With weightlifting exercise, the attenuation of the cortisol response is a major factor by which an increase in muscle mass occurs. A reduction in the exercise-induced cortisol response has been observed in younger but not older men, suggesting that under normal circumstances older men may lack the mechanism(s) to down-regulate cortisol activity. The purpose of this study was to determine if CHO consumption during a weightlifting exercise bout could modify the cortisol response to exercise. Five resistance-trained older men (62.8 ± 1.5 y) completed (on 2 occasions) a 9-station weightlifting protocol (3 sets, 10 repetitions, 75% of 1RM). One session included the ingestion of a placebo beverage, and the other, a CHO solution. Blood samples were collected prior to, during, and after the exercise bout. With the placebo, plasma glucose levels remained unchanged, while plasma cortisol levels were significantly elevated (from 284 ± 49.7 nmol/L to 474 ± 130 nmol/L). In contrast, CHO consumption resulted in significantly higher plasma glucose levels (from 5.55 ± .48 to 7.63 ± 0.53 mmol) and a blunted cortisol response. These findings indi-cate that the stimulatory effect of exercise on cortisol secretion can be overcome by CHO administration.
Tarpenning, K., Hawkins, S., & Wiswell, R. (2003). CHO-induced blunting of cortisol response to weightlifting exercise in resistance-trained older men. European Journal of Sport Science, 3(2), 1-11. https://doi.org/10.1080/17461390300073204