Trial Report Inspiratory muscle training improves autonomic function in ME/CFS and post-acute sequelae of SARS-CoV-2: a pilot study, 2024, Edgell

https://www.sciencedirect.com/science/article/pii/S1569904824001538

Inspiratory muscle training improves autonomic function in myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of SARS-CoV-2: a pilot study

a
School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
b
Muscle Health Research Centre, York University, Toronto, Ontario, Canada
c
Environmental Health Clinic, Women’s College Hospital, Toronto, Ontario, Canada
d
ICanCME Research Network, Montreal, Quebec, Canada
Received 19 July 2024, Revised 25 September 2024, Accepted 4 October 2024, Available online 6 October 2024.


Highlights

• •
  Inspiratory muscle training (IMT) improves exercise capacity in ME/CFS and PASC
• •
  IMT improves resting heart rate and heart rate variability in ME/CFS and PASC
• •
  IMT improves symptoms of sleep in all groups and pain in ME/CFS
• •
  IMT improves the autonomic symptoms of vascular and secretomotor function in ME/CFS
• •
  IMT should be further investigated as a therapeutic option in these populations

Abstract

Post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are debilitating post-viral conditions with many symptomatic overlaps, including exercise intolerance and autonomic dysfunction.

Both conditions are growing in prevalence, and effective safe treatment strategies must be investigated.

We hypothesized that inspiratory muscle training (IMT) could be used in PASC and mild to moderate ME/CFS to mitigate symptoms, improve exercise capacity, and improve autonomic function.

We recruited healthy controls (n=12; 10 women), people with PASC (n=9; 8 women), and people with mild to moderate ME/CFS (n=12; 10 women) to complete 8 weeks of IMT.

This project was registered as a clinical trial (NCT05196529) with clinicaltrials.gov. After completion of IMT, all groups experienced improvements in inspiratory muscle pressure (p<0.001), 6-minute walk distance (p=0.002), resting heart rate (p=0.037), heart rate variability (p<0.05), and symptoms related to sleep (p=0.009).

In the ME/CFS group only, after completion of IMT, there were additional improvements with regard to vascular function (p=0.001), secretomotor function (p=0.023), the total weighted score (p=0.005) of the COMPASS 31 autonomic questionnaire, and symptoms related to pain (p=0.016).

We found that after 8 weeks of IMT, people with PASC and/or ME/CFS could see some overall improvements in their autonomic function and symptomology.

Keywords
Long COVID
ME/CFS
symptomology
autonomic
inspiratory muscle training


Heather Edgell, Tania J. Pereira, Kathleen Kerr, Riina Bray, Farah Tabassum, Lauren Sergio, Smriti Badhwar,
Inspiratory muscle training improves autonomic function in myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of SARS-CoV-2: a pilot study,
Respiratory Physiology & Neurobiology,
2024,
104360,

 

I wondered whether inspiratory muscle training was GET with cheerleaders. I didn't bother to check the actual exercises for respiratory muscle training, but I do wonder whether they risk triggering PEM.

 

Only glimpsing at the study it looks like they measured a lot of different things, didn't correct for multiplicities and then reported the positive findings in an open label study? Is that standard for how to run such studies? If you don't predefine what your outcome measures are, won't you have to correct for multiplicities in some way?

For an exercise study the authors seem to generally be quite familiar with ME/CFS (which might not be too suprising given that the project was partially funded by the Solve ME/CFS Initiative and Ramsay Research Grant Program). They mention the CCC and also the DSQ but I actually wasn't able to see whether patients were recruited according to any criteria other than "clinically diagnosed with PASC or ME/CFS.", so what were the recruitment criteria and do they include Fukuda etc?

 

6MWD (m)

Controls: 461±62 -> 502±83

PASC: 396±86 -> 398±111

ME/CFS: 343±65 -> 372±60

 

This is where my brain went as well but a google seems to suggest it is referring to a type of breathing exercise. Doesn't seem easy to find information about so I'm not motivated to spend more time looking.

 

This is one of the two device options participants could use: POWERbreathe Plus IMT

I think the exercise is basically making it more effort to inhale.

 

Some Long COVID clinics (US) are having people use this. They possibly suggest other devices also, this is one I know several people have been using.
https://www.pnmedical.com/product/the-breather/

 

Are these p-values for all groups combined? "All groups experienced improvements" makes it seem like each group individually, but it's hard to imagine that tiny difference for PASC was significant with only 7 people.

 

I'm using an IMT device for several years now, 8 mn/ day, it definitively improved my dyspnea, specially at night ( so added benefits of better sleep). I heard about a sensible explanation for that effect: going from an active life to 20h/day in supine position has terrible impacts on thoracic cage and lung muscles/ structure, so IMT exercises help to alleviate those impacts. Worked for me, though real benefits took quite a time to fully materialize (3/6 months )

 

Yes they repeat that in the 3.0 Results section —

Also the SpO2 pre/post 6 min walk is interesting in the PASC group, reformatting —

HC
O2-Pre to post 6MWD (%) pre intervention
98±1 -> 97±2

O2-Pre-Post 6MWD (%) following intervention
98±1 -> 97±3

PASC
O2-Pre to post 6MWD (%) pre intervention
98±1 -> 95±6

O2-Pre-Post 6MWD (%) following intervention
98±3 -> 94±4

ME/CFS
O2-Pre to post 6MWD (%) pre intervention
96±2 -> 96±3

O2-Pre-Post 6MWD (%) following intervention
97±2 -> 96±2

Which seems to indicate that PASC is the only group that has a drop in mean >1%, following 6 min walk, and that this worsens after the IMT intervention.

 

Did they test anyone's 6MWT (or other measures) without intervention?

 

All 3 groups participated in the intervention, there was no non-intervention group.

In the PACE trial, the SMC(no treatment) group mean scores on the 6MWD improved by 22m, to 348m from 326m at baseline.

They say there no difference in age between controls and patient groups when the means are: HC 32, PASC 47, ME 44. Can anyone explain?

 

The sample sizes are so small and there is so much variability in ages that the statistical test used says that it's possible the observed differences are due to chance.

Doesn't seem like the right approach if trying to say ages are the same though... P-value of over .05 doesn't say that they are the same, it just says we can't say they are not the same with the information provided. It seems they should do an equivalence test instead, where the null hypothesis is that they are different.

 

Are you yourself that severe?
Of course don’t necessarily expect an answer as that might be private.

I am asking because I am and on the lookout for things to try. Although I have asthma so that could help out or add unnecessary extra effort…

 

I've done N=1 trials with a class of inspiratory and expiratory training devices (various woodwinds), which suggest they:

• improve diaphragm control significantly
• have no noticeable effect on autonomic function
• result in exactly the amount of PEM you'd expect from the exertion involved

You don't need a device or an instrument to improve breathing and diaphragm control anyway, singing long tones will do it.

But just like the devices mentioned here, it's exercise. Breathing-GET is still GET.

 

Yeah. I thought so. I had to give up yoga breathing exercises for this reason. I’ve also had contact with one of those NHS respiratory physios and to their astonishment I knew how to breathe.

 

I tried out the Powerbreathe and worked up through the lowest levels to find the point at which the training would essentially begin. Once I'd got there, and did the requisite 20 (?) reps, I absolutely could not do them again the next day. I'm going to try again at some point, but with lower reps and at least a day between sessions.

Did you have any problems like this, @nutz ? Did you have to adapt the suggested training protocol?

There are all sorts of benefits claimed for strengthening your diaphragm but I hadn't heard about this one, so thanks for posting, @Dolphin