Dane Cook's analysis of exercise data of the CDC's MCAM study

[dratalanta]

I was told aged around 23 that my lung capacity was very small. The nurse at the GP surgery got quite ratty with me about it, and said I wasn't trying hard enough to breathe deeply (obviously not the case). I was surprised, since at that time I was mild/moderate and still quite active. I concluded it was likely a breathing pattern I had developed in response to having already had ME for years (ME since early childhood).

Breathing exercises, including breathing meditation, have always been impossible for me as sticking to an externally imposed breathing schedule triggers PEM, even when I was healthy enough to walk, do yoga etc. My body has a strong sense of how it wants to breathe, and doesn't appreciate me trying to "improve" that.

 

[Blueskytoo]

Breathing exercises, including breathing meditation, have always been impossible for me as sticking to an externally imposed breathing schedule triggers PEM, even when I was healthy enough to walk, do yoga etc. My body has a strong sense of how it wants to breathe, and doesn't appreciate me trying to "improve" that.

One of the weird things I noticed right from the start when I got ill was that I could no longer sing along to music as I couldn’t hold my breath for long enough. It’s got better over the last twelve years or so, but I still can’t hold my breath for more than about ten to fifteen seconds, and deep breathing exercises and yoga-type breathing make me feel really panicky and lightheaded if I do them for more than just a couple of breaths.

I also notice that I not only breathe more shallowly than my husband, to the point where it’s sometimes hard to see my chest move, but I breathe more slowly when awake than he does while he’s asleep. My watch measures my respiration rate and usually has me at about 8 breaths per minute.

 

[Louie41]

My experience is almost identical.

 

[alex3619]

Did this become more apparent/pronounced on the second day or was this based on a single CPET?

Without repeat CPET this data is much less useful. So this question is important.

 

[alex3619]

It was a single CPET study. There was also some mention of cognitive testing by Unger, so perhaps we'll see an effect of a single CPET on cognitive function.

Then many conclusions from the data are potentially questionable. We have long known a single CPET does not show the prototypical problem.

 

[Ryan31337]

One of the weird things I noticed right from the start when I got ill was that I could no longer sing along to music as I couldn’t hold my breath for long enough. It’s got better over the last twelve years or so, but I still can’t hold my breath for more than about ten to fifteen seconds, and deep breathing exercises and yoga-type breathing make me feel really panicky and lightheaded if I do them for more than just a couple of breaths.

This would get you a hyperventilation syndrome diagnosis pretty quickly in clinics. Its pretty textbook. Forced hyperventilation screens are basically what you describe, taking deep breaths to provoke symptoms whilst watching an etCO2 monitor connected to a nasal cannula - if you're chronically hyperventilating you'd expect to see lower resting etCO2, a rapid drop and then slower recovery after. Respiratory physio's also use breath holding exercises as a way to recognise/retrain your breathing, I've seen figures of holding <30 seconds being considered abnormal, though I suspect this might change for holding before or after exhalation.

The problem is when the assumption is made that the hyperventilation is simply a result of an anxiety disorder, rather than having a complex underlying physiological/metabolic cause. But isn't that the same with everything...

 

[Snow Leopard]

Why is a comparison of VE to controls useful in knowing if patients are hyperventilating? Isn't the ratio of VE to CO2 the important factor? If the patient is producing less CO2 for the same VE they will be relatively hyperventilating?

VE/VCO2 is not unitless ratio. Instead, it is a rate. Minute ventilation (VE) is ml/minute, the other is just volume of CO2 exhaled in ml.

VCO2 was not increased compared to controls (it was actually lower compared to unmatched, so there was no relative hypocapnia as would be expected if there was hyperventilation. With VE and VCO2 being similar, it is hard to argue this is hyperventilation.

 

[Snow Leopard]

I suggest the deeper breathing may be a positive (central) adaptation to ongoing Group III and IV muscle afferent signals.

(this also means I don't expect to see it in all patients)

The physiological effects of slow breathing in the healthy human
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5709795/

Interestingly, it has been shown that controlled slow respiration at 6 breaths per min in healthy humans reduces the chemoreflex response to hypercapnia and hypoxia, compared with spontaneous respiration or controlled respiration at 15 breaths per min [21].

 

[Tia]

Well this is interesting. Just timed myself out of interest and I do about 6 deep breaths per minute (slightly under actually).

 

[Yvonne]

He said that these ventilatory responses suggest poor perfusion and a problem with gas exchange.

”

Perfusion, perfusion, perfusion ...
IMO poor perfusion is the key to understanding the symptoms of ME. All (or most) physiological processes work normally, but are under-resourced because of poor perfusion. (I hope to write this up properly at some point).