The Link Between Energy-Related Sensations and Metabolism: Implications for Treating Fatigue, 2022, Filippi et al

[Sly Saint]

Energy-related sensations include sensation of energy and fatigue as well as subjective energizability and fatigability. First, we introduce interdisciplinary useful definitions of all constructs and review findings regarding the question of whether sensations of fatigue and energy are two separate constructs or two ends of a single dimension. Second, we describe different components of the bodily energy metabolism system (e.g., mitochondria; autonomic nervous system). Third, we review the link between sensation of fatigue and different components of energy metabolism. Finally, we present an overview of different treatments shown to affect both energy-related sensations and metabolism before outlining future research perspectives.

https://www.frontiersin.org/articles/10.3389/fpsyg.2022.920556/full

eta: quite a lot on CFS

 

[Trish]

I have skimmed parts of this. I think the most useful part is the attempt in the early part of the article to pick apart different aspects of the sensations of fatigue, energy, fatiguability and energisability, subjective and objective, their measurement, and what different questionnaires are purporting to measure.

The part looking at biological aspects of fatigue and energy seem to me to be limited by the selection of research to highlight, with no attempt to assess the quality of that research. I guess that's a reflection that the authors are psychiatrists, not biomedical scientists. I didn't read all the details in that section.

They seem to be attempting to tease apart the question of whether sensations of fatigue and sensations of energy are opposite ends of the same thing, or are two different phenomena, and to conclude that they are different. So for example you can give a stimulant to someone with MS fatigue, and they feel more energy, but still feel just as much fatigue. That chimes for me with what pwME report that stimulants give a false sense of greater capacity, but if acted on by increasing activity, leads to crashes.

Here's the part of the summary, with extra paragraph breaks added:

Summary and Future Directions
We have presented theoretical and methodological considerations for defining sensations of fatigue and energy, distinguishing between subjective and objective measures, between trait, prolonged state, and state, as well as between different domains of energy-related sensations including cognitive, physical, emotional, motivational, social, and sexual.

We also suggested that the speed through which energy-related sensations arise and dissipate might constitute a further dimension of interest that is currently poorly understood, which we term subjective energizability and fatigability, respectively.

We have also defined sensations of energy as “X sensation of y energy availability related to a task demand,” with X representing state, prolonged state and trait and Y representing the six energy-related domains. While there is robust evidence that sensations of energy and fatigue are two separate constructs, we argue that the acquiescence effect needs to be addressed for conclusions.
[...]

 

[Dolphin]

Fatigue and energy scales don't necessarily measure same thing [in HIV] (Lerdal et al, 2012)
From 2012

"Fatigue and energy measures were moderately correlated with each other in the morning but not in the evening. The concepts of energy and fatigue were inversely related, but not polar opposites in this sample. Fatigue and energy may therefore be distinct constructs that should not be used interchangeably, either in measurement or when interpreting outcomes for research or clinical purposes."

----------------

http://www.psy-journal.com/article/S0165-1781(12)00463-5/abstract


Psychiatry Research

Article in Press

Lee Fatigue and Energy Scales: Exploring aspects of validity in a sample of women with HIV using an application of a Rasch model

Anners Lerdal, Anders Kottorp, Caryl L. Gay, Kathryn A. Lee


Received 24 January 2012; received in revised form 12 July 2012; accepted 26 August 2012. published online 17 September 2012.

Abstract*

This study examines the psychometric properties of the Lee Fatigue and Energy Scales (visual analog version) using a Rasch model application.

The relationship between fatigue and energy is also described for a convenience sample of 102 women with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) who completed the Lee Fatigue and Energy Scales in the morning and evening.

Both scales were assessed for internal scale validity, unidimensionality, and uniform differential item functioning in relation to morning and evening ratings.

Analyses confirmed that both the Fatigue and Energy Scales demonstrated evidence of internal scale validity and unidimensionality.

Mean fatigue measures were also higher in the evening than in the morning and mean energy measures were higher in the morning than in the evening (both p<0.001), indicating that time of day is an important consideration.

Fatigue and energy measures were moderately correlated with each other in the morning but not in the evening.

The concepts of energy and fatigue were inversely related, but not polar opposites in this sample.

Fatigue and energy may therefore be distinct constructs that should not be used interchangeably, either in measurement or when interpreting outcomes for research or clinical purposes.

Keywords: Psychometrics, Measurement, Quality of life, Symptoms, Rasch analysis

 

[Snow Leopard]

This article both lacks conceptual clarity as to the difference between fatigue-related sensations, fatigue, effort, energy-related sensations and how these are mediated physiologically - we know a lot more about how such things are sensed (mediated physiologically) than is stated in the article. For example, they seem to have zero idea about how central fatigue is primarily mediated and it's purpose.