Excessive fatigue, exertion, and so on are nuisances limiting daily activities

October 1st, 2014 by Phil Weiser Leave a reply »

Summary: List blog topics that will help prepare review for a journal about fatigue.

Student: You have been invited to write a review about Fatigue and RPE. Congratulations!

Professor: Thank you, Simone Cairns of Auckland University of Technology, New Zealand for setting up the invitation. The actual invitation came from Fred Friedberg, for his journal: “Fatigue: Biomedicine, Health & Behavior”

And its temporary title is, “How can our perceptions become factors limiting prolonged performance?”

Student: First of all, what do you do this summer?

Professor: Anne and I spent a wonderful week at Lake Dunmore visiting with her Vermont son and his family. Below is an evening photo from the dock with canoe and kayak below the cottage.

Dock on Lake Dunmore

Dock on Lake Dunmore

Student: Well did you do anything related to exercise science?

Professor: Yes. I did get in some interesting reading about:

  • High Intensity Interval Training (HIIT, Ref. 1); my brother, Karl, mentioned this to me. I discovered that this has become my preferred exercise mode since I was about 60 years old, about 12 years ago!
  • Fatigue and Fatigability; Enoka (Ref. 2) helped me bridge my conceptual gap that existed between acute and chronic fatigue.
  • Talk Test (Ref. 3); hey, I used this with cardiac and pulmonary patients 30+ years ago to avoid talking to themselves in paragraphs and not exercise hard enough.
  • Pacing and decision making; a recent review by Smits, Pepping, & Hettinga (Ref. 4) validated my concepts about perception merging into action by using Cizek’s Affordance Competition Hypothesis (e.g., see Sensory Processing Part 2).

Student: And what are your proposed topics for Fall 2014?

Professor: First I suggest we review the following:

  • What limits the ‘mix’ of perceptions that one experiences?
    • Reticular thalamic sensory gates do not allow passage of ‘unwanted’ info and
    • Use of ‘searchlight’ by posterior insula during body scan to change ‘mix.’
  • How are the intensities of perceptions estimated and reported?
    • Anterior-middle insula estimates the magnitude of the intensity, and
    • Internal talk sets up the reporting of symptom intensity.
  • How do I
    • process my perceptions,
    • select my actions from predictions of possible outcomes, and
    • report my symptoms?

  • Well, I can use the Six Stages of Perceptual Processing

with the first five stages shown below and provided by Menon and Uddin (Ref. 5) and

Menon Uddin 2010 Fig 5

 Figure 3 from Menon & Uddin, Ref. 5

  • with the sixth stage for symptom reporting added in my last post (Sensory Processing Last Part) (see Ref. 6 for background on question interpreting and Ref. 7 for internal speech production modeling).

Student: Great start of a list. I was a bit confused about these key concepts when I reread your posts from spring and summer.

Student: But how will you use the next posts in preparing the review on Fatigue and RPE?

Professor: The additional blog posts will explore topics that will be in the Fatigue Manuscript to:

  • Review limiting factors that lead up to ‘task failure’ or decline in ‘activities of daily living;’
  • Review definitions for overall fatigue and exertion, as well as aversion, exhaustion, and other key nuisances limiting activity;
  • Explore how changes in symptom processing during prolonged exercise interact with critical cortical, subcortical, and peripheral neurophysiological and metabolic processes, and
  • Look in a Crystal Ball for the important present and future areas of research and real-world applications for measuring fatigue and overall exertion.

Take Home Point: Now the Fall 2014 series is started that leads to a manuscript written as a review.

Next: How come we are not overwhelmed by all our sensations?


  1. Gillen JB, Gibala , MJ. (2014) Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness? Appl Physiol Nutr Metab 39: 409– DOI: 10.1139/apnm-2013-0187.
  2. Enoka RM. (2012) Muscle fatigue – from motor units to clinical symptoms. Journal of Biomechanics 45: 427–433. DOI: 10.1016/j.jbiomech.2011.11.047.
  3. Lyon E, Menke, M, Foster C, Porcari JP, Gibson M, Bubbers T. (2014) Translation of incremental talk test responses to steady-state exercise training intensity. J Cardiopulm Rehab Prev 34: 271–275.
  4. Smits BLM, Pepping G-J, Hettinga FJ. (2014) Pacing and Decision Making in Sport and Exercise: The Roles of Perception and Action in the Regulation of Exercise Intensity. Sports Med 44: 763–775. DOI: 10.1007/s40279-014-0163-0.
  5. Menon V, Uddin LQ. (2010) Saliency, switching, attention and control: a network model of insula function. Brain Struct Funct 214: 655–667. DOI: 10.1007/s00429-010-0262-0.
  6. Specht K. (2014) Neuronal basis of speech comprehension. Hearing Research 307:121-135. DOI. 10.1016/j.heares.2013.09.011.
  7. Hickok G (2012) Computational neuroanatomy of speech production. Nature Reviews Neuroscience 13: 135-145 DOI: 10.1038/nrn3158.


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