Hormonal, metabolic, and cardiorespiratory responses of young and adult athletes to a single session of high-intensity cycle exercise

• Published in: Pediatric exercise science Vol. 26; no. 4; p. 485
• Main Authors: Engel, Florian, Härtel, Sascha, Wagner, Matthias Oliver, Strahler, Jana, Bös, Klaus, Sperlich, Billy
• Format: Journal Article
• Language: English
• Published: United States 01-11-2014
• Subjects: Adult; Athletic Performance - physiology; Bicycling - physiology; Child; Exercise Test; Heart Rate - physiology; Humans; Hydrocortisone - analysis; Lactic Acid - blood; Male; Oxygen Consumption - physiology; Physical Exertion - physiology; Saliva - chemistry
• ISSN: 1543-2920
• DOI: 10.1123/pes.2013-0152

This study aimed to determine the effects of a single high-intensity interval training (HIIT) session on salivary cortisol (SC) levels, physiological responses, and performance in trained boys and men. Twenty-three boys (11.5 ± 0.8 years) and 25 men (29.7 ± 4.6 years) performed HIIT (4 consecutive Wingate Anaerobic Tests). SC in boys and men increased after HIIT from 5.55 ± 3.3 nmol/l to 15.13 ± 9.7 nmol/l (+173%) and from 7.07 ± 4.7 nmol/l to 19.19 ± 12.7 nmol/l (+171%), respectively (p < .01). Pretest SC as well as posttest changes were comparable in both groups (both p < .01). Peak blood lactate concentration was significantly lower in boys (12.6 ± 3.5 mmol/l) than in men (16.3 ± 3.1 mmol/l; p < .01). Throughout the HIIT, mean heart rates in boys were higher (p < .001) but relative peak oxygen uptake (ml·min-1·kg-1; p < .05) and performance were lower (p < .001) in boys than in men. HIIT in young athletes is associated with a higher activation of the hormonal stress axis than other types of exercise regimes as described in the literature. This study is the first to show a pronounced SC increase to HIIT in trained boys accompanied by elevated levels of blood lactate concentrations and heart rate suggesting a high cardio-respiratory, metabolic, and hormonal response to HIIT in 11-year-old boys.