NOTE: THESE SUMMARIES ARE OF HISTORICAL INTEREST ONLY AS THE REFERENCED COCHRANE REVIEWS ARE NOW OUTDATED
STUDIES
Inhaled Air
- House dust mite control: Forty-nine trials
- Pet allergen control: Two trials
- Feather versus non-feather bedding : No trials
- Humidity control : One trial
- Ionisers : Six trials
- Speleotherapy (staying in a cave) : Three trials
Dietary Changes
- Dietary salt reduction or exclusion for allergic asthma : Six trials
- Calorie reduction : One trial
- Tartrazine exclusion for allergic asthma : Six trials
- Dietary fish oil for asthma in adults and children: Nine trials
- Vitamin C supplementation : Eight trials
- Selenium supplementation: One trial
Complementary therapy
- Acupuncture : Eleven trials
- Homeopathy: Six trials
Physical therapies
- Alexander technique : One trial
- Breathing exercises: Seven trials
- Inspiratory muscle training: Five trials
- Physical training : Thirteen trials
- Manual therapies: Three trials
Asthma causes difficulties in breathing that are usually occasional (intermittent) but which can cause a great deal of distress, interfering with normal activities and with sleep. Rarely, they can even result in death. Asthma is a frequently-occurring condition in both children and adults. Acute asthma is a common medical emergency. For uncertain reasons, asthma has markedly increased in prevalance in many parts of the world in recent decades. Asthma is often related to allergies, which are also on the rise. Difficult breathing can be triggered by allergens, breathing cold air, exercise, and other circumstances.
People with asthma are frequently treated with pharmaceutical drugs. Until the 1980s, drugs were mainly used to treat breathing symptoms, but since that time asthma has come to be regarded as a chronic inflammatory disease that may benefit from ongoing pharmaceutical prevention measures even when symptoms are not present. Inhaled steroid and beta-agonist drugs currently provide the backbone of approaches of conventional medicine to asthma but do have side effects and are financially costly.
Because asthma is so common, a wide variety of non-medicinal approaches have been tried to prevent or better asthma. Most of the alternative or complementary approaches considered in these web pages aim more at preventing asthma episodes than at treating them when they occur.
Changing the Environment
One approach is to change the environment in such as way that inhaled air is different. This may involve conditioning the air in some way – elimination of allergens, humidification -- or going to a different environment (underground air). Available evidence about some of these environmental manipulations has been carefully studied. Another approach to preventing asthma is to change or supplement the diet in some way. Sometimes this is motivated by a belief that modern changes in diet may contribute to asthma. Complementary therapies and various breathing exercises have been used to try to improve chronic asthma.
In summary
Nineteen reviews looked at a number of interventions to improve asthma. Some studies located involved children, some adults. Some used the intervention in addition to pharmaceutical drugs (as an “adjunct”). The better studies used objective measurements of breathing capacity such as forced vital capacity (FVC) – the amount of air one can breathe out in a breath – or FEV1 – the amount of air one can breathe out in one second - as well as people’s reports about their own breathing. Unfortunately, in some cases no studies could be located, and in many cases the studies involved only a few people (which increases the risk of bias or of good results just because of chance) or were done poorly.
It is disappointing to note that evidence to date provides no strongly successful non-medical strategy for dealing with asthma.
One measure that was definitely not helpful was house dust mite control measures for asthma. Trying to rid a house of dust mites is generally a great deal of work, but has been found in a number of reasonably large trials not to improve breathing meaningfully nor to reduce medication usage.
Another generally useless method is excluding tartrazine (a dye often used as a food colorant) from the diet for asthma. It has been tested in six small studies of good design. All the studies indicate that normally tartrazine exclusion is not beneficial to asthmatics. It is still possible that a few rare individuals might be sensitive to tartrazine, but this would be very uncommon.
Measures that were not helpful to improve asthma in trials but the trials were few, poor, small, or even non-existent so do not really settle the question: pet allergen control reduction measures (air filtration units, washing, dander sprays – no trials done of the latter two methods), use of feather or non-feather bedding (no trials), dehumidifiers in the home, ion generators in the home, acupuncture, chiropractic, homeopathic treatment, Alexander technique (no trials), physical training (did not improve asthma but improved cardiopulmonary function).
Measures that were possibly somewhat helpful to improve asthma in trials but the trials were few and/or poor and/or small and do not provide good evidence for a conclusion: breathing exercises, massage therapy, going underground into a cave or mine for asthma, dietary salt reduction, dietary calorie reduction, fish oil supplementation of the diet (no consistent beneficial effect), selenium supplementation.
Vitamin C supplementation: Research shows that there is not an additional benefit to adding Vitamin C for adults with asthma already taking inhaled steroids. For others, evidence does not show a significant effect thus far but further research is warranted.
Inspiratory muscle training: This increased maximum inspiratory pressure but the evidence doesn’t show whether this helps the asthma.
HOUSE DUST MITE CONTROL MEASURES FOR ASTHMA
Debris from mites is a major allergen present in house dust. Carpets, upholstered furniture, and bedding often harbour this allergen. It seems logical that reducing dust mite allergen levels would likely reduce asthma symptoms for those who are sensitive to house dust mites.
Both chemical and physical methods are used with the objective of reducing dust mite allergen levels. Chemical methods include use of acaricides (various pesticides that kill mites). Physical methods include washing, heating, vacuum-cleaning, ventilation, freezing, barrier methods, air filtration and ionisers.
What the synthesised research says
Chemical and physical methods aimed at reducing exposure to house dust mite allergens do not have the evidence supporting their recommended use for reducing asthma. A number of trials have failed to find a benefit for asthma of house dust mite control measures.
How it was tested
A thorough search of the medical literature found 49 trials involving 2733 patients that met pre-set criteria. Thirty-one trials evaluated physical methods, 10 chemical methods, and 8 a combination of physical and chemical methods. Dust mite control measures were compared with placebo or no treatment.
The most frequently reported outcome, peak flow in the morning, showed a standardised mean difference of –0.02 (range -0.13 to 0.08). There were no statistically significant differences in number of patients improved, asthma symptom scores, or medication usage.
Side effects and general cautions
House dust mite control methods can be labor-intensive and time-consuming, constituting a severe burden if there is not associated benefit. The reviewers comment that total removal of an agent patients are proved to be sensitive to would likely be effective – and removal of the patient from the home to a high altitude or a hospital has helped in some observational studies. The probable explanation for lack of effectiveness of dust mite reduction measures is that even stringently-applied physical and chemical efforts cannot reduce mite allergens to a low enough level to help asthma clinically. However, it is also a possibility that removing only one allergen when a patient has a number of allergies might have limited benefit.
Source
Gøtzsche PC, Johansen HK, Schmidt LM, Burr ML. House dust mite control measures for asthma. Cochrane Database of Systematic Reviews 2004, Issue 4. Art. No.: CD001187. DOI: 10.1002/14651858.CD001187.pub2.
PET ALLERGEN CONTROL MEASURES FOR ALLERGIC ASTHMA
Some people with asthma are allergic to pet dander and reducing exposure to pet dander could in theory improve asthma symptoms. Guidelines on management of allergic asthma have recommended pet removal from the home. When the pets are not removed, measures such as air filtration units to reduce pet dander, washing of pets, and anti-dander sprays are sometimes used with the intent of reducing exposure to allergens emanating from pet hair and skin.
What the synthesised research says
There was a lack of evidence about pet allergen control measures, which means that no firm conclusions can be reached about methods to reduce pet allergens for asthma.
How it was tested
The researchers made a thorough search of the medical literature to identify randomised controlled trials that compared an active pet allergen reduction measure with a control in pet-allergic patients with stable asthma. Two studies that were small but of good quality, involving 57 people, were located and analysed. Both involved use of air filtration units. One used a Honeywell Envirocare HEPA filter, and one used a Phillips air cleaner. No significant differences between intervention and control groups were found in either study.
Source
Kilburn S, Lasserson TJ, McKean M. Pet allergen control measures for allergic asthma in children and adults. Cochrane Database of Systematic Reviews 2001, Issue 1. Art. No.: CD002989. DOI: 10.1002/14651858.CD002989.
FEATHER VERSUS NON-FEATHER BEDDING FOR ASTHMA
In the past, asthmatics were often advised by allergists to use synthetic bedding rather than feather bedding, with the idea that feather bedding might contain substances provoking asthma in those allergic to them. Another reason for discouraging feather bedding was the idea that this type of bedding ,may harbour more dust mite matter, to which many asthmatics are sensitive. Recently, however, two epidemiological studies have indicated that those using feather pillows may actually have a lower rate of asthma than those who use synthetic fibres. Little to nothing is known about what type of bedding is healthier for asthmatics. It would be highly desirable to ascertain which kind of bedding is preferable.
What the synthesised research says
No evidence was available from trials with a control group, which means there is no strong evidence basis for conclusions about feather versus non-feather bedding for asthmatics.
How it was tested
The researchers searched the medical literature for randomised controlled trials, but could not locate any that met pre-set criteria. One trial was excluded because it combined feather bedding with another intervention.
Side effects and general cautions
With no trials available to study, information about adverse effects of feather or non-feather bedding is unavailable.
Source
Campbell F, Jones K, Gibson P. Feather versus non-feather bedding for asthma. Cochrane Database of Systematic Reviews 2000, Issue 4. Art. No.: CD002154. DOI: 10.1002/14651858.CD002154.
HUMIDITY CONTROL FOR CHRONIC ASTHMA
Dust mites, which many asthmatics have a sensitivity to, thrive at certain humidity levels. Using dehumidifiers to reduce home humidity to a level inhospitable to dust mites could in theory reduce dust mite levels and improve asthma symptoms, but it is not known if this works in practice. Humidity control is sometimes recommended in asthmatic patients’ homes but there is no consensus about its usefulness.
What the synthesised research says
There is not enough evidence to reach a conclusion about the value of dehumidifiers in the homes of asthmatics.
How it was tested
The researchers searched clinical trial registries to identify controlled trials that investigated the effects of dehumidification on asthma symptoms. One low-quality study with 40 participants did not find a decrease in asthma symptoms, although it did find a decrease in dust mite levels and in antigen levels.
Side effects and general cautions
No evidence about adverse effects is available.
Source
Singh M, Bara A, Gibson P. Humidity control for chronic asthma. Cochrane Database of Systematic Reviews 2002, Issue 1. Art. No.: CD003563. DOI: 10.1002/14651858.CD003563.NOTE: The one trial included in this review was also included in the review, House dust mite control measures for asthma, which discusses dehumidifiers and other measures for dust mite allergen control.
IONISERS FOR CHRONIC ASTHMA
Laboratory studies show some changes in breathing with ion generators. Ion generators have been marketed to people for use in their homes as a treatment for asthma. Not much is known about their efficacy for this purpose.
What the synthesised research says
Few controlled studies have been conducted on the use on ion generators in the home for reducing asthma. The studies that have been conducted demonstrate no clear benefit for ionisers in improving asthma symptoms or lung function.
How it was tested
The researchers made a search of various trial registries and an alternative medicine database to identify randomised controlled trials of ion generators for asthma.
Six small studies involving 106 people met inclusion criteria and were analysed. Five studies involved use of negative ion generators. Three studies did not find a significant difference in asthma symptoms or rescue medication usage in treatment and control groups. No study found a significant differences in measures of lung function.
One study involved a positive ion generator in the laboratory, and suggested that positively ionised air might worsen exercise-induced asthma, but this was not a clear effect.
Side effects and general cautions
The studies were so small they might have failed to detect a beneficial effect.
One study reported an increase in night-time cough with use of a negative ion generator, but results were not statistically significant. The small trial sizes limit the ability to detect adverse effects.
Source
Blackhall K, Appleton S, Cates CJ. Ionisers for chronic asthma. Cochrane Database of Systematic Reviews 2003, Issue 2. Art. No.: CD002986. DOI: 10.1002/14651858.CD002986. NOTE: Also see the review House dust mite control measures for asthma.
SPELEOTHERAPY FOR ASTHMA
Speleotherapy involves the use of caves or other underground environments (such as salt or potash mines), and has been used extensively for asthmatics in some Central and Eastern European countries. Benefits are variously attributed to special air quality, underground climate, air pressure, or radiation (present in certain kinds of mines).
People with asthma go to special health resorts offering access to these caves or mines. They spend short periods underground with the intent of improving their asthma. At times they do special physical or breathing exercises in these environments. Sometimes, there are wards built to permit longer periods underground. Since the underground environments differ in their characteristics, various sorts of speleotherapy should be considered as a group of treatments rather than a single intervention.
What the synthesised research says
Two of three small controlled trials reported a beneficial short-term effect on asthma, which was considered as insufficient evidence to support staying in caves to reduce asthma.
How it was tested
The medical literature and trial registries were searched and experts were consulted to locate controlled clinical trials comparing speleotherapy for asthma against no treatment or another asthma treatment.
Three small trials were located involving 124 asthmatic children, but two were of very poor quality. On balance there is insufficient evidence to reach any conclusions at all about effectiveness of speleotherapy for asthma.
Side effects and general cautions
If more research is done, it is important to know whether any beneficial effect is purely short-term or whether there is any longer-lasting benefit.
The presence of high levels of radon in some of the caves (thought to be therapeutic) is a possible but not proven cause for concern.
Source
Beamon S, Falkenbach A, Fainburg G, Linde K. Speleotherapy for asthma. Cochrane Database of Systematic Reviews 2001, Issue 2. Art. No.: CD001741. DOI: 10.1002/14651858.CD001741.
DIETARY SALT REDUCTION OR EXCLUSION FOR ALLERGIC ASTHMA
Rates of asthma vary widely among geographic regions, and it has been suggested that one factor might be differing rates of salt consumption.
What the synthesised research says
There is limited evidence available about the effect of reducing dietary salt on asthma and firm conclusions cannot be reached. Only some of the studies carried out showed a small improvement of lung function or rescue inhaler use with low-salt diets. Overall, any benefits were not clear.
How it was tested
The researchers searched the medical literature to identify controlled trials that investigated the effects of salt consumption on asthma symptoms. Six randomised controlled trials of small size and short duration were found.
Side effects and general cautions
Reducing salt intake tends to reduce blood pressure a bit, which is in general beneficial.
Source
Ram FSF, Ardern KD. Dietary salt reduction or exclusion for allergic asthma. Cochrane Database of Systematic Reviews 2004, Issue 2. Art. No.: CD000436. DOI: 10.1002/14651858.CD000436.pub2.
CALORIE REDUCTION FOR ASTHMA
Rates of asthma vary widely among geographic regions, and asthma is increasing in recent years. It has been suggested that one factor might be an increase in consumption of high-calorie diets. There is some association between obesity and asthma, though their causal relation is not known.
What the synthesised research says
Very limited evidence suggests a possible benefit of lowered calorie consumption on asthma. More studies are needed, as a firm conclusion cannot be reached at this time.
How it was tested
The researchers searched the medical literature to identify controlled trials that investigated the effects of lowered caloric consumption on asthma symptoms.
One controlled trial involving 38 patients with chronic asthma was found. it was of only fair methodological quality. The study showed significantly higher FEV1 and FVC in the group on a restricted diet.
Side effects and general cautions
No data about serious adverse effects was reported in the included trial.
Source
Cheng J, Tao Pan, GH Ye, Q Liu. Calorie controlled diet for chronic asthma. The Cochrane Database of Systematic Reviews 2003, Issue 2. Art. No.: CD004674.pub2. DOI: 10.1002/14651858.CD004674.pub2.
TARTRAZINE EXCLUSION FOR ALLERGIC ASTHMA
Tartrazine is a yellow dye derived from coal tar. It is used very commonly as a food colorant and is also used to color medications. There is conflicting evidence about whether it is likely to cause exacerbations of asthma. Some studies have found a positive association, especially in asthmatics who are sensitive to aspirin. Use of tartrazine is banned in Norway and has at times been banned in Austria and Germany. It would be valuable to understand whether there is a role for tartrazine exclusion in asthma management.
What the synthesised research says
There is no evidence that tartrazine makes asthma worse and no evidence that avoiding it makes people with asthma any better. It is still possible that a very few individuals with proven tartrazine sensitivity might benefit from excluding tartrazine.
How it was tested
The researchers made a search for randomised controlled trials relating to tartrazine and asthma, including allergic asthma. These could involve exclusion of tartrazine from the diet, but could also involve ascertaining the results of oral administration of tartrazine on asthmatics (tartrazine challenge). They found six small randomised controlled trials that were consistent in their findings.
Side effects and general cautions
There is no dietary need for tartrazine, but avoiding the many products that contain it could be limiting and burdensome.
Source
Ram FS, Ardern KD. Tartrazine exclusion for allergic asthma. Cochrane Database of Systematic Reviews 2001, Issue 4. Art. No.: CD000460. DOI: 10.1002/14651858.CD000460.
DIETARY FISH OIL FOR ASTHMA IN ADULTS AND CHILDREN
Eskimos eat a lot of fish, and have little asthma. There is a theory that an ingredient in fish oil may reduce inflammation, including lung inflammation believed to lead to asthma attacks. It would be valuable to know whether a diet naturally high in fish oil can aid asthma, or whether fish oil supplements are of benefit.
What the synthesised research says
On the whole, adding marine fatty acids to the diet does not appear to improve asthma. Studies so far mostly do not show any consistent beneficial effect on asthma of fish oil supplementation. One study in children that combined dietary prescriptions with fish oil supplementation showed improved peak flow and reduced asthma medication use.
How it was tested
The researchers searched the Cochrane Airways Group Specialised Register through January 2004 for trials with a control group that dealt with fish oil or a fishy diet to treat asthma and lasted more than four weeks. They also consulted bibliographies of retrieved articles as well as contacting fish oil manufacturers.
Nine randomised controlled trials met inclusion criteria. Eight compared a fish oil supplement to a placebo. The ninth compared a high-dose to a low-dose fish oil supplement. There were no trials of a fishy diet except for one that combined it with a fish oil supplement. Two studies were done in children; seven in adults.
Side effects and general cautions
There is no evidence to suggest adverse effects from increasing fish oil consumption.
Source
FCK Thien, S De Luca, R Woods, MJ Abramson. Dietary marine fatty acids (fish oil) for asthma in adults and children. Cochrane Database of Systematic Reviews 2002, Issue 2. Art. No.: CD001283. DOI: 10.1002/14651858.CD001283.
VITAMIN C SUPPLEMENTATION FOR ASTHMA
Vitamin C is abundant in the extracellular fluid lining the lung. Low vitamin C intake has been associated with pulmonary dysfunction, and asthmatic people tend to have lower vitamin C levels than non-asthmatic people. Persons who have examined scientific literature recently have reached conflicting conclusions on the potential value of Vitamin C in managing asthma.
What the synthesised research says
There is not enough evidence to determine whether or not Vitamin C supplementation can benefit people with asthma. There is evidence from one controlled that the addition of Vitamin C to inhaled steroids in patients with asthma is not of benefit.
How it was tested
Researchers searched the medical literature for randomised controlled trials dealing with Vitamin C to treat asthma.
Eight trials met inclusion criteria. All compared a Vitamin C group against a placebo group. Only four presented results in a form permitting analysis, and differences in these studies meant results could not be combined in a meta-analysis. The individual studies did not show a significant effect on any asthma outcome.
One study in 201 adults also taking inhaled steroids found statistically significant evidence that there is not an important lung benefit for such patients from the addition of Vitamin C.
Source
Ram FSF, Rowe BH, Kaur B. Vitamin C supplementation for asthma. Cochrane Database of Systematic Reviews 2004, Issue 3. Art. No.: CD000993. DOI: 10.1002/14651858.CD000993.pub2.
SELENIUM SUPPLEMENTATION FOR ASTHMA
Observational studies indicate that patients with chronic asthma may have comparatively low levels of selenium, a trace mineral. This, and some theoretical reasons related to potential activity of selenium in the body, has caused some to wonder whether selenium supplementation might be useful. Selenium supplementation is not currently recommended in guidelines to supplement medication usage for asthma patients.
What the synthesised research says
One one small trial provides limited evidence that selenium supplementation might be useful to asthma patients already taking asthma medications.
How it was tested
The researchers searched for randomised controlled trials of adding selenium to asthma medication in patients receiving asthma medication. One trial with 24 patients reported clinical improvement in the selenium-supplemented group compared with the asthma-medication-alone group, but the clinical improvement was not supported by changes in objective lung function measurements.
Side effects and general cautions
No firm conclusion can be reached from this one small trial.
Source
Allam MF, Lucena RA. Selenium supplementation for asthma. Cochrane Database of Systematic Reviews 2004, Issue 2. Art. No.: CD003538. DOI: 10.1002/14651858.CD003538.pub2.
ACUPUNCTURE FOR CHRONIC ASTHMA
Acupuncture was historically used to treat asthma, and is frequently used today in many countries to treat asthma. The researchers searched the medical literature to identify trials that compared the benefit of acupuncture for asthma against some type of placebo, some other asthma treatment, or no treatment.
What the synthesised research says
Current evidence from trials has not shown a benefit of acupuncture for asthma. In general acupuncture groups did no better than control groups given sham acupuncture.
How it was tested
Eleven studies with 324 participants met inclusion criteria. Studies included children and adults; some were on medication. Laser and needle acupuncture were used and acupuncture techniques and points varied between trials. Trial quality and reporting were generally poor. There was also considerable variation in the acupuncture points used and outcomes measured.
Side effects and general cautions
No serious adverse effects were noted in the trials that reported them. The groups involved may not have been large enough for possible adverse effects to show up.
Source
McCarney RW, Brinkhaus B, Lasserson TJ, Linde K. Acupuncture for chronic asthma. Cochrane Database of Systematic Reviews 2003, Issue 3. Art. No.: CD000008. DOI: 10.1002/14651858.CD000008.pub2.
HOMEOPATHY FOR CHRONIC ASTHMA
Homeopathy is a widely-used form of complementary medicine that is used to treat asthma.
What the synthesised research says
Current evidence does not provide a basis for recommending homeopathic treatment for asthma.
How it was tested
Six trials with a total of 556 people met predetermined criteria. These trials are probably not typical of homeopathic treatment, which is normally individualised. No trial reported a significant difference in validated asthma symptom scales between treatment and control groups.
Side effects and general cautions
No adverse effects were reported in the trials included, but the small trial sizes limit the ability to detect adverse effects.
Source
McCarney RW, Linde K, Lasserson TJ. Homeopathy for chronic asthma. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD000353. DOI: 10.1002/14651858.CD000353.pub2.
ALEXANDER TECHNIQUE FOR CHRONIC ASTHMA
The Alexander technique was invented by an Australian, FM Alexander and is popular among performing artists. It is designed to be a form of education that teaches the body to move efficiently and work better. It has been used by asthmatics to try to improve breathing, and some of these believe the Alexander technique has been helpful to them.
What the synthesised research says
No evidence at all from trials with a control group is available to provide a basis for conclusions about use of the Alexander technique to improve asthma.
How it was tested
One clinical trial related to Alexander technique and breathing was located, but it did not involve people diagnosed with asthma.
Side effects and general cautions
With no trials available to study, information about adverse effects of the Alexander technique is also unavailable.
Source
Dennis J, Cates CJ. Alexander technique for chronic asthma. Cochrane Database of Systematic Reviews 2000, Issue 2. Art. No.: CD000995. DOI: 10.1002/14651858.CD000995.
BREATHING EXERCISES FOR ASTHMA
Various breathing exercises have been used at different places and times in an effort to improve asthma. Breathing exercises used for asthma vary immensely which makes comparisons difficult.
What the synthesised research says
Overall, there are few trials about effectiveness of breathing retraining for asthma. General conclusions could not be reached, as treatment interventions and outcome measurements from the seven trials varied considerably. Benefits were found in isolated outcome measures in single studies, but no firm conclusions can be drawn. Results are suggestive and more research on specific techniques is warranted, hopefully on a larger scale.
How it was tested
Seven studies involving 292 patients were located. Some of the participants were using inhaled steroids or rescue bronchodilators. The breathing methods included yoga, the Buteyko method, the Papworth method, deep diaphragmatic breathing, and others. Reduction of medication use was seen in two studies, but another study found no reduction. Varied results were found on whether lung function improved or not.
Side effects and general cautions
There is a concern that some types of breathing exercises involving exaggerated expiration may exacerbate asthmatic symptoms. Some breathing exercise systems are designed to avoid this problem. Some subjects (including those in a control group) experienced asthma exacerbations during the trials, but these were not clearly related to any intervention.
Source
Holloway E, Ram FSF. Breathing exercises for asthma. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD001277. DOI: 10.1002/14651858.CD001277.pub2.
INSPIRATORY MUSCLE TRAINING FOR ASTHMA
People with COPD lose muscle mass including in respiratory muscles. It is possible but not proven that asthma may cause similar loss of respiratory muscle mass. If this does occur, training for respiratory muscles might help with asthma. There is a device sold on the Internet that provides external resistance. Claims are made that this benefits breathing in asthmatic persons and athletes. People inhale using the device to strengthen the muscles.
What the synthesised research says
The trials did not provide enough evidence to reach a conclusion about whether training to increase maximum respiratory pressure provides any clinical benefit to asthmatics.
How it was tested
Five small trials, four done by the same group, showed that doing the training does increase maximum inspiratory pressure. Many people doing the training were taking medical drugs for asthma concurrently. Only one study measured rescue inhaler use and showed a reduction. No study reported inhaled steroid use or asthma symptoms in usable form.
Side effects and general cautions
The review does not mention whether any adverse effects were monitored in the trials.
Source
Ram FSF, Wellington SR, Barnes NC. Inspiratory muscle training for asthma. Cochrane Database of Systematic Reviews 2003, Issue 3. Art. No.: CD003792. DOI: 10.1002/14651858.CD003792.
PHYSICAL TRAINING FOR ASTHMA
People in good physical shape may have less need for ventilation during exercise, lowering risk of exercise-induced asthma. Many asthmatics report doing better with asthma when in good physical condition. Physical training programs are sometimes recommended for asthmatics.
What the synthesised research says
Regular physical activity does not worsen lung function and provides other benefits to the exercising person.
How it was tested
Based on 13 controlled studies involving 455 participants that were located, exercise improves cardiopulmonary function but has not been shown to improve asthmatic lung function.
Side effects and general cautions
People with asthma may be reluctant to exercise since sometimes exercise provokes asthma, so this is a risk of a physical training program. This problem can be managed (for instance, by pre-treatment before exercise with medication).
Source
Ram FSF, Robinson SM, Black PN, Picot J. Physical training for asthma. Cochrane Database of Systematic Reviews 2005, Issue 4. Art. No.: CD001116. DOI: 10.1002/14651858.CD001116.pub2.
MANUAL THERAPIES FOR ASTHMA
Various manual therapies such as chest tapping, vibration, postural drainage, massage, chiropractic, physiotherapy and osteopathy are sometimes used with the aim of bettering asthma. It would be important to know whether any of these actually are of benefit.
What the synthesised research says
There is little available evidence from 3 randomised controlled trials involving 156 patients, and what there is does not support recommendation of manual therapies for asthma. Two trials of chiropractic (one of good methodological quality) did not find a benefit for asthma. One trial of massage therapy did find improvements in measures of lung function, but the trial was poorly reported and the data cannot be regarded as confirmed. However, there is a need for adequately-powered research of a variety of manual therapies.
Side effects and general cautions
Only one trial reported on adverse effects and did not find any. With the wide variety of potential manual therapies, reporting on the nature of adverse effects, if any, in future trials is important.
Source
Hondras MA, Linde K, Jones AP. Manual therapy for asthma. Cochrane Database of Systematic Reviews 2005, Issue 2. Art. No.: CD001002. DOI: 10.1002/14651858.CD001002.pub2.