Image description: The picture shows a hand writing in a diary. An apple I -watch is shown on the person's right wrist. Two smaller pictures inset show people with ME/CFS. ME Association Logo (bottom right) The title reads: America: Rethinking fatigue: Feeling tired vs. being physically depleted

America: Rethinking fatigue: Feeling tired vs. being physically depleted

A study suggests that perception of fatigue differs from physical fatigue, and this difference could lead to better treatments. Fatigue affects the health and quality of life for many people, but there are few effective treatments for it, experts say. Now new research suggests that redefining fatigue, and understanding how a brain region known as the cerebellum processes fatigue, may hold clues for better treatment.

The Washington Post by Sam Jones

Research by Pablo Celnik and his colleagues at Johns Hopkins University shows that performance fatigue, also known as “fatigability” — an objective measurement of a person’s ability to do a physical or cognitive task — can be different from the perception of fatigue — a person’s subjective assessment of the fatigue they feel.

Using more specific language — fatigability vs. perception of fatigue — to describe experiences of fatigue can be helpful in devising treatments, the researchers say. Fatigue is “a very significant, common problem in patients with neurological conditions,” but “it is very poorly understood,” said Celnik, a professor and director of the physical medicine and rehabilitation department at Johns Hopkins University.


“The findings represent incremental progress in understanding how we experience and regulate fatigue,” said Brian Walitt of the National Institutes of Health. Walitt studies the clinical and biological characteristics of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). But “as only healthy volunteers were part of this study,” said Walitt, who was not involved in the study, “it does not provide any direct insight into medically fatiguing conditions.”

Casamento-Moran is taking that next step. With what she and her colleagues learned from this new research, Casamento-Moran is studying perception of fatigue in people with long covid, probing “why they feel the way they feel” and how that impacts their cognitive and motor abilities, she said.

Coping with fatigue

Based on these findings and other work the researchers have done related to fatigue, they recommend these strategies for people suffering from fatigue:

  • Use a “pacing” strategy. With pacing, patients conserve energy the best they can by limiting their activity.
  • Avoid trying to learn new information when fatigued. In a 2019 study, Celnik and collaborators found that when healthy participants performed a task that caused muscle fatigue (fatigability), and then were asked to learn a new physical skill, they did poorly compared with participants who were not experiencing muscle fatigue. In addition, it was harder for them to learn that new movement in the following days, suggesting that working past performance fatigue to learn a skill is counterproductive. Not only will you not learn as well in the moment, Celnik said, it could also negatively impact your ability to learn a new skill even days later.
  • Be kind to yourself. Casamento-Moran says the field is progressing and hopes there will be more concrete advice and rehabilitation treatments, but there are still many intricacies concerning fatigue that experts don’t understand. “So if you’re tired, be nice to yourself. Take a break,” she said.
Energy Management & Pacing
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