Effects of heavy-resistance training on hormonal response patterns in younger vs. older men

Abstract

To examine the adaptations of the endocrine system to heavy-resistance training in younger vs. older men, two groups of men (30 and 62 yr old) participated in a 10-wk periodized strength-power training program. Blood was obtained before, immediately after, and 5, 15, and 30 min after exercise at rest before and after training and at rest at -3, 0, 6, and 10 wk for analysis of total testosterone, free testosterone, cortisol, growth hormone, lactate, and ACTH analysis. Resting values for insulin-like growth factor (IGF)-I and IGF-binding protein-3 were determined before and after training. A heavy-resistance exercise test was used to evaluate the exercise-induced responses (4 sets of 10-repetition maximum squats with 90 s of rest between sets). Squat strength and thigh muscle cross-sectional area increased for both groups. The younger group demonstrated higher total and free testosterone and IGF-I than the older men, training-induced increases in free testosterone at rest and with exercise, and increases in resting IGF-binding protein-3. With training the older group demonstrated a significant increase in total testosterone in response to exercise stress along with significant decreases in resting cortisol. These data indicate that older men do respond with an enhanced hormonal profile in the early phase of a resistance training program, but the response is different from that of younger men.

Influence of exercise intensity in older persons with unchanged habitual nutritional intake: skeletal muscle and endocrine adaptations

“…Most IGF-I (∼80%) circulates in a 150-kDa, high-affinity complex, which also contains IGFBP-3 and an acid-labile subunit. Analogous to the present findings, studies have found no change in IGF-I and IGFBP-3 concentrations following 8 (Bermon et al 1999) and 12 weeks (Kraemer et al 1999) of resistance training in a similarly aged population. In contrast, a significant increase in plasma IGF-I concentrations following an acute exercise bout was reported in one of these studies (Bermon et al 1999).…”

“…Then again, a lack of change in serum IGF-I with training may suggest that IGF-I in the circulation may not be a meaningful marker of the activity of the GH-IGF-I system. Alternatively, increased IGF-I secretion from the liver may be quickly sequestered by the tissue in order to maintain a homeostatic balance of IGF-I in the systemic circulation (Kraemer et al 1999), which may explain why we observed little change in these endocrine measures with either intervention but pronounced gains in muscle strength. Finally, it is also possible that the issue of timing of the sera sampling might have played a role in our observations and that hormonal adaptations may have occurred in a more acute fashion, which we would have missed (Kraemer and Ratamess 2005).…”

Do whole-body vibration exercise and resistance exercise modify concentrations of salivary cortisol and immunoglobulin A?

“…The cortisol responses observed in the present study were not consistent with previous reports that have shown acute increases in serum cortisol (17,18) or Scortisol (19,20) concentrations after a single bout of a hypertrophy-oriented exercise. Crewther et al (19) suggested that the increase in cortisol concentration is related to the total volume of RE (i.e., number of sets x external load).…”

“…Mulligan et al (17) corroborated these findings when they observed greater increases in cortisol after multiple sets rather than a single set of hypertrophy-oriented RE. In fact, acute increases in cortisol have been demonstrated after RE routines involving multiple exercises and/or involving a large muscle mass (9,(17)(18)(19)21).…”

Arquitetura muscular e envelhecimento: adaptação funcional e aspectos clínicos; revisão da literatura

“…Quando indivíduos idosos são submetidos a um programa de treinamento de força, os efeitos deletérios do envelhecimento são contrabalançados, sugerindo que grande parte dos mecanismos relacionados à sarcopenia são decorrentes do sedentarismo [22][23][24][25][26] . O objetivo deste artigo foi revisar a literatura corrente sobre os aspectos relacionados à arquitetura muscular e o envelhecimento, bem como apresentar os resultados de programas de treinamento de força nas propriedades morfológicas da musculatura esquelética, indicando perspectivas clínicas na adaptação funcional dessa população.…”