The purpose of this study was to investigate the relationship between changes in vitamin B₁ (B₁) and psychological fatigue after ultraendurance exercise. Serum levels of B₁ (S-B₁) and erythrocyte transketolase (ETK), as well as blood glucose, lactate, free fatty acid, myoglobin, and creatin kinase were measured in 24 Japanese male athletes (37.9±9.2 yrs) who completed triathlon race (3.9km swim, 180km bike, 42.2km marathon). Profile of Mood State (POMS) test was performed for the assessment for psychological fatigue. These tests were conducted two days before, immediately following, and one day after the race. Urinary excretion of B₁ during night was measured one day before and on the race day. Food and supplement records were obtained two days before and on the race day to calculate B₁ intake. Sixteen out of 24 subjects took wore than 2mg 131 by supplement, which is the recommended dosage for endurance sport athletes during training periods (S(＋)group). These 16 athletes were compared with rest of the subjects (S(−) group, n = 8 ). There were no significant group difference in age, physical characteristics, race results, pre- and post-race myoglobin, creatin kinase, or ETK. Mean pre-race S-B₁ of S(−) group was significantly lower than that of S (＋) (p<0.01) and tended to be lower immediately post-race(p=0.086). While, mean change values of S-B₁ were not significantly different between groups. Urinary excretion of B₁ in S(−) group is tended to be lower compared with S(＋) (p=0.076). Mean post-race lactate was significantly higher in S(−) group compared with S(＋). There were no significant group difference in each POMS scores, however prevalence of severe exhaustive state was tended to be higher in S(−) group (p=0.091). The data show that B₁ supplement more than the recommended dosage is related to relatively higher levels of S-B₁, and is suggested to be effective to prevent severe exhaustion after ultraendurance exercise.

DESCENTE SPORTS SCIENCE Vol.18/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE