Influence of training on the response of androgen plasma concentrations to exercise in swimmers

In eight top-level male endurance swimmers the aerobic performance and the response to exercise of total testosterone (T), free testosterone (fT), sex hormone binding globulin (SHBG), non-SHBG-bound testosterone (NST) and cortisol (C) were evaluated during a training season. The swimmers participated in three test sessions which occurred 6, 12 and 24 weeks after the beginning of the season. During each session, after a standard warm-up, the swimmers performed a set of 15 x 200-m freestyle, with a 20-s rest between repititions, at a predetermined individual speed. Three blood samples were collected: before warm-up, at the end of the set, and after 1 h of recovery. A few days before each session, the individual swimming velocity associated with a 4 mmol.l-1 blood lactate concentration (v4) was assessed as a standard of aerobic performance. The values of v4 were lower in the second session than in the third one. The concentrations of C. which increased after the exercise, showed the highest values in the second session. The values of T and the T:SHBG ratio increased after the exercise but returned to their initial concentrations during the recovery period. The values of fT and NST increased after the exercise in the first and third sessions. In the initial two sessions, when the aerobic performance was still low, the concentrations of NST decreased to below the initial values after recovery. In session III, when the adaptation to the training workload was complete, NST returned to resting concentrations after recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Responses of atrial natriuretic peptide and other fluid regulating hormones to long distance swimming in the sea

The plasma hormonal response following a swimming competition in the sea (18 km) was evaluated in 12 top level male endurance swimmers. At the end of the effort, while plasma renin activity (PRA) and aldosterone concentration (ALDO) were unchanged, a significant increase in plasma atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) concentrations were recorded. These changes were associated with a decrease in haematocrit and an increase in Na+ and Cl- plasma concentrations. The individual variations of ANP (difference between the final and initial concentrations) were inversely correlated with the corresponding individual variations of PRA and ADH. The results suggest that, during prolonged swimming, ANP may exert an inhibitory effect on the PRA-ALDO axis and have a modulatory role with regard to ADH secretion.

Blood lactate accumulation in top level swimmers following competition

The purposes of this study were to evaluate the significance of blood lactate values after competitions and the blood lactate-swimming speed relationship to swimming performances. Auricular blood samples (N = 421) were collected in 203 top level Italian swimmers (116 males and 87 females) at the end of competitions performed in a 25 m swimming pool. The distribution of all lactate values differed between males and females. The lowest lactate values occurred in swimmers performing the longest distances both in males (1500 m) and females (800 m). In swimmers performing freestyle events a relationship between V-4 mM (swimming speed at 4 mmol/l blood lactate value) and competition velocities was observed, in males, at 200, 400 and 1500 m and, in females, at 400 and 800 m. The predicted velocity corresponding to the competition lactate value assessed by the individual blood lactate-swimming speed relationship was found to be highly related to the actual competition velocity. Results suggest that blood lactate values in swimmers are a useful indication of individual aptitudes.

Changes in the exercise-induced hormone response to branched chain amino acid administration

It was the aim of the present experiment to detect possible effects of branched-chain amino acids (BCAA) on the endocrine response to 1 h of continuous running. Blood samples were collected from 14 long-distance runners (age 24-42 years) in two different trials performed at 1-week intervals. In both trials (E and P) blood samples were collected at the following times: 9 a.m. (basal values sample), 10.30 a.m. (sample 90), 11.30 a.m. (sample 150), 12.30 p.m. (sample 210); the athletes performed 1 h of running at a constant predetermined speed between samples 90 and 150. Following the basal sample a mixture containing BCAA (E trial), or not containing BCAA (P trial) was ingested. In both trials no hormone basal concentrations, except insulin, were changed before exercise. In P trial, following exercise (sample 150), human growth hormone (HGH), prolactin (PRL), adrenocorticotropic hormone (ACTH) and cortisol (C) increased, while testosterone (T) decreased. In sample 210, after 1 h of rest, while ACTH, PRL and HGH had recovered to basal concentrations, C remained elevated and T displayed a further decrease. In the E trial a similar pattern of change was observed in sample 150 for HGH, PRL, ACTH and C; in sample 210 HGH and PRL displayed significantly lower values than in the corresponding P trial samples. The T was not modified by the running exercise and increased during the recovery period. It is, therefore, suggested that BCAA administration before exercise affects the response of some anabolic hormones, mainly HGH and T.

Hormonal changes after supine posture, immersion, and swimming

This study was undertaken to evaluate the effects of the supine posture, immersion, and swimming on hormones involved in the regulation of hydrosaline equilibrium. Plasma levels of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), plasma renin activity (PRA), and aldosterone (ALDO) were measured by radioimmunoassay in eight untrained young subjects (five males and three females). Blood samples were collected on different days: control morning samples in a relaxed standing posture before each test; after 20 min in a supine position; after 20 min of horizontal immersion in water at 28 degrees C; after 20 min of backstroke swimming (speed about 1 m/s). No changes occurred in AVP levels after each test. ALDO and PRA increased significantly only after swimming and were directly correlated. ANP increased significantly after immersion, but no further increase was observed after swimming. The hematocrit, which increased after swimming, was inversely correlated with ANP levels in the post-exercise samples. These data show that while ALDO and PRA increase only in response to swimming, even at moderate intensity, ANP probably requires more prolonged and intense exercise to reach a significantly higher level than in immersion.

Anaerobic threshold in runners and cyclists

Two different noninvasive procedures have been used to determine the anaerobic threshold (AT) in 15 long distance runners and in 6 cyclists. The AT values obtained by ventilatory methods (on treadmill for runners and on cycloergometer for cyclists) and the AT values obtained by a field test were significantly correlated.

Hormonal and metabolic effects following a football match

Hormonal and metabolic parameters were studied for two teams after a football match. Blood samples were collected before the start, at half-time, at the end, and 45 and 90 min after the end of the game. In the first team, ACTH, cortisol, and lactate levels increased significantly during the whole match to resume basal levels in the fourth sample (45 min after the end of play). HGH, prolactin, and blood glucose were found to be increased only at half-time. The second team had an intense and long warm-up period before the match and the lactate concentrations were already elevated in the first sample. All the other parameters, except ACTH and glucose, displayed a pattern similar to that of the first team. The differences in the time courses of the hormonal and metabolic values are discussed.

Androgen levels following a football match

In 18 trained football players, blood samples were collected before a football match, at half-time, at the end, and 45 and 90 min after the end of the match. The testosterone (T) level showed a decrease in the rest period. Dihydrotestosterone (DHT) increased during the match, but returned to initial levels in the last samples. The T/DHT ratio decreased, reached the minimal value at the end of the exercise, and returned to basal levels in the rest period. Cortisol and androstenedione levels increased during the match, but returned to control levels 45 and 90 min after the end of the match, respectively. It is suggested that during this type of exercise anabolic and catabolic hormones may be simultaneously activated.