...(PPG)-determined heart rate variability (HRV) & extracellular water (ECW) in the evaluation of chronic stress & inflammation, 2022, Chrousos et al

Full title: Photoplethysmography (PPG)-determined heart rate variability (HRV) and extracellular water (ECW) in the evaluation of chronic stress and inflammation

Background
Heart rate variability (HRV) is the physiological variation in the time interval between consecutive heartbeats. Extracellular water (ECW) is the aqueous compartment surrounding cells and has been used as an inflammation index. Medically unexplained symptoms (MUS) refer to persistent psychosomatic bodily complaints, and their presence may be employed as a clinical index of chronic stress and inflammation, useful in distinguishing suffering patients from healthy subjects.

Aim
To evaluate the clinical performance of SDNN (standard deviation of intracardiac beat time interval of normal sinus beats) and RMSSD (square root of the mean squared differences of successive NN intervals) as indices of HRV, and their correlation with ECW and MUS.

Patients and methods
A large multicenter retrospective study was conducted in 37 Italian medical practices in Caucasian men and women aged 20 to 70 years. SDNN and RMSSD were measured with the PPG Stress Flow® device (BioTekna, Italy), while ECW was determined with the BIA-ACC® device (BioTekna, Italy). All subjects filled in a MUS® questionnaire with 19 “nonspecific” symptom questions. The study sample was stratified by decade of age into five groups.

Results
Data from 9246 subjects comprising 3127 males and 6119 females, with a median age of 47 years, were analyzed. HRV index SDNN and RMSSD distributions in the entire sample and in each of the five age groups were significantly greater in subjects with a limited number of MUS (0–5) than in subjects with six or more symptoms, while both distributions correlated negatively with ECW.

Conclusion
SDNN and RMSSD and ECW were predictors of MUS and were successfully used to objectively evaluate chronic stress and inflammation.

Paywall, https://link.springer.com/article/10.1007/s42000-021-00341-y

 

They assume that our incredibly powerful thoughts are causing those changes of course.

 

Yes, I've had this thought for a while now that even when an unshakeably good biomarker is found, they will just say: "But they do that with their mind!"

 

This looks like a potentially useful study that ends up being mostly useless because of poor and biased analysis. Unfortunately some of the choices they make pretty much render it a waste. Even when they find objective findings, they still argue their prior beliefs. The beliefs are supreme and must be coddled and encouraged at every opportunity.

ECW is interesting. Inflammation increases water in tissue, which must be cleared by the lymphatic system. This extra water in organs means less for the circulatory system, and may itself explain some of the symptoms, such as headaches, dry mouth, etc. As they say, it's a common feature of inflammation. Without that process tissue would swell up, so the lymphatic system must be working hard here.

So that makes two interesting objective findings, but because their starting point was psychosomatic woo and chronic stress, which cannot be evaluated and means absolutely nothing in this context, this is all they can think of.

Hopefully someone less blatantly biased takes it from here. It's ironic that in almost every case of "stress", the real answer is probably inflammation anyway, or more generically immune activation. It's just that they had to slap on the label of stress because it always is. What a wasted opportunity.

 

In reading this there is a big problem in what is NOT said.

If this research does indicate what they have reported it seems that using the term MUS is misleading. Ad they mean MUS to be psychologically driven illness who's cure we are all well acquainted with. But, there is nothing at all indicating that forgone conclusion.

The only thing we can draw from this is what's stated in the results. The conclusion comes out of thin air. The researcher's have NO proof of their conclusion resulting from the psychological.

It's not only do they have no proof. They know they cannot prove it.

It's as usual. Even with possibly interesting data that might reveal something more about the illness they immediately put it in the service of unfalsifiable beliefs.

All because 'the mind affects the body' is their mantra. Can that be any more vague. After all this interplay works in both directions. The body affects the mind. But the power of control lies with the mind for BPS and it is preeminent.

And while there are attempts to enlarge their influence to physical disease where the reason is known they can only ever do so as the 'secondary' influence.

Only the medically unexplained (MU) gives them a loop-hole to make sweeping claims about the preeminence of thinking causing illness. As each MU illness is better understood it gets shifted to the biology as primary influence.

And yet the BPS believers will never concede. They are infatuated with the idea of controlling all with the power of the mind. And that idea has been up front main-stream media fantasy for quite some time. And I think at it's heart is -- fear.

 

To people running around in circles, the beginning and the end are the same thing.

 

I agree their work is entirely circular. And although not strictly the topic of this thread I am beginning to think that is because the research is not at all the point.

A lot of the funding (not all) of these seriously goofy studies comes directly from the university or universities that employ the person(s). And so long as they are allowed to mark their own homework as you and others have pointed out then their work is always 'brilliant' and always 'more research is needed'.

This has the effect of increasing the prestige of the institution. And this acts as a magnet for international students tuition money and as advertising for fundraising -- also a nicely closed loop. Set yourself up as world class by marking your work as brilliant and then tell everyone you're brilliant and watch the money come in. IMO at present I'm thinking this is the whole point.

The fact that some BPS cabalists found fertile ground for goofball research that no one would question is ironically perhaps a kind of brilliance.