The distracting role of stress: Impaired executive attention and delayed fatigue perception.
Cognitive stress can impair motor performance and delay fatigue perception during exercise, potentially increasing the risk of injury in high-stress work environments.
Where it sits
this study against the rest of the slu-pp-332 (exercise mimetic) corpusSummary and findings
This study measured the influence of cognitive stress on central fatigue and associated functional changes during exercise in thirty younger adults. Participants performed elbow flexion contractions at 30% of their maximum strength until voluntary fatigue, while their strength, fatigability, and muscle activity were assessed. Results indicated that cognitive stress prolonged endurance despite poorer motor performance.
Abstract
<h4>Background</h4>Acute cognitive stress applied concurrently with fatiguing exercise affects neuromuscular fatigue. However, the underlying central mechanisms in men and women are poorly understood.<h4>Objective</h4>This study aimed to identify the influence of cognitive stress on central fatigue and associated functional changes in the cognitive and motor brain areas in men and women.<h4>Methods</h4>Thirty younger adults, balanced by sex, performed intermittent elbow flexion contractions at a duty cycle of ∼67% at 30% of their maximum strength till voluntary fatigue. Participants' strength, fatigability, and muscle activity were collected. Functional near-infrared spectroscopy was used to monitor the activation of the prefrontal cortex (PFC) and motor cortex (M1) to compute graph-theoretic metrics based on functional integration and segregation in the PFC and M1.<h4>Results</h4>Results indicate that despite poorer motor performance, i.e., lower force steadiness, stress prolonged endurance among both men and women. Stress also stunted the perception of effort for exercise and reduced functional segregation of the PFC. Stress did not contribute to the sex differences in central mechanisms of fatigue.<h4>Conclusion</h4>Our findings suggest that cognitive stress has a distraction effect on higher-order executive attentional resources, resulting in a delayed perception of fatigue and impairing motor performance.<h4>Application</h4>These findings help us understand the psychophysical limitations of workers who are often exposed to high cognitive stress due to high workload conditions. These findings show that a high cognitive load can mask the indicators of exercise fatigue, which may increase the risk of musculoskeletal injury in the long term.
Background
This paper addresses the impact of acute cognitive stress on neuromuscular fatigue during exercise, a topic that lacks comprehensive understanding regarding its central mechanisms in both men and women. Prior research has indicated that cognitive stress can affect physical performance, but the specific effects on fatigue perception and motor function remain unclear. This study aims to fill that gap by exploring how cognitive stress influences endurance and fatigue perception during fatiguing exercise.
Methods
The study employed a controlled design with thirty younger adults, balanced by sex. Participants performed intermittent elbow flexion contractions at a duty cycle of approximately 67% at 30% of their maximum strength until they reached voluntary fatigue. Strength, fatigability, and muscle activity were measured, and functional near-infrared spectroscopy was utilized to monitor activation in the prefrontal cortex and motor cortex.
Results
Results indicated that stress prolonged endurance despite poorer motor performance, specifically lower force steadiness. Additionally, stress was found to stunt the perception of effort during exercise and reduced functional segregation in the prefrontal cortex. No specific numeric findings for primary outcomes were reported.
Interpretation
The findings suggest that cognitive stress can distract from fatigue perception, potentially leading to impaired motor performance. While the results are statistically significant, the clinical significance remains uncertain due to the lack of detailed numeric data and the small sample size. These limitations may confound the conclusions drawn regarding the effects of cognitive stress on fatigue mechanisms.
Key findings
- Stress prolonged endurance among both men and women.
- Stress stunted the perception of effort for exercise.
- Stress reduced functional segregation of the prefrontal cortex.
Limitations
- small sample size of n=30
- no specific numeric findings reported
- did not explore long-term implications of findings
- lacks diversity in participant demographics