Endocrine response to intense interval exercise.

This investigation provides an insight into the physiological changes produced, and processes operating, during and after a typical interval exercise training regime. The role of interval exercise in the modulation of the plasma concentration of sex hormone binding globulin (SHBG) and the hormones beta-oestradiol, testosterone, prolactin and growth hormone was assessed. Eight trained male athletes [mean maximal oxygen uptake (VO2max) 64.3 (SD 3.8) ml.kg-1 x min-1, mean age 31.5 (SD 4.5) years] undertook an intense interval exercise (treadmill running) protocol to exhaustion. Subjects completed an average of 15.6 x 1-min runs. This interval protocol produced significant increase in the plasma concentration of SHBG and all four hormones (all P < 0.01) in the immediate post-test period. The plasma concentration of the hormones increased as indicated: beta-oestradiol (45%), testosterone (38%), prolactin (230%), growth hormone (2000%). These hormones have an established capacity to interact with components of many physiological systems and, as such, may provide a mechanism for the changes induced by intense exercise in many of these systems.