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Mental fatigue caused by prolonged cognitive load associated with sympathetic hyperactivity.

Mizuno K, Tanaka M, Yamaguti K, Kajimoto O, Kuratsune H, Watanabe Y - Behav Brain Funct (2011)

Bottom Line: The study group comprised 10 healthy participants.After the 8-hr relaxation session, low-frequency component power (LF), high-frequency component power (HF) and low-frequency component power/high-frequency component power ratio (LF/HF ratio) were not changed from baseline.In contrast, after the fatigue session, the HF and LF/HF ratio were significantly changed from baseline; specifically, the HF was lower and LF/HF ratio was higher as compared to those after the relaxation session.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular Probe Dynamics Laboratory, RIKEN Center for Molecular Imaging Science, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe City, Hyogo 650-0047, Japan. keimizuno@riken.jp

ABSTRACT

Background: It is known that chronic fatigue is associated with sympathetic hyperactivity. However, the relationship between autonomic function and mental fatigue caused by a prolonged mental load in healthy humans is still unclear. Thus, in order to clarify the mechanisms underlying mental fatigue, we examined the association between mental fatigue and autonomic functions.

Methods: The study group comprised 10 healthy participants. To induce mental fatigue, participants performed mental tasks, which consisted of the advanced trail making test, kana pick-out test and mirror drawing test, for 8 hr, corresponding to a normal work day. Autonomic functions were measured by accelerated plethysmography before and after the fatigue-inducing mental tasks. As a control, the same participants completed an 8-hr relaxation session 4 weeks before the fatigue session.

Results: After the 8-hr relaxation session, low-frequency component power (LF), high-frequency component power (HF) and low-frequency component power/high-frequency component power ratio (LF/HF ratio) were not changed from baseline. In contrast, after the fatigue session, the HF and LF/HF ratio were significantly changed from baseline; specifically, the HF was lower and LF/HF ratio was higher as compared to those after the relaxation session.

Conclusions: Sympathetic hyperactivity based on decreased parasympathetic activity is associated with mental fatigue induced by prolonged cognitive load.

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Related in: MedlinePlus

Correlations between visual analogue scale (VAS) value for fatigue and autonomic activities. Low-frequency component power/high-frequency component power ratio (LF/HF ratio; a) log-transformed LF/HF ratio (ln LF/HF ratio; b) obtained on a wave interval analyses using accelerated plethysmography in all the measurement points before and after the 8-hr fatigue and relaxation sessions. Spearman's (a) and Pearson's (b) correlation coefficients and p-values are shown.
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Figure 1: Correlations between visual analogue scale (VAS) value for fatigue and autonomic activities. Low-frequency component power/high-frequency component power ratio (LF/HF ratio; a) log-transformed LF/HF ratio (ln LF/HF ratio; b) obtained on a wave interval analyses using accelerated plethysmography in all the measurement points before and after the 8-hr fatigue and relaxation sessions. Spearman's (a) and Pearson's (b) correlation coefficients and p-values are shown.

Mentions: Correlation analyses between the VAS value for fatigue and the LF/HF ratio or the ln LF/HF ratio in all the measurement points which are before and after the 8-hr fatigue and relaxation sessions are shown in Figure 1. The VAS values for fatigue were positively correlated with the LF/HF ratio (Figure 1a) and the ln LF/HF ratio (Figure 1b).


Mental fatigue caused by prolonged cognitive load associated with sympathetic hyperactivity.

Mizuno K, Tanaka M, Yamaguti K, Kajimoto O, Kuratsune H, Watanabe Y - Behav Brain Funct (2011)

Correlations between visual analogue scale (VAS) value for fatigue and autonomic activities. Low-frequency component power/high-frequency component power ratio (LF/HF ratio; a) log-transformed LF/HF ratio (ln LF/HF ratio; b) obtained on a wave interval analyses using accelerated plethysmography in all the measurement points before and after the 8-hr fatigue and relaxation sessions. Spearman's (a) and Pearson's (b) correlation coefficients and p-values are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3113724&req=5

Figure 1: Correlations between visual analogue scale (VAS) value for fatigue and autonomic activities. Low-frequency component power/high-frequency component power ratio (LF/HF ratio; a) log-transformed LF/HF ratio (ln LF/HF ratio; b) obtained on a wave interval analyses using accelerated plethysmography in all the measurement points before and after the 8-hr fatigue and relaxation sessions. Spearman's (a) and Pearson's (b) correlation coefficients and p-values are shown.
Mentions: Correlation analyses between the VAS value for fatigue and the LF/HF ratio or the ln LF/HF ratio in all the measurement points which are before and after the 8-hr fatigue and relaxation sessions are shown in Figure 1. The VAS values for fatigue were positively correlated with the LF/HF ratio (Figure 1a) and the ln LF/HF ratio (Figure 1b).

Bottom Line: The study group comprised 10 healthy participants.After the 8-hr relaxation session, low-frequency component power (LF), high-frequency component power (HF) and low-frequency component power/high-frequency component power ratio (LF/HF ratio) were not changed from baseline.In contrast, after the fatigue session, the HF and LF/HF ratio were significantly changed from baseline; specifically, the HF was lower and LF/HF ratio was higher as compared to those after the relaxation session.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular Probe Dynamics Laboratory, RIKEN Center for Molecular Imaging Science, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe City, Hyogo 650-0047, Japan. keimizuno@riken.jp

ABSTRACT

Background: It is known that chronic fatigue is associated with sympathetic hyperactivity. However, the relationship between autonomic function and mental fatigue caused by a prolonged mental load in healthy humans is still unclear. Thus, in order to clarify the mechanisms underlying mental fatigue, we examined the association between mental fatigue and autonomic functions.

Methods: The study group comprised 10 healthy participants. To induce mental fatigue, participants performed mental tasks, which consisted of the advanced trail making test, kana pick-out test and mirror drawing test, for 8 hr, corresponding to a normal work day. Autonomic functions were measured by accelerated plethysmography before and after the fatigue-inducing mental tasks. As a control, the same participants completed an 8-hr relaxation session 4 weeks before the fatigue session.

Results: After the 8-hr relaxation session, low-frequency component power (LF), high-frequency component power (HF) and low-frequency component power/high-frequency component power ratio (LF/HF ratio) were not changed from baseline. In contrast, after the fatigue session, the HF and LF/HF ratio were significantly changed from baseline; specifically, the HF was lower and LF/HF ratio was higher as compared to those after the relaxation session.

Conclusions: Sympathetic hyperactivity based on decreased parasympathetic activity is associated with mental fatigue induced by prolonged cognitive load.

Show MeSH
Related in: MedlinePlus