Perceived Time Shapes Physical Fatigue Accumulation and Its Neural Oscillatory Correlates 2026 Matta et al

[Andy]

Recent studies suggest that fundamental physiological processes, such as physical fatigue, rely on perceived rather than actual time. However, the neural correlates underlying this effect and its disentanglement from motivational factors (i.e., performance goals) remain unknown. To investigate the time deception effect on fatigue, we developed a novel EEG design in which participants (N = 24) performed 100 isometric contractions at a fixed pace and resistance in four distinct sessions. The actual contraction duration (short or long) and the calibration of the displayed clock (normal or biased toward acceleration or deceleration) were independently manipulated across sessions to examine whether fatigue and its neural correlates evolved in response to perceived or actual time.

Our results showed a slowed-down accumulation of physical fatigue when the clock was slowed down, irrespective of motivational factors, while no symmetric effect was observed when the clock was accelerated. This time-deception effect was accompanied by frontal oscillatory dynamics that closely tracked perceived rather than actual time, while motor-related activity showed no such modulation. Further analyses highlighted the key role of frontal oscillatory dynamics in the effectiveness of the time-deception effect on physical fatigue.

Open access

 

[Jonathan Edwards]

This seems relevant to discussions previously about fatigue involving integration over accumulated signals. I don't know how good the methodology is but it sounds like a sensible experiment. The asymmetry is interesting.

 

[wallfish]

The title and abstract remind me of a replication crisis blog that critiqued a paper that claimed something along the lines of "wounds heal faster when participants are looking at a sped-up clock". I don't quite remember the source and don't seem to find it back right now.

 

[Eleanor]

So they seem to have found that muscles behave in a less fatigued way when the brain perceives less time has passed, but they don't behave in a more fatigued way when the brain perceives more time has passed. Not sure how this relates to real-world activities where people aren't constantly looking at a clock and getting beeps and flashes to tell them to start or stop moving.

And my usual question when reading conclusions which rest on data that has been crunched and averaged out in this way: is this an effect that is seen reliably in all participants? Or is there actually a lot of variation between individuals?

 

[Jonathan Edwards]

So they seem to have found that muscles behave in a less fatigued way

I am not sure they are suggesting that muscles behave differently. The perception of fatigue is less. As far as I know they are not testing for muscle fatiguability.

I suspect it translates reasonably well to real life because we have pretty good clocks built in. We can judge that something took 'too long' even if we cannot say how many clock units of time too long. We have to do that to follow music (in a shorter time frame).

It certainly fits with my experience that prolonged travel makes my clock seem to advane an hour, irrespective of time zone changes. Except that that would be an example of what they did not find (more tired when the clock sped up).