RT Journal Article SR Electronic T1 Hormone levels of world class cyclists during the Tour of Spain stage race JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 424 OP 430 DO 10.1136/bjsm.35.6.424 VO 35 IS 6 A1 A Lucía A1 B Díaz A1 J Hoyos A1 C Fernández A1 G Villa A1 F Bandrés A1 J L Chicharro YR 2001 UL http://bjsm.bmj.com/content/35/6/424.abstract AB Objectives—To evaluate the hormonal response to strenuous endurance exercise performed by elite athletes.Methods—Nine professional cyclists (mean (SD) age 28 (1) years; mean (SD) Vo2max 75.3 (2.3) ml/kg/min) who participated in a three week tour race (Vuelta a España 1999) were selected as subjects. Morning urinary levels of 6-sulphatoxymelatonin (aMT6s) and morning serum levels of testosterone, follicle stimulating (FSH), luteinising hormone (LH), and cortisol were measured in each subject at t0 (before the competition), t1 (end of first week), t2 (end of second week), and t3 (end of third week). Urine samples of aMT6s were also evaluated in the evening at t0, t1, t2, and t3.Results—Mean urinary aMT6s levels had increased significantly (p<0.01) during the day after each stage (1091 (33) v 683 (68) ng/ml at t1; 955 (19) v 473 (53) ng/ml at t2; 647 (61) v 337 (47) ng/ml at t3). Both morning and evening aMT6s levels decreased significantly during the study. A similar pattern was observed for morning serum levels of cortisol and testosterone.Conclusions—The results suggest that the basal activity of the pineal gland, adrenal glands, and testis may be decreased after consecutive days of intense, long term exercise. Take home message The night time activity of the pineal gland seems to be attenuated after consecutive days of vigorous daytime exercise, namely three week tour races for professional cyclists. A similar state of exhaustion seems to occur in the adrenal glands and testis.