Threshold increases in plasma growth hormone in relation to plasma catecholamine and blood lactate concentrations during progressive exercise in endurance-trained athletes.
Plasma human growth hormone ([HGH]), adrenaline ([A]), noradrenaline ([NA]) and blood lactate ([La-](b)) concentrations were measured during progressive, multistage exercise on a cycle ergometer in 12 endurance-trained athletes [aged 32.0 (SEM 2.0) years]. Exercise intensities (3 min each) were increased by 50 W until the subjects felt exhausted. Venous blood samples were taken after each intensity. The [HGH] and catecholamine concentrations increased negligibly during exercise of low to moderate intensities revealing an abrupt rise at the load corresponding to the lactate threshold ([La-]-T). Close correlations (P <0.001) were found between [La-]b and plasma [HGH] (r = 0.64), [A] (r = 0.71) and [NA] (r = 0.81). The mean threshold exercise intensities for [HGH], [A] and [NA], detected by log-log transformation, [154 (SEM 19) W, 162 (SEM 15) W and 160 (SEM 17) W, respectively] were not significantly different from the [La-]-T [161 (SEM 12) W]. The results indicated that the threshold rise in plasma [HGH] followed the patterns of plasma catecholamine and blood lactate accumulation during progressive exercise in the endurance-trained athletes.
Chwalbínska-Moneta
J
J
Department of Applied Physiology, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
Krysztofiak
F
F
Ziemba
A
A
Nazar
K
K
Kaciuba-Uściłko
H
H
D000328:Adult; D015308:Anaerobic Threshold; D002395:Catecholamines / Q000097:blood*; D015444:Exercise; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D009994:Osmolar Concentration; D010806:Physical Education and Training; D010807:Physical Endurance
D002395:Catecholamines; D019382:Human Growth Hormone; D019344:Lactic Acid