Studies have shown that endurance-trained men tend to have lower levels of testosterone compared to their sedentary counterparts and that resistance-trained men have higher basal testosterone levels. Studies have also found that both endurance- and resistance-trained males had lower testosterone levels than sedentary control subjects. Thus, while it is known that training status can influence the hormone response to exercise, it is not clear whether the mode of training can affect the hormone response to different modes of exercise. Such information could be useful in designing training regimes that will result in the most favorable ratio of anabolic and catabolic hormones.
A first-of-its-kind study attempts to determine the acute steroid hormone response to endurance and resistance exercise bouts of equitable volume in subjects with differing training status. The newly released findings conclude that the circulating endogenous hormone profile is more dependent on exercise mode or intensity than on exercise volume as measured by caloric expenditure. The study also provides evidence that hormone levels and exercise-induced hormone changes are different in subjects of different training status.
A New Study
The authors of the study, entitled, "Effect of Training Status and Exercise Mode on Endogenous Steroid Hormones in Males," are Mark S. Tremblay, Jennifer L. Copeland, and Walter Van Helder, all of the College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada. Their findings appear in the "Articles in Press" section of the Journal of Applied Physiology. The Journal of Applied Physiology is one of 14 scientific journals published each month by the American Physiological Society (APS).
Summary of Methodology
Twenty-two healthy males were recruited who were resistance-trained (RES, N=7), endurance-trained (END, N=8) or sedentary (SED, N=7). Each screened volunteer participated in four late afternoon sessions. This time was chosen because it best represented the typical time period during which the subjects trained and because variation of testosterone is minimized during this period.
During session one, baseline anthropometric and fitness measurements were obtained. During session two subjects rested quietly. A resting blood sample was drawn at 0.5 hours and subsequent blood samples were drawn each hour for the subsequent four hours. Plasma was analyzed for luteinizing hormone (LH), dehydroepiandrosterone sulfate (DHEAS), cortisol, and free and total testosterone. Endurance and resistance exercise bouts were completed during sessions three and four. These exercise sessions were matched according to caloric expenditure (calculated from expired gases). Each testing session was separated by at least one week.
Height, body mass, and skinfold thickness were taken, and strength measurements were performed. Maximal aerobic power was determined using a progressive, incremental treadmill protocol. Minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were monitored.
All data were presented as means ± standard deviation, and statistical significance was set at p<0.05. Total testosterone/cortisol, free testosterone/cortisol and DHEAS/cortisol ratios were calculated and compared in the same manner as individual hormones.
Results
Highlights of the findings include:
Conclusions
Sedentary, resistance-trained, and endurance-trained subjects were used in this study to identify differences in testosterone, LH, DHEAS, and cortisol, as well as the ratios of testosterone and DHEAS to cortisol. Based on the results of this study, it appears that the circulating endogenous hormone profile is more dependent on exercise mode or intensity than on exercise volume as measured by caloric expenditure. The relatively catabolic environment observed during the resistance session may indicate an intensity-dependent rather than mode-dependent response. The study also provides evidence that hormone levels and exercise-induced hormone changes are different in subjects of different training status.
Source : Journal of Applied Physiology, "Articles in Press" section. The Journal is one of 14 scientific journals published each month by the American Physiological Society (APS).
The American Physiological Society (APS) was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals every year.
Journal of Applied Physiology