The Breathing/Oxygen series on Health Rising continues with a rare clinical trial in chronic fatigue syndrome (ME/CFS) that’s designed to improve breathing, increase blood CO2 levels, and hopefully improve a wide number of symptoms.

The Breathing/Oxygen Series on Health Rising

Heather Edgell will use her Solve M.E. Ramsay Award to improve breathing in ME/CFS and long COVID, and hopefully increase CO2 levels and improve some symptoms.

Dr. Heather Edgell seems to be in a kind of sweet spot. Interested in fainting disorders – her Ph.D. focused on the cardiovascular and autonomic aspects of fainting – she founded an autonomic and cardiorespiratory testing lab called the Women’s Cardiovascular Health Lab at York University in Toronto.

That led her to postural orthostatic tachycardia syndrome (POTS) and chronic fatigue syndrome (ME/CFS) – two diseases with a predominance in women – both of which feature orthostatic intolerance (problems standing and/or sitting upright). Now we have long COVID – another female-dominated disorder that produces similar effects.


Given the gender imbalance found in these diseases, I asked about the role female hormones might play. Dr. Edgell stated that much more work on this needs to be done and noted that estrogen is a potent vasodilator and progesterone is a respiratory stimulant. High levels of both can increase the fight/flight response.

Ramsay Award ME/CFS and Long-COVID Clinical Trial

Last year, Dr. Edgell won one of the most interesting Solve M.. Ramsay Awards in memory. Edgell’s clinical trial to assess the ability of inspiratory muscle training to improve breathing – and more importantly, increase CO2 levels, is exciting, not just because potentially provides affordable help now, but because of how much physiological research is embedded in it.

Inspiratory Muscle Training (IMT)

Inspiratory muscle trainer

One of many inspiratory muscle trainers on the market. Inspiratory muscle training can instill a new, healthier breathing pattern that been shown to breathlessness and improve a host of factors.

“Inspiratory muscle training”, or IMT, is a respiratory exercise program that’s used to help people with asthma, bronchitis, emphysema, stroke, etc. breathe better. One study of people with heart failure using a cardiopulmonary exercise test (CPET) found that a home-based program improved their aerobic capacity (peak VO2) (!).

Even people in great shape can benefit from these exercises. The Training4Endurance website, for instance, has a page that demonstrates how athletes can use it to race faster and longer.

Studies have found that inspiratory muscle training can improve sleep and balance, reduce blood pressure and breathlessness, and improve functioning. The balance issue demonstrates how far the impact of weakened respiratory muscles can go. Apparently, when we encounter a soft or uneven surface, our back muscles kick in to keep us stable. Because the diaphragm supports the back muscles, a weak diaphragm keeps the back muscles from doing their job. When that happens, we turn to our ankle muscles – which results in more swaying. That’s why one inspiratory muscle study, which used the POWERbreathe® Medic Plus device, found that breathing retraining improved the participants’ balance.

Training the Respiratory Muscles

Inspiratory muscle training uses a small device that restricts the airflow in order to increase respiratory muscle strength. Edgell determines your maximum inhalation and then sets the pressure of the device at 80% of that. You then breathe through the device a certain number of times a day. She said it feels as if you were breathing through a straw.

Three times a week, the participants will do 6 sets of 6 repetitions. Each set will be separated by decreasing lengths of time over the 8 weeks, starting at a 30-second interim. All told 36 inhalations will be done 3 times a week.

It’s not called “inspiratory muscle training” for nothing. The program can actually retrain how you breathe and inculcate a new breathing pattern that sticks.

I asked if the increased amount of time many people with ME/CFS have to spend in bed could affect the muscles we use to breathe with. The answer was yes. Because we breathe more shallowly when we’re in bed, the muscles we ordinarily use when we are up and walking around can be detrained.

I asked if breathing retraining could help with the problems getting oxygen to diffuse into the small blood vessels of the lungs that two recent long-COVID studies found. She didn’t know but thought it might be able to.

Increasing CO2 Levels in ME/CFS and Long COVID


The breathing patterns in people with ME/CFS, fibromyalgia, POTS, and long COVID appear to be causing them to remove too much CO2, which may impede blood flows to the brain.

The primary goal of the retraining program is to increase the CO2 levels in ME/CFS and long-COVID patients’ blood. CO2 is a critical factor in the body that is produced during both anaerobic and aerobic energy production. Interestingly, our brainstem regulates our breathing based on our CO2 levels, not our oxygen levels.

We remove excessive CO2 in our blood by breathing. Breathing too much, though, by breathing too deeply, or too rapidly, or both, can remove too much CO2 – leading to hypocapnia, or low blood CO2 levels.

Hypocapnia can produce many symptoms including dizziness or lightheadedness, shortness of breath, bloating and belching, fatigue, feeling weak, cognitive and sleep problems, numbness and tingling sensations, muscle spasms, chest pain, and palpitations. Because low CO2 levels cause the blood vessels in the brain (as well as the lungs) to constrict, they could be impacting brain blood flows – a critical concern in ME/CFS and long COVID.

Hypocapnia Common

Hypocapnia, or low blood CO2 levels, have not been found in everyone with ME/CFS/FM, but appears to be present in a very substantial subset. Eighty percent of people with ME/CFS had POSH (postural orthostatic syndrome of hypocapnia) in a recent CDC orthostatic intolerance study. Some of them even exhibited low CO2 levels while lying down. Interestingly, a sudden onset of the illness, probably an infectious event, was significantly more common among the patients who demonstrated some abnormality.

Systrom found low CO2 levels in his invasive exercise studies, the Visser team found them during tilt table testing, and Naschitz found it in his ME/CFS/FM Israeli studies fifteen years ago. (He said it was “common” in fibromyalgia.). Natelson and Mancini also found it during exercise testing, and Novak found it during tilt-table testing in people with long COVID.

Move Over POTS – Hypocapnia May be a Bigger Deal in ME/CFS

Digging Deeper

Nobody has done as thorough testing as Edgell is going to do, though. She’s going to give ME/CFS and long-COVID patients 4 tests and see what happens to their brain blood flows. They include:

  1. Breathing a low oxygen content (10% O2) gas or high CO2 gas (5% CO2) for 5 minutes will test the ability of “chemoreflex” to respond. The chemoreflex alters the breathing pattern in response to changes in CO2 and oxygen. It relies on chemoreceptors that track those gases in the heart and carotid arteries leading to the brainstem. If the breathing pattern in ME/CFS results in low CO2 levels and reduced brain blood flow, breathing these gases should increase CO2 and increase brain blood flow.
  2. Breathing at a rate of 6 breaths per minute for a total of 8 breaths (paced deep breathing). This test is to determine the activity of the rest/digest relaxation reflex (i.e., vagal activity) as compared to the opposing fight/flight stimulated reflex.
  3. Completing a 5-10 minute upright tilt (70 degrees head up on a tilt-table) – this test will stress the autonomic nervous system and enable the researchers to determine whether the breathing retraining has improved autonomic nervous system functioning.
  4. Cognitive testing done before and after will determine if any improvements in cognitive functioning have occurred.

Dr. Edgell reported that thus far, she’s seen low CO2 levels (hypocapnia) in all the ME/CFS participants in the study.

Fibromyalgia and POTS Connection

The Gist

  • Heather Edgell Ph.D.’s Ramsay Grant award is a bit unusual – if successful, her inspiratory muscle clinical trial could provide a home-based, cheap and easy way to improve ME/CFS and long-COVID patients’ health.
  • Inspiratory muscle training (IMT) uses a small device that restricts the airflow in order to increase respiratory muscle strength. It’s been used to improve breathing, overall functioning, sleep, athletic performance, balance, and others in many respiratory diseases, fibromyalgia, heart failure, and in seniors. 
  • Edgell’s study – which will also assess CO2 levels, autonomic functioning, blood flows to the brain, and cognitive performance – hopes to increase CO2 levels in her ME/CFS and long-COVID patients. Low CO2 levels are common in these diseases and can cause an extraordinary number of symptoms, including reduced blood flows to the brain. 
  • Being bedbound can weaken the respiratory muscles and cause shortness of breath and other symptoms. 
  • The breathing retraining – which consists of taking breathes using a small device – occurs three times a week (36 inhalations each day) – and can permanently instill new and healthier breathing patterns. 
  • Similar breathing problems to those found in ME/CFS have also been found in fibromyalgia, postural orthostatic tachycardia syndrome (POTS), and long COVID. Two long-COVID breathing retraining clinical trials have found it helpful. 
  • Edgell’s study should wind up by the end of this year, and publication is expected during the first couple of months of next year. 
  • Breathing retraining devices are relatively cheap ($30-$60), can be purchased online without a prescription, and can be used at home. It may take a month or so to see results. 

Inspiratory muscle weakness has been well documented in FM. Research dating as far back as 1990 was pointing to “respiratory muscle dysfunction” in FM. In 2004, people with fibromyalgia were found to have “inspiratory airflow limitation” during sleep. A 2016 study found lower respiratory muscle endurance, inspiratory muscle strength, and thoracic mobility.)  It was followed by a 2019 study that pointed to a “restriction of respiratory function which in turn may have an effect on physical endurance and work capacity”.

Several fibromyalgia studies found that “breathing exercises” reduced pain, improved functionality, improved sleep, reduced fatigue, etc. Just this year, 12 weeks of respiratory muscle training were found to improve respiratory efficiency and quality of life.

Inspiratory muscle training is old hat in postural orthostatic tachycardia syndrome (POTS), where a 2015 study found it improved heart rate control, and a 2022 study found that a “physiotherapy intervention involving education and breathing control” improved breathing scores. Hyperventilation has been found several times in POTS.


Studies have already begun to assess the effects of inspiratory muscle training in long COVID. One long-COVID study, “Outpatient Pulmonary Rehabilitation in Patients with Long COVID Improves Exercise Capacity, Functional Status, Dyspnea, Fatigue, and Quality of Life“, found that 6 weeks of respiratory training (plus individualized patient education, psychosocial counseling by a psychologist, and nutritional education by a nutritionist) improved exercise capacity, functional status, dyspnea, fatigue, and quality of life at least somewhat. Functional status went up one point on the long-COVID functional scale.

They concluded that “IMT may represent an important home-based rehabilitation strategy” for long COVID. They appeared to use the same protocol (36 inhalations a day, a couple of times a week) as Dr. Edgell’s Solve M.E.-funded clinical trial.

Another large (n=281) long-COVID study, “Inspiratory Muscle Training Enhances Recovery Post COVID-19: A Randomised Controlled Trial“, found clinically significant improvements in breathlessness, respiratory strength, and estimated aerobic fitness.

Check out how to do an in-home test for hypocapnic hyperventilation – A Home Postural Hypocapnic Hyperventilation Test for Chronic Fatigue Syndrome and Fibromyalgia.


As the study has not been finished, Dr. Edgell could not recommend inspiratory muscle training. She did suggest that if you find yourself hyperventilating – breathe into a paper bag for a little while – not for too long.

She should have results by December and expects papers to be out by early 2023. Recruiting people with ME/CFS has been going well but (like some other researchers) she had trouble finding people with long COVID.

Inspiratory Muscle Training at Home

One great thing about IMT is that you can do it at home. The device needed is not particularly expensive and the process is easy to learn. The Respiratory Therapy Zone recommends the following trainers. Since some of them are quite different, it might be worth reading the reviews.

  1. The Breather Respiratory Muscle Trainer – $49.95
  2. POWERbreathe Plus Resistance Breathing Exerciser Trainer – $68
  3. AirPhysio Sports Edition Breathing Exerciser – $69.97
  4. POWERbreathe Plus Fitness Breathing Muscle Trainer – $49.99
  5. AirPhysio Natural Breathing Lung Expansion Exerciser
  6. Breather Fit Respiratory Muscle Exerciser Trainer – $59.95
  7. Expand-A-Lung Sports Breathing Exerciser – $49.90
  8. Voldyne 5000 Volumetric Incentive Spirometer Exerciser
  9. Quest Lung Performance Peak Flow Meter – $23.47

Note that it can take a month or so to begin to see results.

(Health Rising does not receive affiliate commissions from the above links.)

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