Perceived fatigue and energy are independent unipolar states: Supporting evidence - B Loy +

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Abstract
Persistent fatigue is a common problem (∼20–45% of U.S. population), with higher prevalence and severity in people with medical conditions such as cancer, depression, fibromyalgia, heart failure, sleep apnea and multiple sclerosis.

There are few FDA-approved treatments for fatigue and great disagreement on how to measure fatigue, with over 250 instruments used in research.

Many instruments define fatigue as “a lack of energy”, thus viewing energy and fatigue states as opposites on a single bipolar continuum.

In this paper, we hypothesize that energy and fatigue are distinct perceptual states, should be measured using separate unipolar scales, have different mechanisms, and deficits should be treated using tailored therapies.

Energy and fatigue independence has been found in both exploratory and confirmatory factor analysis studies. Experiments in various fields, including behavioral pharmacology and exercise science, often find changes in energy and not fatigue, or vice versa.

If the hypothesis that energy and fatigue are independent is correct, there are likely different mechanisms that drive energy and fatigue changes. Energy could be increased by elevated dopamine and norepinephrine transmission and binding. Fatigue could be increased by elevated brain serotonin and inflammatory cytokines and reduced histamine binding.

The hypothesis could be tested by an experiment that attempts to produce simultaneously high ratings of energy and fatigue (such as with two drugs using a randomized, double-blind, placebo-controlled design), which would offer strong evidence against the common viewpoint of a bipolar continuum.

If the hypothesis is correct, prior literature using bipolar instruments will be limited, and research on the prevalence, mechanisms, and treatment of low energy and elevated fatigue as separate conditions will be needed. In the immediate future, measuring both energy and fatigue using unipolar measurement tools may improve our understanding of these states and improve therapeutic outcomes."

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http://www.medical-hypotheses.com/article/S0306-9877(17)31280-X/fulltext

 

I'd just been thinking about the differences between fatigue and energy. I'm able to manage my condition in a way that means my fatigue improves, while my energy does not.

 

My fatigue and energy cap are independent, I feel fatigued as a state, So lets say I sit and feel miserable I want to lay down (not sleepy) but dog tired, I have a few fatigues, the lactic acid one, where there is a lot of pain and achiness, and when I move I feel like burning muscles, and there is the one that my brain feels inflamed, this type I can sleep if I need to. Vs I feel as a normal person and I have no symptoms, but I cannot like stand up and go running even if I wanted to. Some moments I feel so great I think I should stand and exercise and like do this and that, but start to do it and I hit a wall of energy. So for me the lack of energy production is independent of fatigue.

But usually when my fatigue is high, the wall is closer (less expendable energy). But the top number is the top number. So no matter how well I feel I can only do X steps a day. I am one of those that go paralyzed if I overdo.