GB2347869A

GB2347869A - Breathing apparatus

Info

Publication number: GB2347869A
Application number: GB9917359A
Authority: GB
Inventors: Thomas Tsoi Hei Ma
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-15
Filing date: 1999-07-24
Publication date: 2000-09-20
Also published as: GB9917359D0

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 with little or no oxygen, a flow regulating and limiting 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 into the close vicinity of the athlete's nose to form a stratified region of the gas near the nose. In use, the athlete breathes in stratified streams of the gas and additional ambient air, the inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete.

Description

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, compare 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, decreasing appetite and increasing fat burning accompanied by a healthy weight loss.

Summary of the invention According to the present invention, there is provided a method of conditioning the air breathed by an athlete during training exercise, by blowing a concentrated stream of gas containing air with little or no oxygen into the close vicinity of the nose of the athlete to form a stratified region of the gas near the nose such that the athlete breathes in stratified streams of the gas and additional ambient air, the inhaled streams resulting in the lungs receiving a lower average oxygen concentration than the ambient air surrounding the athlete.

According to an alternative 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 with little or no 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 close vicinity of the nose of the athlete to form a stratified region of the gas near the nose such that the athlete breathes in stratified streams of the gas and additional ambient air, the 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.

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.

It is known to provide an enclosed chamber containing low oxygen air to simulate high altitude training in this manner, but this has important disadvantages that the invention avoids. Firstly the chamber itself is bulky and costly. Secondly the equipment sets out to surround the athlete with low oxygen air which is inefficient in view of the substantial size of the chamber. Thirdly it takes a long time for the oxygen concentration in the chamber to be lowered to the desired level for the same reason. Fourthly, 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. By contrast, 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.

It is also known 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 that the invention avoids. Firstly wearing a mask is cumbersome and uncomfortable and is disliked by most users. Secondly 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. Thirdly, 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. By contrast, 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 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 gas and ambient air while exercising freely and breathing normally. This makes the invention suitable for running, walking and cycling, as well as for a variety of indoor exercises.

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 connected to the gas supply by a flexible hose may be designed as a mobile system carried or worn by the athlete. In the latter case, the headset may be connected by a longer flexible hose to the gas supply for use within a predetermined area permitted by the length of the flexible hose. Of course, several people wearing headsets may be connected to a common pressurised 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 nitrogenrich 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 nitrogenrich air respectively.

The accuracy of metering of the flow of nitrogen or nitrogen-rich air into the close vicinity of the athlete's nose is not particularly important provided that the maximum flow is limited, for safety reasons, by a flow limiter so that the athlete, breathing in the stratified streams of the gas and ambient air together, will always receive at least 10% by volume of oxygen. In the case of a gas separation system supplying the gas to a single athlete, the rated capacity of the air compressor may be selected to automatically limit the maximum flow of nitrogen or nitrogen-rich air delivered to the athlete.

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 stratified gas stream with the additional air inhaled by the athlete. Preferably, the athlete's inhalation rate may be measured with a suitable sensor and the stratified 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 stratified gas stream metered accordingly.

In practice, during training exercise for an athlete breathing at a brisk inhalation rate of 120 litres/min, a concentrated stream of nitrogen blown into the close vicinity of his or her nose at a flow rate of 34 litres/min would result in the average oxygen concentration of the stratified streams inhaled into the lungs being 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 65 litres/min would also result in the average oxygen concentration of the stratified streams inhaled into the lungs being reduced to 15%.

It will be clear from the above examples that the pressurised gas supply only needs to provide a fraction of the total air breathed by the athlete. The selection of the nitrogen concentration and the flow rate of the pressurised gas is quite flexible depending on considerations of the cost and the compactness of the system. In the case of the pressurised gas supply being a gas storage cylinder, pure nitrogen at the minimum flow rate will be desirable. In the case of the pressurised gas supply being a gas separation system, the selection of the nitrogen concentration and the flow rate would depend on the relative size and cost of the membrane or sieve unit and those of the air compressor. As the size and cost of the membrane or sieve unit is typically higher than those of the air compressor, it will be more economic to use a smaller membrane or sieve unit to produce nitrogen-rich air instead of pure nitrogen.

It is recommended that the breathing apparatus should be used following a strict program designed for the individual need of the athlete. To make it easy to maintain a well managed low oxygen training program, the pressurised gas supply may be designed as a disposable gas cartridge having a small capacity just sufficient for only one training session so that a new cartridge will be used at the start of each session. Alternatively, a timer may be provided which automatically switches off the gas supply after a predetermined training period. In the latter case, the timer may additionally be programmed to deliver the gas at predetermined intervals to provide the athlete with low oxygen air in alternate periods with normal air.

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.

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 holes 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 gas and ambient air while exercising freely and breathing normally. This makes the invention suitable for running, walking and cycling, as well as for a variety of indoor exercises.

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 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 nitrogenrich air is always available from the pressurised gas supply 10 as long as the compressor 32 is running.

Instead of a selectively permeable membrane unit, a molecular sieve unit may be used in another gas separation system (not shown) performing a similar function of separating the air into two streams containing oxygen-rich air and nitrogen-rich air respectively.

Claims

1. A method of conditioning the air breathed by an athlete during training exercise, by blowing a concentrated stream of gas containing air with little or no oxygen into the close vicinity of the nose of the athlete to form a stratified region of the gas near the nose such that the athlete breathes in stratified streams of the gas and additional ambient air, the 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 of pressurised gas that consists of air with little or no 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 close vicinity of the nose of the athlete to form a stratified region of the gas near the nose such that the athlete breathes in stratified streams of the gas and additional ambient air, the 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 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 gas and ambient air while exercising freely and breathing normally.

4. A method or an apparatus as claimed in claim 1 or in claim 2 or 3 respectively, wherein the stream of gas is nitrogen-rich air containing at least 90% by volume of nitrogen.

5. A method or an apparatus as claimed in claim 1 or in claim 2 or 3 respectively, wherein the stream of gas is pure nitrogen.

6. An apparatus as claimed in claim 2 or 3, wherein the pressurised gas supply is a gas storage cylinder containing nitrogen-rich air or pure nitrogen.

7. An apparatus as claimed in claim 2 or 3, wherein the pressurised gas supply is a gas separation system comprising a selectively permeable membrane unit or a molecular sieve unit through which ambient air is forced under pressure by means of an air compressor or blower, the membrane or sieve unit 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 nose and the nitrogen-rich stream being connected to the gas discharge pipe and blown into the close vicinity of the athlete's nose.

8. An apparatus as claimed in claim 2 or 3, wherein the flow regulating means include a flow limiter for limiting the maximum flow from the pressurised gas supply, so that the athlete breathing the gas and ambient air together will always receive at least 10% by volume of oxygen.

9. An apparatus as claimed in claim 2 or 3, wherein the flow rate of the gas is varied by the flow regulating means to maintain a steady proportion of the gas blown into the close vicinity of the athlete's 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.

10. An apparatus as claimed in claim 2 or 3, wherein a timer is provided to automatically switch off the gas supply after a predetermined training period.

11. An apparatus as claimed in claim 10, wherein the timer is programmed to switch on and off the gas supply at periodic intervals.

12. An apparatus as claimed in any one of claims 2 to 11, wherein the headset and the gas supply is designed as a mobile system carried or worn by the athlete.

13. An apparatus as claimed in any one of claims 2 to 11, wherein the headset is connected by a long flexible hose to a stationary gas supply for use within a predetermined area permitted by the length of the flexible hose.