also been proposed to provide a breathing apparatus delivering through a face mask or nose mask a confined stream of conditioned air to the athlete. The conditioned air may be re-breathed air scrubbed of carbon dioxide to simulate low oxygen air. This also has important disadvantages. First, wearing a mask is cumbersome and uncomfortable and is disliked by most users. Second, the fact that the air is confined by the mask makes it necessary to deliver all the air breathed by the athlete through the mask which is inefficient and requires more breathing effort by the athlete. Third, if the conditioned air is re- breathed air, it will require even more breathing effort recycling the air and, unless further purifying steps are taken to remove odour, moisture and heat, the air will feel stale and unhygienic.

Summary of the invention

With a view of mitigating at least some of the foregoing disadvantages, there is provided in accordance with a first aspect of the present invention a method of conditioning the air breathed by an athlete during training exercise, which comprises blowing a concentrated stream of gas containing air depleted in oxygen towards the vicinity of the face of the athlete to form a localised oxygen depleted region in the vicinity of the mouth and nose, whereby the athlete breathes in parallel stratified streams from the oxygen depleted region and from the ambient air, the separate inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete .

According to a second aspect of the invention, there is provided an apparatus for conditioning the air breathed by an athlete during training exercise, comprising a supply of pressurised gas that consists of air depleted in oxygen, a flow regulating means for setting the rate of discharge of the gas from the supply, and a discharge pipe for delivering a concentrated stream of the gas into the vicinity of the face of the athlete to form a localised oxygen depleted region in the vicinity of the mouth and nose, whereby in use of the apparatus the athlete breathes in parallel stratified streams from the oxygen depleted region and from the ambient air, the separate inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete.

To achieve a stratified region of the gas near the nose, the gas must be discharged from a short distance relative to the athlete's nose so that it has little chance to mix with ambient air. Inhalation by the athlete would automatically draw the concentrated gas and additional ambient air in parallel streams into the lungs resulting in the lungs receiving the correct proportions of the gas and ambient air similar to that of low oxygen air. This eliminates the need to deliver the full flow of pre-mixed low oxygen air to the athlete and significantly reduces the complexity, size and flow capacity of the breathing apparatus. Instead, the breathing apparatus only needs to supply a fraction of the inhaled air volume and therefore can be made into a simple, compact and light-weight unit. Furthermore, by concentrating the gas near the nose, utilisation of the gas is conserved and wastage is reduced.

By contrast with the known low oxygen chambers, the present invention recognises that if air with a nitrogen to oxygen ratio of 6:1 is required instead of 4:1, it is only necessary to supply the missing two parts of nitrogen in each seven parts of air inhaled by the athlete. By blowing a concentrated stream of nitrogen or nitrogen-rich air into the close vicinity of the face of the athlete to form a stratified region near the nose, the athlete would automatically breathe in stratified streams of the gas and ambient air, the inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete. Thus there is no need for expensive and cumbersome apparatus which totally engulfs the athlete in a controlled atmosphere. Furthermore, by contrast with the prior proposed use of a face mask, the present invention delivers a concentrated stream of the gas to the athlete unobtrusively, the concentrated stream constituting only the dilution gas which is a small fraction of the total air breathed by the athlete and is inhaled effortlessly by the athlete together with more ambient air in parallel streams while breathing normally unhampered by any enclosure or mask that would have contacted his or her face and caused discomfort.

Preferably, the gas is nitrogen-rich air containing at least 90% by volume of nitrogen. Alternatively, the gas may be pure nitrogen.

Air typically comprises four parts of nitrogen to one part of oxygen (disregarding smaller quantities of other gases such as carbon dioxide etc) . When breathed in at normal atmospheric pressure at sea level, the lungs will receive a certain mass of oxygen during each inhalation. When training at higher altitudes, the reduced air pressure means that less oxygen is received in the lungs with each inhalation and the aim of the invention is to achieve a similar effect, not by reducing the air pressure but by reducing the oxygen concentration alone.

Preferably, the nitrogen or nitrogen-rich air may be delivered from a pressurised gas supply to a pipe mounted on a headset worn by the athlete and positioned to discharge the gas from a short distance relative to the athlete's nose, the pipe moving with the athlete's head so that the athlete inhales substantially constant proportions of the concentrated gas and ambient air while exercising freely and breathing normally. This makes a mobile personal breathing apparatus suitable for running, walking and cycling, as well as for a variety of indoor and outdoor exercises.

The personal breathing apparatus of the present invention can also be used for passive training during resting, reading or sleeping while breathing low oxygen air which would continue to stimulate the cardiopulmonary system.

Conveniently, the pressurised gas supply is a gas storage cylinder containing pure nitrogen. The gas cylinder is designed to be easily replaced when empty and is small enough to fit into a mobile pack or a stationary pack. In the former case, the headset may be connected to a portable gas supply by a flexible hose in a compact system which is easily carried or worn by the athlete. In the latter case, the headset may be connected by a longer flexible hose to a fixed gas supply for use within a predetermined area permitted by the length of the flexible hose. Of course, several people wearing headsets may share a common gas supply such as in a large gymnasium.

Instead of supplying nitrogen from a nitrogen gas cylinder which has to be replaced when empty and refilled in a factory, a continuous supply of nitrogen or nitrogen-rich air may be provided by a gas separation system comprising a selectively permeable membrane unit through which ambient air is forced under pressure by means of an air compressor or blower. Such a gas separation system is well known in industry and can be adapted to a smaller scale to meet either the mobile or the stationary specifications of the apparatus of the invention. The membrane is designed such that the more mobile oxygen and water molecules permeate through the membrane while the less mobile nitrogen molecules are left behind, thus separating the air into two streams containing moist oxygen-rich air and nitrogen-rich air respectively. Depending on the effective area of the membrane, a purity of greater than 99% nitrogen in the nitrogen-rich stream may be achieved if desired though unnecessary for the purpose of the present invention. The oxygen-rich stream will be discharged into the ambient atmosphere away from the athlete's nose while the nitrogen- rich stream will be connected to the gas discharge pipe and blown into the close vicinity of the athlete's nose.

Instead of a selectively permeable membrane unit, a molecular sieve unit may be used in another gas separation system performing a similar function of separating the air into two streams containing oxygen-rich air and nitrogen- rich air respectively.

As a further alternative, a batch of material for reversibly chemically binding with oxygen may be used to absorb oxygen from pressurised air thereby producing a batch of nitrogen gas for the breathing apparatus. For example, cyanocobaltate described in US Patent No. 5,294,418 can absorb as much as 2.3 mmol of oxygen per gram of the material . Thus 1 kg of the material can absorb enough oxygen from 250 litres of air to produce nearly 200 litres of nitrogen gas. In this case, a portable unit comprising an air compressor forcing air through a 1 kg bed of the material may be used to supply a 200 litres batch of nitrogen gas before the bed becomes saturated and needs to be regenerated. To perform the regeneration, the bed is subjected to a vacuum pressure which unbinds the oxygen. Such vacuum pressure may be provided by connecting the portable unit to an external vacuum source such as a domestic vacuum cleaner, or by reversing the air flow path of the compressor in the portable unit so that, instead of compressing air through the bed to produce nitrogen gas, the compressor sucks air from the bed to desorb and discharge the oxygen. In either case, the portable batch unit is self-regenerating and may be used in batches again and again without need of replacement canisters.

The flow rate of the nitrogen or nitrogen-rich air may be varied by a flow regulating valve to maintain a steady proportion of the concentrated gas stream with the additional ambient air inhaled by the athlete. Preferably, the athlete's inhalation rate may be measured with a suitable sensor and the concentrated gas stream metered according to the measured inhalation rate indicated by the sensor. Alternatively, the athlete's inhalation rate may be inferred by other monitoring means, such as measuring the athlete's heart rate or exhalation rate, and the concentrated gas stream metered accordingly.

In practice, during training exercise for an athlete breathing at a brisk inhalation rate of 2.0 litres/sec, a concentrated stream of pure nitrogen gas blown into the close vicinity of the nose at a flow rate of 0.5 litres/sec would result in the average oxygen concentration of the total inhaled streams of gas and air to be reduced to approximately 15%. Alternatively, a concentrated stream of nitrogen-rich air containing 90% nitrogen blown into the close vicinity of the nose at a flow rate of 1.0 litres/sec would also result in the average oxygen concentration of the total inhaled streams to be reduced to 15%.

The accuracy of metering of the concentrated gas stream is not particularly important provided that the maximum flow is limited, for safety reasons, by a flow limiter so that the athlete inhaling the concentrated gas stream and additional ambient air together will always receive at least 10% by volume of oxygen.

To conserve the gas supply, an on/off valve may be provided for switching on the flow when the athlete is inhaling and switching off the flow when the athlete is exhaling. To achieve synchronisation without relying on detecting the breathing rhythm of the athlete, a pacing system may be provided for pre-setting the rhythm of switching on and off consecutively of the gas flow by the on/off valve and for generating a series of audible signals synchronised with the switching rhythm for prompting the athlete to inhale and exhale correspondingly in response.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of an apparatus of a preferred embodiment of the invention,

Figure 2 is a schematic view of a pressurised gas supply incorporating a gas separation system,

Figure 3 and 4 are schematic views similar to that of Figure 2, showing alternative embodiments of a gas separation system, and

Figure 5 is a schematic diagram of a pacing system for prompting the athlete to inhale and exhale according to a gas conservation program.

Detailed description of the preferred embodiments

In Figure 1, an athlete's head is shown wearing a headset 20 carrying a gas discharge pipe 15 which is bent and positioned at a short distance relative to the athlete's nose to direct a metered concentrated stream of nitrogen or nitrogen-rich air through hole 16 into the close vicinity of the nose while the athlete also breathes in additional ambient air represented by the long arrows. The nitrogen or nitrogen-rich air is supplied from a pressurised gas supply 10 with a flow regulating and limiting valve 12 along a flexible hose 14 to the gas discharge pipe 15. The discharge pipe 15 moves with the athlete's head so that the athlete inhales substantially constant proportions of the concentrated gas and ambient air while moving freely and breathing normally.

The gas supply 10 may be small enough to be designed as a mobile unit carried or worn by the athlete to be used anywhere. Alternately the gas supply 10 may be a stationary unit supplying the headset via a longer flexible hose 14. In the latter case, the athlete can still move freely within a predetermined area limited by the length of the hose 14.

The pressurised gas supply 10 shown in Figure 1 may be a gas storage cylinder containing nitrogen at high pressure, the cylinder being easily replaced when empty and refilled.

Alternatively, the pressurised gas supply 10 in Figure 1 may be a module containing a continuous gas separation system as shown in Figure 2. The gas separation system comprises a housing 10 containing an air compressor 32 driven by a motor 30. Ambient air is drawn into the compressor 32 via an inlet pipe 34 (annotated as stream A) and the compressed air is delivered from the compressor 32 into a plenum chamber 42 from which it is forced through a selectively permeable membrane unit 44 constructed as a bunch of hollow fibres. Oxygen and water molecules permeate through the walls of the hollow fibres of the membrane unit 44 and are collected into a first accumulation chamber 48 from which they are released into the ambient atmosphere away from the athlete's nose via a first outlet pipe 38

(annotated as stream C) . The nitrogen-rich air passes along the hollow fibres of the membrane unit 44 and is collected into a second accumulation chamber 46 from which it is delivered via a second outlet pipe 36 (annotated as stream B) to the flexible hose 14 to be blown into the close vicinity of the athlete's nose as shown in Figures 1. Thus a concentrated stream of nitrogen-rich air is always available from the pressurised gas supply 10 as long as the compressor 32 is running.

As a further alternative, a batch of solid state material such as cyanocobaltate may be used for reversibly chemically binding with oxygen, absorbing oxygen from pressurised air and producing a batch of nitrogen gas for the breathing apparatus. In Figure 3, a portable unit 10 comprising an air compressor 32 forcing air through a bed of the material 43 is used to produce a batch of nitrogen gas until the bed 43 becomes saturated with oxygen and needs to be regenerated. The size of the bed is selected to be large enough to provide an optimum usage period between regenerations and small enough to be conveniently portable. To perform the regeneration, the bed 43 is subjected to a vacuum pressure which unbinds the oxygen. Such vacuum pressure is provided in Figure 3 by connecting the outlet pipe 35 of portable unit 10 to an external vacuum source such as a domestic vacuum cleaner, and blocking the inlet pipe 34 with a plug 37.

In Figure 4, which shows a similar batch air separation system as that in Figure 3, the inlet and outlet of the compressor 32 are provided with respective two-way valves 31, 33 for selecting the air flow path through the compressor 32 according to one of two modes. In the first mode, as illustrated in Figure 4, the compressor 32 draws ambient air from outside the portable unit 10 and forces it through the bed 43 where oxygen is absorbed leaving the nitrogen gas to be discharged through the outlet pipe 35. When the bed 43 becomes saturated with oxygen and needs to be regenerated, the air flow path through the compressor 32 is switched to the second mode by rotating the two-way valves 31, 33 clockwise by 90° so that the compressor 32 draws air from inside the portable unit 10 and discharges it outside, creating a vacuum over the bed 43 and desorbing the oxygen in the bed 43. A plug 37 is also provided for blocking the outlet pipe 35 if necessary.

In Figure 5, the lower half of the diagram is similar to that of Figure 1 with the addition of an on/off valve (22) in the flexible pipe (14) for switching on and off consecutively the gas flow delivered to the athlete. In the upper half of the diagram, a pace-setting unit 30 generates a series of pairs of pace-setting signals at regular time intervals which is preset by the athlete according to the pace of his training program. Each pair of pace-setting signals is sent to a flow switching unit 32 which switches the valve 22 on and off consecutively. At the same time a flow regulating unit 34 adjusts the flow regulating valve 12 to set the appropriate flow rate of the gas when the valve 22 is open. The series of pace-setting signals are also sent to a time delay unit 36 which introduces an adjustable time delay after the pace-setting signals before triggering a series of audio signals in a prompting unit 38. By varying the time delay, any mismatch in the response times of the switching of the flow and the sending of the audio signals may be eliminated so that the flow will arrive at the nose of the athlete at the same time as the audio signal is received by the athlete.

In the Figure, a series of pairs of beeping tones is transmitted by the prompting unit 38 to an earphone 24 in the headset 20. The athlete responds to the beeping tones and inhales and exhales correspondingly, thus synchronising his breathing rhythm with the arrival and interruption of the gas flow respectively.

Claims

1. A method of conditioning the air breathed by an athlete during training exercise, which comprises blowing a concentrated stream of gas containing air depleted in oxygen towards the vicinity of the face of the athlete to form a localised oxygen depleted region in the vicinity of the mouth and nose, whereby the athlete breathes in parallel stratified streams from the oxygen depleted region and from the ambient air, the separate inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete.

2. An apparatus for conditioning the air breathed by an athlete during training exercise, comprising a supply

(10) of pressurised gas that consists of air depleted in oxygen, a flow regulating means (12) for setting the rate of discharge of the gas from the supply (10), and a discharge pipe (14) for delivering a concentrated stream of the gas into the vicinity of the face of the athlete to form a localised oxygen depleted region in the vicinity of the mouth and nose, whereby in use of the apparatus the athlete breathes in parallel stratified streams from the oxygen depleted region and from the ambient air, the separate inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete.

3. An apparatus as claimed in claims 2, wherein the gas is delivered from a pressurised gas supply (10) to a pipe (15, 16) mounted on a headset (20) to be worn by the athlete and to be positioned to discharge the gas from a short distance relative to the athlete's face, whereby as the pipe moves with the athlete's head the athlete in use of the apparatus inhales in parallel substantially constant proportions of the concentrated gas and ambient air.

4. An apparatus as claimed in claim 2 or 3 , wherein the stream of gas comprises at least 90% by volume of nitrogen, the remainder comprising oxygen and other trace gases .

5. An apparatus as claimed in claim 2 or 3 , wherein the stream of gas comprises substantially pure nitrogen.

6. An apparatus as claimed in any of claims 2 to 5 , wherein the pressurised gas supply is a gas storage cylinder (10) .

7. An apparatus as claimed in any of claims 2 to 5 , wherein the pressurised gas supply is a continuous gas separation system (10) comprising a selectively permeable membrane unit or a molecular sieve unit (44) through which ambient air is forced under pressure by means of a pump (32), the membrane or sieve unit (44) separating the air into two streams containing oxygen-rich air and nitrogen- rich air respectively, the oxygen-rich stream being discharged into the ambient atmosphere away from the athlete's face and the nitrogen-rich stream being connected to the gas discharge pipe (15, 16) and blown towards the vicinity of the athlete's face.

8. An apparatus as claimed in claim 2 to 5 , wherein the pressurised gas supply is a batch gas separation system (10) comprising a bed of solid state material (43) for reversibly chemically binding with oxygen, the material absorbing oxygen from pressurised air and producing a batch of nitrogen gas for the breathing apparatus .

9. An apparatus as claimed in claim 8, wherein the solid state material includes cyanocobaltate.

10. An apparatus as claimed in claim 8 or 9 , comprising means for regenerating the bed of solid state material by exposing the material to a vacuum source in order to desorb the absorbed oxygen.

11. An apparatus as claimed in claim 2 or 3 , wherein in use the flow rate of the gas is varied by the flow regulating means (12) to maintain a steady proportion of the gas blown towards the vicinity of the athlete's mouth and nose with the total air volume inhaled by the athlete, the gas being metered according to a measured or an inferred inhalation rate of the athlete.

12. An apparatus as claimed in claim 2 or 3 , wherein the flow regulating means (12) additionally includes a flow limiter for limiting the maximum flow from the pressurised gas supply.

13. An apparatus as claimed in claim 2 or 3 , wherein an on/off valve (22) is provided for switching on the gas flow when the athlete is inhaling and switching off the gas flow when the athlete is exhaling.

14. An apparatus as claimed in claim 13 , wherein a pacing system (30, 32, 36, 38) is provided for pre-setting the rhythm of switching on and off consecutively of the gas flow by the on/off valve (22) and for generating a series of audible signals synchronised with the switching rhythm for prompting the athlete to inhale and exhale correspondingly in response.

15. An apparatus as claimed in any of claims 2 to 14, in which the gas supply is portable by the athlete during training .