Exercise augments the nocturnal prolactin rise in exercise-trained XXXX .

@entity1 @entity227 @entity2613
OBJECTIVE: The objective of this study was to profile over a 24 h period the prolactin responses of exercise-trained @entity1 on a day involving rest with no exercise in comparison to a day involving exercise training sessions. METHODS: This is a quasi-experimental design study using repeated measures determination of 24 h prolactin responses in exercise-trained @entity1 (n = 16; age = 27.3   3.3 years (mean    standard deviation)). Blood samples were taken hourly over a 24 h period on a day involving two intensive exercise training sessions ( @entity2613 ), and on a separate @entity227 ( @entity227 ) with no exercise activity. The order of the @entity2613 and @entity227 was randomized. Physical activity and diet were controlled and replicated for the @entity2613 and @entity227 . Blood specimens were handled, prepared and analyzed utilizing appropriate standard clinical practices. The data were analyzed with the Friedman analysis of variance and Nemenyi post hoc statistical procedure for repeated measures. RESULTS: On the @entity227 , prolactin displayed a typical circadian rhythm with daytime values of the hormone being less than the nocturnal rise once sleep had begun (p < 0.05; 16:00-20:00 h > all other times). On the @entity2613 , prolactin responses were noticeably different from those of the @entity227 . The morning and afternoon exercise sessions included significant increases in prolactin immediately at the end of the exercise sessions, being greater than corresponding @entity227 time points (p < 0.01; 01:00 h and 10:00 h); also for the second hour (2 h) following the morning exercise session. On the @entity2613 there was a displayed circadian nocturnal response in the hormone with 16:00-24:00 h being elevated above the all nonexercise effected values for that specific day (p < 0.01). Finally, the @entity2613 nocturnal elevation for prolactin for 16:00-24:00 h was significantly greater than the same respective hours on the @entity227 (p < 0.05). CONCLUSION: Findings clearly demonstrated that nocturnal prolactin responses are augmented in exercise-trained @entity1 on days when they perform exercise. The mechanisms inducing this adaptive response are unclear but warrant further investigation.
