Central nervous system fatigue alters autonomic nerve activity

Area of Science:

• Physiology
• Neuroscience
• Psychology

Background:

• Fatigue is a prevalent symptom in contemporary life.
• Understanding the mechanisms of fatigue is crucial for public health.
• Autonomic nervous system (ANS) activity plays a role in physiological regulation.

Purpose of the Study:

• To investigate the relationship between central nervous system (CNS) fatigue and autonomic nerve activity.
• To elucidate the physiological changes associated with experimentally induced fatigue.

Main Methods:

• Twenty healthy participants underwent a 30-minute 2-back test to induce fatigue.
• The Advanced Trail Making Test (ATMT) was administered before and after fatigue induction to assess performance.
• Electrocardiograms (ECG) were continuously monitored to analyze autonomic nerve activity via R-R interval analysis.

Main Results:

• Task performance on the ATMT, measured by trial number and error counts, declined post-fatigue.
• While 2-back test performance remained stable, ECG analysis revealed a decrease in high-frequency (HF) power.
• The low-frequency (LF)/HF power ratio showed an increasing trend, indicating altered autonomic balance.

Conclusions:

• Experimentally induced CNS fatigue is associated with a significant shift in autonomic nerve activity.
• Specifically, decreased vagal nerve activity (indicated by reduced HF power) and increased sympathetic nerve activity (indicated by elevated LF/HF ratio) were observed.
• These findings contribute to understanding the physiological basis of fatigue and its impact on the autonomic nervous system.