Background: Endocrine system plays a major role in both permissive and regulatory activities in order to adequately respond to physical stress of exercise. But level and direction of activation depend on many factors and are not easily interpreted.
Methods: We tested a group of male professional athletes (21 water polo players and 15 wrestlers), together with 20 sedentary controls matched by age. All participants took a continuous progressive exercise stress test on a treadmill until exhaustion and plateau of oxygen consumption (VO2). Blood samples for cortisol, sex hormone binding globulin (SHBG) and testosterone were drawn in four time points: baseline (B), start of the test (S), point of maximal strain (MAX) and in the 3rd minute of recovery period (R).
Results: Cortisol levels significantly increased in both groups, but the response between S and MAX was more pronounced in controls (p=0.036). The athletes had significantly higher levels of cortisol in all points in test, except during R (p=0.118), when their cortisol levels gradually started to decline. Significant increase in total testosterone was in great deal a consequence of increase in SHBG level (p<0.01 for both). Consequently, calculated free testosterone significantly decreased during test (p=0.008), and the drop was more pronounced in athletes. This was in concordance with significant correlation between SHBG and cortisol level demonstrated in athletes, but not in controls.
Conclusions: It seems that high intensity endurance exercise favors catabolic response, but the level of response highly depends on a previous level of training.
Uvod: Endokrini sistem ima i permisivnu i regulatornu ulogu kako bi se adekvatno odgovorilo na fizički stress prouzrokovan vežbanjem. Ali nivo i smer aktivacije zavise od mnogih faktora i nisu jednostavni za interpretaciju.
Metode: Testirali smo grupu muških profesionalnih sportista (21 vaterpolista i 15 rvača), i 20 sedentarnih kontrola upa renih prema godinama. Sproveden je ergospirome trijski test do iscrpljenosti i platoa potrošnje kiseonika (VO2). Uzorci krvi za određivanje kortizola, vezujućeg globulin seksualnih hormona (SHBG) i testosterona su uzimani tokom 4 vremena: bazno (B), na početku testa (S), u maksimalnom naporu (MAX) i u 3. minutu oporavka (R).
Rezultati: Nivo kortizola je značajno porastao u obe grupe, ali je odgovor između S i MAX bio naglašeniji kod kontrola (p=0,036). Sportisti su imali značajno više vrednosti kortizola u svim tačkama testa, izuzev tokom R (p=0,118), s obzirom da su njihove vrednosti kortizola počele da opadaju. Značajan porast vrednosti ukupnog testosterona je u velikoj meri bio posledica porasta nivoa SHBG (p<0,01 za oba). Posledično, izračunate vrednosti slobodnog testosterona su značajno opadale tokom testa (p=0,008), a pad je bio izraženiji kod sportista. Ovaj rezultat je u skladu sa demonstriranom značajnom korelacijom između SHBG i korti zola kod sportista, ali ne i kod kontrola.
Zaključak: Naši rezultati ukazuju da trening izdržljivosti visokog intenziteta favorizuje katabolički odgovor, ali nivo odgovora značajno zavisi od nivoa utreniranosti.
Keywords: catabolic/anabolic; endurance exercise; sex hormone binding globulin; testosterone.