Mental and physical fatigue-related biochemical alterations.
OBJECTIVE
To confirm fatigue-related biochemical alterations, we measured various parameters just before and after relaxation and fatigue-inducing mental or physical sessions.


METHODS
Fifty-four healthy volunteers were randomized to perform relaxation and fatigue-inducing mental and physical sessions for 4 h in a double-blind, three-crossover design. Before and after each session, subjects were asked to rate their subjective sensations of fatigue, and blood, saliva, and urine samples were taken.


RESULTS
After the fatigue-inducing mental and physical sessions, subjective scores of fatigue were increased. After the fatigue-inducing mental session, the vanillylmandelic acid level in urine was higher and plasma valine level was lower than after the relaxation session. In contrast, after the fatigue-inducing physical session, serum citric acid, triacylglycerol, free fatty acid, ketone bodies, total carnitine, acylcarnitine, uric acid, creatine kinase, aspartate aminotransferase, lactate dehydrogenase, cortisol, dehydroepiandrosterone, dehydroepiandrosterone sulfate, plasma branched-chain amino acids, transforming growth factor-beta1 and -beta2, white blood cell and neutrophil counts, saliva cortisol and amylase, and urine vanillylmandelic acid levels were higher and serum free carnitine and plasma total amino acids and alanine levels were lower than those after the relaxation session.


CONCLUSIONS
Some mental or physical fatigue-related biochemical changes were determined. Various biochemical alterations reflecting homeostatic perturbation and its responses might be shown. We believe that our results contribute to clarifying the mechanism of fatigue, developing evaluation methods, and establishing a basis for treatment.
Nozaki
Satoshi
S
Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan. satoshi.nozaki@hotmail.co.jp
Tanaka
Masaaki
M
Mizuno
Kei
K
Ataka
Suzuka
S
Mizuma
Hiroshi
H
Tahara
Tsuyoshi
T
Sugino
Tomohiro
T
Shirai
Tomoko
T
Eguchi
Asami
A
Okuyama
Kaori
K
Yoshida
Kaoru
K
Kajimoto
Yoshitaka
Y
Kuratsune
Hirohiko
H
Kajimoto
Osami
O
Watanabe
Yasuyoshi
Y
D000328:Adult; D001774:Blood Chemical Analysis; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005221:Fatigue / Q000097:blood / Q000378:metabolism* / Q000503:physiopathology* / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D005222:Mental Fatigue / Q000097:blood / Q000378:metabolism* / Q000503:physiopathology* / Q000652:urine; D018763:Muscle Fatigue / Q000502:physiology*; D012063:Relaxation / Q000502:physiology*; D012463:Saliva / Q000737:chemistry; D013997:Time Factors; D016482:Urinalysis