Did You Know That "Light Physical Activity" Can Be More Fatiguing Than Heavy Weight Lifting?

Low force contractions induce more central fatigue and nervous system fatigue than high force contractions:


https://pubmed.ncbi.nlm.nih.gov/17626289/


This research demonstrates that long duration training of a low or moderate intensity is more taxing to the nervous system.


Mechanistically, this aligns with our understanding of sympathetic activation. A stress state (of varying degrees) occurs during any training, any perceived anxiety-producing trigger, any prolonged activity. The stress hormone production, receptor down-regulation, and therefore CNS fatigue will have more to do with length of activity than load/intensity.


Anecdotally or observationally, the lay audience can confirm this finding. Elite strength athletes are on average more recovered, less anxious, less irritable, less agitated, than non-athletes or elite ultra-endurance athletes. Gym-goers who emphasize short strength training (no matter how heavy) tend to suffer fewer CNS downsides than gym goers who emphasize lengthy routines. Orthopedic injuries (many of which stem from CNS fatigue) occur less in people whose workouts are heavy in load and short in duration than in those people whose workouts are lighter in load and longer in duration.