Oral L-Arginine Before Resistance Exercise Blunts Growth Hormone in Strength Trained Males

2014 ◽  
Vol 24 (2) ◽  
pp. 236-244 ◽  
Author(s):  
Scott C. Forbes ◽  
Vicki Harber ◽  
Gordon J. Bell
Keyword(s):  
Growth Hormone ◽  
Resistance Exercise ◽  
Body Mass ◽  
Area Under The Curve ◽  
Training Experience ◽  
Double Blind ◽  
Acute Bout ◽  
Plasma Gh ◽  
Arginine Concentration ◽  
And Training

Acute resistance exercise and L-arginine have both been shown to independently elevate plasma growth hormone (GH) concentrations; however, their combined effect is controversial. The purpose was to investigate the combined effects of resistance exercise and L-arginine supplementation on plasma L-arginine, GH, GH secretagogues, and IGF-1 in strength trained participants. Fourteen strength trained males (age: 25 ± 4 y; body mass: 81.4 ± 9.0 kg; height: 179.4 ± 6.9 cm; and training experience: 6.3 ± 3.4 y) participated in a randomized double-blind crossover design (separated by ~7 days). Subjects reported to the laboratory at 08:00 in a fasted state, consumed L-arginine (ARG; 0.075 g·kg−1 body mass) or a placebo (PLA) before performing an acute bout of resistance exercise (3 sets of 8 exercises, 10 repetitions at ~75% 1RM). Blood samples were collected at rest, before exercise, and at 0, 15, 30, and 60 min of rest-recovery. The ARG condition significantly increased plasma L-arginine concentrations (~120%) while no change was detected in the PLA condition. There were no differences between conditions for GH, GH-releasing hormone, ghrelin, or IGF-1 at any time point. GH-inhibiting hormone was significantly lower in the ARG condition. However, integrated area under the curve for GH was blunted in the ARG condition (L-arginine = 288.4 ± 368.7 vs. placebo = 487.9 ± 482.0 min·ng·mL−1, p < .05). L-arginine ingested before resistance exercise significantly elevated plasma L-arginine concentration but attenuated plasma GH in strength trained individuals despite a lower GHIH. Furthermore our data shows that the GH suppression was not due to a GH or IGF-1 induced autonegative feedback loop.

Carbohydrate Supplementation and Immune Responses after Acute Exhaustive Resistance Exercise

2008 ◽  
Vol 18 (3) ◽  
pp. 247-259 ◽  
Author(s):  
Lara A. Carlson ◽  
Samuel Headley ◽  
Jason DeBruin ◽  
Alex P. Tuckow ◽  
Alexander J. Koch ◽  
...  
Keyword(s):  
Immune Responses ◽  
Resistance Exercise ◽  
Serum Cortisol ◽  
Weight Lifting ◽  
Ice Hockey ◽  
Track And Field ◽  
Plasma Lactate ◽  
Double Blind ◽  
Acute Bout ◽  
Carbohydrate Supplementation

This investigation sought to study changes in leukocyte subsets after an acute bout of resistance exercise (ARE) and to determine whether ingestion of carbohydrate (CHO) could attenuate those immune responses. Nine male track-and-field athletes (21.1 ± 1.4 yr, 177.2 ± 5.5 cm, 80.9 ± 9.7 kg, 8.7% ± 3.8% fat) and 10 male ice hockey athletes (21.0 ± 2.2 yr, 174.3 ± 6.2 cm, 79.6 ±11.1 kg, 13.9% ± 3.73% fat) participated in 2 different ARE protocols. Both experiments employed a counterbalanced double-blind research design, wherein participants consumed either a CHO (1 g/kg body weight) or placebo beverage before, during, and after a weight-lifting session. Serum cortisol decreased (p < .05) at 90 min into recovery compared with immediately postexercise. Plasma lactate, total leukocyte, neutrophil, and monocyte concentrations increased (p < .05) from baseline to immediately postexercise. Lymphocytes decreased significantly (p < .05) from baseline to 90 min postexercise. Lymphocytes were lower (p < .05) for the CHO condition than for placebo. The findings of this study indicate the following: ARE appears to evoke changes in immune cells similar to those previously reported during endurance exercise, and CHO ingestion attenuates lymphocytosis after ARE.

Carbohydrate Supplementation Attenuates Muscle Glycogen Loss during Acute Bouts of Resistance Exercise

2000 ◽  
Vol 10 (3) ◽  
pp. 326-339 ◽  
Author(s):  
G. Gregory Haff ◽  
Alexander J. Koch ◽  
Jeffrey A. Potteiger ◽  
Karen E. Kuphal ◽  
Lawrence M. Magee ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Body Mass ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Placebo Treatment ◽  
Double Blind ◽  
Isokinetic Test ◽  
Before And After ◽  
Leg Exercise ◽  
Wet Weight

The effects of carbohydrate (CHO) supplementation on muscle glycogen and resistance exercise performance were examined with eight highly resistance trained males (mean ± SEM, age: 24.3 ± 1.1 years, height: 171.9±2.0 cm, body mass: 85.7 ± 3.5 kg; experience 9.9 ± 2.0 years). Subjects participated in a randomized, double blind protocol with testing sessions separated by 7 days. Testing consisted of an initial isokinetic leg exercise before and after an isotonic resistance exercise (IRT) session consisting of 3 leg exercises lasting ~39 min. Subjects consumed a CHO (1.0 g CHO ·kg body mass−1) or placebo treatment (PLC), prior to and every 10-min (0.5 g CHO ·kg body mass−1) during the IRT. Muscle tissue was obtained from the m vastus lateralis after a supine rest (REST) immediately after the initial isokinetic test (POST-ISO) and immediately after the IRT (POST-IRT). The CHO treatment elicited significantly less muscle glycogen degradation from the POST-ISO to POST-IRT (126.9 ± 6.5 to 109.7 ± 7.1 mmol·kg wet weight−1) compared to PLC (121.4±8.1 to 88.3±6.0 mmol·kg wet weight−1). There were no differences in isokinetic performance between the treatments. The results of this investigation indicate that the consumption of a CHO beverage can attenuate the decrease in muscle glycogen associated with isotonic resistance exercise but does not enhance the performance of isokinetic leg exercise.

scholarly journals Effects ofβ-Hydroxy-β-methylbutyrate Free Acid Ingestion and Resistance Exercise on the Acute Endocrine Response

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Jeremy R. Townsend ◽  
Jay R. Hoffman ◽  
Adam M. Gonzalez ◽  
Adam R. Jajtner ◽  
Carleigh H. Boone ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Repeated Measures ◽  
Free Acid ◽  
Area Under The Curve ◽  
High Volume ◽  
Endocrine Response ◽  
Exercise Protocol ◽  
Volume Resistance ◽  
Heavy Resistance Exercise ◽  
Plasma Gh

Objective. To examine the endocrine response to a bout of heavy resistance exercise following acuteβ-hydroxy-β-methylbutyrate free acid (HMB-FA) ingestion.Design. Twenty resistance trained men were randomized and consumed either 1 g of HMB-FA (BetaTor) or placebo (PL) 30 min prior to performing an acute heavy resistance exercise protocol. Blood was obtained before (PRE), immediately after (IP), and 30 min after exercise (30P). Circulating concentrations of testosterone, growth hormone (GH), insulin-like growth factor (IGF-1), and insulin were assayed. Data were analyzed with a repeated measures ANOVA and area under the curve (AUC) was analyzed by the trapezoidal rule.Results. The resistance exercise protocol resulted in significant elevations from PRE in testosteroneP<0.01, GHP<0.01, and insulinP=0.05at IP, with GHP<0.01and insulinP<0.01remaining elevated at 30P. A significant interaction was noted between groups in the plasma GH response at IP, which was significantly higher following HMB-FA compared to PLP<0.01. AUC analysis revealed an elevated GH and IGF-1 response in the HMB-FA group compared to PL.Conclusion. HMB-FA prior to resistance exercise augments the GH response to high volume resistance exercise compared to PL. These findings provide further support for the potential anabolic benefits associated with HMB supplementation.

Growth Hormone Response to an Acute Bout of Resistance Exercise in Weight-Trained and Non–Weight-Trained Women

2000 ◽  
Vol 14 (2) ◽  
pp. 220 ◽  
Author(s):  
JANE M. TAYLOR ◽  
HEATHER S. THOMPSON ◽  
PRISCILLA M. CLARKSON ◽  
MARY P. MILES ◽  
MARY JANE DE SOUZA
Keyword(s):  
Growth Hormone ◽  
Resistance Exercise ◽  
Growth Hormone Response ◽  
Hormone Response ◽  
Acute Bout

scholarly journals Differential pulsatile secretagogue control of GH secretion in healthy men

2013 ◽  
Vol 304 (9) ◽  
pp. R712-R719 ◽  
Author(s):  
Catalina Norman ◽  
John Miles ◽  
Cyril Y. Bowers ◽  
Johannes D. Veldhuis
Keyword(s):  
Body Mass Index ◽  
Growth Hormone ◽  
Regression Analysis ◽  
Body Mass ◽  
Older Men ◽  
Regulatory Mechanisms ◽  
Double Blind ◽  
Healthy Men ◽  
Gh Secretion ◽  
Integrated Regulation

Pulsatile growth hormone (GH) secretion putatively reflects integrated regulation by GH-releasing hormone (GHRH), somatostatin (SST), and GH-releasing peptide (GHRP). GHRH and SST secretion is itself pulsatile. However, how GHRH and SST pulses act along with GHRP to jointly determine pulsatile GH secretion is unclear. Moreover, how testosterone (T) modulates such interactions is unknown. These queries were assessed in a prospectively randomized, placebo-controlled double-blind cohort comprising 26 healthy older men randomized to testosterone (T) vs. placebo supplementation. Pulses of GHRH, SST, or saline were infused intravenously at 90-min intervals for 13 h, along with either continuous saline or ghrelin analog (GHRP-2). The train of pulses was followed by a triple stimulus (combined l-arginine, GHRH, and GHRP-2) to estimate near-maximal GH secretion over a final 3 h. Testosterone vs. placebo supplementation doubled pulsatile GH secretion during GHRH pulses combined with continuous saline (GHRH/saline) ( P < 0.01). Pulsatile GH secretion correlated positively with T concentrations (270–1,170 ng/dl) in the 26 men during saline pulses/saline ( P = 0.015, R2 = 0.24), GHRH pulses/saline ( P = 0.020, R2 = 0.22), and combined GHRH pulses/GHRP-2 ( P = 0.016, R2 = 0.25) infusions. Basal nonpulsatile GH secretion correlated with T during saline pulses/GHRP-2 drive ( P = 0.020, R2 = 0.16). By regression analysis, pulsatile GH secretion varied negatively with body mass index (BMI) during saline/GHRP-2 infusion ( P = 0.001, R2 = 0.36), as well as after the triple stimulus preceded by GHRH/GHRP-2 ( P = 0.013, R2 = 0.23). Mean (10-h) GH concentrations under GHRP-2 were predicted jointly by estradiol (positively) and BMI (negatively) ( P < 0.001, R2 = 0.520). These data indicate that estradiol, T, and BMI control pulsatile secretagogue-specific GH-regulatory mechanisms in older men.

scholarly journals Oral arginine attenuates the growth hormone response to resistance exercise

2006 ◽  
Vol 101 (3) ◽  
pp. 848-852 ◽  
Author(s):  
S. R. Collier ◽  
E. Collins ◽  
J. A. Kanaley
Keyword(s):  
Growth Hormone ◽  
Resistance Exercise ◽  
Area Under The Curve ◽  
Combined Effect ◽  
Hormone Response ◽  
Healthy Male ◽  
Repetition Maximum ◽  
Spontaneous Growth ◽  
The Subject ◽  
Male Subjects

This study investigated the combined effect of resistance exercise and arginine ingestion on spontaneous growth hormone (GH) release. Eight healthy male subjects were studied randomly on four separate occasions [placebo, arginine (Arg), placebo + exercise (Ex), arginine + exercise (Arg+Ex)]. Subjects had blood sampled every 10 min for 3.5 h. After baseline sampling (30 min), subjects ingested a 7-g dose of arginine or placebo (blinded, randomly assigned). On the exercise days, the subject performed 3 sets of 9 exercises, 10 repetitions at 80% one repetition maximum. Resting GH concentrations were similar on each study day. Integrated GH area under the curve was significantly higher on the Ex day (508.7 ± 169.6 min·ng/ml; P < 0.05) than on any of the other study days. Arg+Ex (260.5 ± 76.8 min·ng/ml) resulted in a greater response than the placebo day but not significantly greater than the Arg day. The GH half-life and half duration were not influenced by the stimulus administered. The GH secretory burst mass was larger, but not significantly, on the Arg, Ex, and Arg+Ex day than the placebo day. Endogenous GH production rate (Ex > Arg+Ex > Arg > placebo) was greater on the Ex and Arg+Ex day than on the placebo day ( P < 0.05) but there were no differences between the Ex and Arg+Ex day. Oral arginine alone (7 g) stimulated GH release, but a greater GH response was seen with exercise alone. The combined effect of arginine before exercise attenuates the GH response. Autonegative feedback possibly causes a refractory period such that when the two stimuli are presented there will be suppression of the somatotrope.

scholarly journals Appetite sensations and substrate metabolism at rest, during exercise, and recovery: impact of a high-calcium meal

2013 ◽  
Vol 38 (12) ◽  
pp. 1260-1267 ◽  
Author(s):  
Javier T. Gonzalez ◽  
Penny L.S. Rumbold ◽  
Emma J. Stevenson
Keyword(s):  
Confidence Interval ◽  
Body Mass ◽  
Area Under The Curve ◽  
Calcium Content ◽  
Peak Oxygen Uptake ◽  
Whole Body ◽  
Double Blind ◽  
Substrate Metabolism ◽  
High Carbohydrate ◽  
High Calcium

The aim of this study was to investigate the effects of the calcium content of a high-carbohydrate, pre-exercise meal on substrate metabolism and appetite sensations before, during, and after exercise. Nine active males participated in 2 trials in a double-blind, randomised, crossover design. After consuming a high carbohydrate (1.5 g·kg−1 of body mass) breakfast with a calcium content of either 3 (control trial) or 9 mg·kg−1 of body mass (high milk-calcium (CAL)), participants ran at 60% peak oxygen uptake for 60 min. Following exercise, a recovery drink was consumed and responses were investigated for a further 90 min. Blood and expired gas were sampled throughout to determine circulating substrate and hormone concentrations and rates of substrate oxidation. Visual analogue scales were also administered to determine subjective appetite sensations. Neither whole-body lipid oxidation nor non-esterified fatty acid availability differed between trials. The area under the curve for the first hour following breakfast consumption was 16% (95% confidence interval: 0%–35%) greater for fullness and 10% (95% confidence interval: 2%–19%) greater for insulin in the CAL trial but these differences were transient and not apparent later in the trial. This study demonstrates that increasing the calcium content of a high carbohydrate meal transiently increases insulinemia and fullness but substrate metabolism is unaffected.

scholarly journals Mechanical Analysis of the Acute Effects of a Heavy Resistance Exercise Warm-Up on Agility Performance in Court-Sport Athletes

2013 ◽  
Vol 39 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Christopher J. Sole ◽  
Gavin L. Moir ◽  
Shala E. Davis ◽  
Chad A. Witmer
Keyword(s):  
Resistance Exercise ◽  
Body Mass ◽  
Reaction Force ◽  
Body Height ◽  
Stride Frequency ◽  
Camera Motion ◽  
Acute Effects ◽  
Training Experience ◽  
Warm Up ◽  
Heavy Resistance Exercise

Abstract The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.

Sign in / Sign up

Export Citation Format

Share Document