LakeMountD
Doctor Science
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LH secretion and testosterone concentrations are blunted after resistance exercise in men
I will post various quotes from this study since it is so big and the abstract sucks. The data suggests that it would be best to take a cortisol reducer during exercise to prevent your body from breaking down muscle glycogen and other nutrients for use as fuel (just eat a low GI meal before hand) and also to take one before bed to combat the nighttime spike seen in the first and later hours of sleep. ZMA and possibly trib and fenugreek are also great choices to keep test levels up at night.
"This study has shown that high-volume, whole body heavy-resistance exercise in the late afternoon resulted in lowered concentrations of TT and FT throughout the night in young, healthy men. These lowered testosterone concentrations were accompanied by a lowered LH production rate and elevated C concentrations. Thus these data support an inhibited hypothalamic-pituitary regulation of LH secretion as a possible mechanism mediating lower androgen concentrations after strenuous resistance exercise. These findings also show that a single bout of resistance exercise can have an impact on endocrine function that is sustained for >= 13 h after exercise. This study is unique, in that we have employed a rigorous blood sampling scheme (every 10 min overnight from 1700 to 0600 for LH and every hour for TT, FT, and C for 13 h after exercise) to more fully characterize the effect of resistance exercise on the pituitary-adrenal-testicular endocrine axis. Additionally, this report represents the only available study to use deconvolution analysis to assess pulsatile LH secretion after resistance exercise in men. This is an important distinction, inasmuch as the abundance of the previous exercise/LH literature has focused on women (17, 18, 33) or endurance exercise in men (8, 11, 19, 20, 23)."
"Of interest is the mechanism whereby overnight testosterone concentrations appeared lower in the circulation after heavy-resistance exercise. In a recent study, De Leo et al. (4) injected saline or 5,000 IU of human chorionic gonadotropin (hCG, a stimulator of Leydig cell testosterone secretion) into a group of 18 men and showed that the reduction in testosterone concentrations after exercise did not occur when hCG was administered. Prior studies using hCG or gonadotropin-releasing hormone injection have also shown that the testes retain their ability to secrete testosterone in the face of prolonged physical or operational stress (27). The available data seem to point away from a gonadal defect to explain lowered testosterone concentrations and toward a centrally mediated mechanism that is hypothalamic-pituitary in origin."
"We previously reported that acute resistance protocols lasting <= 1 h result in elevations in testosterone and that these elevations are influenced by the relative intensity and rest periods between sets (15, 16). We have hypothesized that these testosterone increases facilitate tissue repair and recovery processes after the mircotrauma of repetitive near-maximal muscular contractions (i.e., a greater testosterone increase, a greater biological impact). At face value, this seems reasonable, inasmuch as testosterone is known to promote protein synthesis and glycogen metabolism. However, in light of this study's observation that testosterone concentrations were lower after a resistance exercise bout configured with acute program variables known to increase muscle hypertrophy and strength when performed on a chronic basis (e.g., exercises, relative loads, sets, rest between sets), how should the lowered testosterone concentrations after the resistance exercise in this study be interpreted? Urhausen et al. (26) suggested that the physiological implications of lowered testosterone concentrations after physical exercise could result in an impaired resynthesis of protein and glycogen during the regeneration phase. This, in turn, would induce a shift in the energy metabolism toward an increased fat and decreased carbohydrate utilization. Hence, the lowered testosterone concentrations, in conjunction with elevated C concentrations, likely modulate enhanced lipolytic activity and protein catabolism. Immediately after the stress imposed by high-volume muscular contractions, the body is in a catabolic, rather than an anabolic, energy flux. Hence, a provision of fuels mitigated by lowered testosterone and elevated C assists to replenish energy stores and supply the precursors for later use in gluconeogenesis and protein synthesis."
"C responses. Overall C concentrations were significantly elevated in the exercise condition. Close scrutiny of the C response patterns, however, indicated that the difference under the conditions was mainly attributed to the large C rise for the 2-3 h immediately after exercise. As mentioned above, the rise in C, along with other metabolic regulators (e.g., catecholamines and growth hormone), contributes to fuel provision to meet the metabolic demands of exercise. Our results differ from the only other study to evaluate overnight C responses after daytime resistance exercise and also from one report on endurance exercise. McMurray et al. (21) reported that resistance exercise conducted at 1800 and comprised of 18 sets did not alter overnight C concentrations compared with the control condition, whereas Hackney (8) reported decreased overnight C concentrations after 90 min of cycling at 70% VO2 max. Consistent with our results, Kern et al. (13) reported that low and moderate daytime cycling endurance exercise induced higher C concentrations during the first half of sleep."
Link to full article
http://jap.physiology.org/cgi/content/full/91/3/1251
The dotted lines on graph represent exercised group and solid lines represent control group who did not exercise. 1-13 is showing the hours of sleep and the hormonal responses. Notice test levels are lower in the exercised group at night and that cortisol levels are much higher.
I will post various quotes from this study since it is so big and the abstract sucks. The data suggests that it would be best to take a cortisol reducer during exercise to prevent your body from breaking down muscle glycogen and other nutrients for use as fuel (just eat a low GI meal before hand) and also to take one before bed to combat the nighttime spike seen in the first and later hours of sleep. ZMA and possibly trib and fenugreek are also great choices to keep test levels up at night.
"This study has shown that high-volume, whole body heavy-resistance exercise in the late afternoon resulted in lowered concentrations of TT and FT throughout the night in young, healthy men. These lowered testosterone concentrations were accompanied by a lowered LH production rate and elevated C concentrations. Thus these data support an inhibited hypothalamic-pituitary regulation of LH secretion as a possible mechanism mediating lower androgen concentrations after strenuous resistance exercise. These findings also show that a single bout of resistance exercise can have an impact on endocrine function that is sustained for >= 13 h after exercise. This study is unique, in that we have employed a rigorous blood sampling scheme (every 10 min overnight from 1700 to 0600 for LH and every hour for TT, FT, and C for 13 h after exercise) to more fully characterize the effect of resistance exercise on the pituitary-adrenal-testicular endocrine axis. Additionally, this report represents the only available study to use deconvolution analysis to assess pulsatile LH secretion after resistance exercise in men. This is an important distinction, inasmuch as the abundance of the previous exercise/LH literature has focused on women (17, 18, 33) or endurance exercise in men (8, 11, 19, 20, 23)."
"Of interest is the mechanism whereby overnight testosterone concentrations appeared lower in the circulation after heavy-resistance exercise. In a recent study, De Leo et al. (4) injected saline or 5,000 IU of human chorionic gonadotropin (hCG, a stimulator of Leydig cell testosterone secretion) into a group of 18 men and showed that the reduction in testosterone concentrations after exercise did not occur when hCG was administered. Prior studies using hCG or gonadotropin-releasing hormone injection have also shown that the testes retain their ability to secrete testosterone in the face of prolonged physical or operational stress (27). The available data seem to point away from a gonadal defect to explain lowered testosterone concentrations and toward a centrally mediated mechanism that is hypothalamic-pituitary in origin."
"We previously reported that acute resistance protocols lasting <= 1 h result in elevations in testosterone and that these elevations are influenced by the relative intensity and rest periods between sets (15, 16). We have hypothesized that these testosterone increases facilitate tissue repair and recovery processes after the mircotrauma of repetitive near-maximal muscular contractions (i.e., a greater testosterone increase, a greater biological impact). At face value, this seems reasonable, inasmuch as testosterone is known to promote protein synthesis and glycogen metabolism. However, in light of this study's observation that testosterone concentrations were lower after a resistance exercise bout configured with acute program variables known to increase muscle hypertrophy and strength when performed on a chronic basis (e.g., exercises, relative loads, sets, rest between sets), how should the lowered testosterone concentrations after the resistance exercise in this study be interpreted? Urhausen et al. (26) suggested that the physiological implications of lowered testosterone concentrations after physical exercise could result in an impaired resynthesis of protein and glycogen during the regeneration phase. This, in turn, would induce a shift in the energy metabolism toward an increased fat and decreased carbohydrate utilization. Hence, the lowered testosterone concentrations, in conjunction with elevated C concentrations, likely modulate enhanced lipolytic activity and protein catabolism. Immediately after the stress imposed by high-volume muscular contractions, the body is in a catabolic, rather than an anabolic, energy flux. Hence, a provision of fuels mitigated by lowered testosterone and elevated C assists to replenish energy stores and supply the precursors for later use in gluconeogenesis and protein synthesis."
"C responses. Overall C concentrations were significantly elevated in the exercise condition. Close scrutiny of the C response patterns, however, indicated that the difference under the conditions was mainly attributed to the large C rise for the 2-3 h immediately after exercise. As mentioned above, the rise in C, along with other metabolic regulators (e.g., catecholamines and growth hormone), contributes to fuel provision to meet the metabolic demands of exercise. Our results differ from the only other study to evaluate overnight C responses after daytime resistance exercise and also from one report on endurance exercise. McMurray et al. (21) reported that resistance exercise conducted at 1800 and comprised of 18 sets did not alter overnight C concentrations compared with the control condition, whereas Hackney (8) reported decreased overnight C concentrations after 90 min of cycling at 70% VO2 max. Consistent with our results, Kern et al. (13) reported that low and moderate daytime cycling endurance exercise induced higher C concentrations during the first half of sleep."
Link to full article
http://jap.physiology.org/cgi/content/full/91/3/1251
The dotted lines on graph represent exercised group and solid lines represent control group who did not exercise. 1-13 is showing the hours of sleep and the hormonal responses. Notice test levels are lower in the exercised group at night and that cortisol levels are much higher.
