The effect of exercise type on immunofunctional and traditional growth hormone

Exerkines and long-term synaptic potentiation: Mechanisms of exercise-induced neuroplasticity

Physical exercise may improve cognitive function by modulating molecular and cellular mechanisms within the brain. We propose that the facilitation of long-term synaptic potentiation (LTP)-related pathways, by products induced by physical exercise (i.e., exerkines), is a crucial aspect of the exercise-effect on the brain. This review summarizes synaptic pathways that are activated by exerkines and may potentiate LTP. For a total of 16 exerkines, we indicated how blood and brain exerkine levels are altered depending on the type of physical exercise (i.e., cardiovascular or resistance exercise) and how they respond to a single bout (i.e., acute exercise) or multiple bouts of physical exercise (i.e., chronic exercise). This information may be used for designing individualized physical exercise programs. Finally, this review may serve to direct future research towards fundamental gaps in our current knowledge regarding the biophysical interactions between muscle activity and the brain at both cellular and system levels.

Acipimox Administration With Exercise Induces a Co-feedback Action of the GH, PP, and PYY on Ghrelin Associated With a Reduction of Peripheral Lipolysis in Bulimic and Healthy-Weight Czech Women: A Randomized Study

Objective: Anti-lipolytic drugs and exercise are enhancers of growth hormone (GH) secretion. Decreased circulating free fatty acids (FFA) have been proposed to exert ghrelin-GH feedback loop after administration of an anti-lipolytic longer-acting analog of nicotinic acid, Acipimox (OLB, 5-Methylpyrazine-2-carboxylic acid 4-oxide, molecular weight of 154.1 Da). OLB administration strongly suppresses plasma FFA during exercise. Neuroendocrine perturbations of the adipose tissue (AT), gut, and brain peptides may be involved in the etiopathogenesis of eating disorders including bulimia nervosa (BN) and anorexia nervosa. BN is characterized by binge eating, self-induced vomiting or excessive exercise. Approach: To test the hypothesis that treatment with OLB together with exercise vs. exercise alone would induce feedback action of GH, pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), and leptin on ghrelin in Czech women with BN and in healthy-weight Czech women (HW). The lipolysis rate (as glycerol release) in subcutaneous abdominal AT was assessed with microdialysis. At an academic medical center, 12 BN and 12 HW (the control group) were randomized to OLB 500 mg 1 h before a single exercise bout (45 min, 2 W/kg of lean body mass [LBM]) once a week vs. identical placebo over a total of 2 weeks. Blood plasma concentrations of GH, PP, PYY, leptin, ghrelin, FFA, glycerol, and concentrations of AT interstitial glycerol were estimated during the test by RIA utilizing ¹²⁵I-labeled tracer, the electrochemiluminescence technique (ECLIA) or colorimetric kits. Results: OLB administration together with short-term exercise significantly increased plasma GH (P < 0.0001), PP (P < 0.0001), PYY, and leptin concentrations and significantly decreased plasma ghrelin (P < 0.01) concentrations in both groups, whereas short-term exercise with placebo resulted in plasma ghrelin (P < 0.05) decrease exclusively in BN. OLB administration together with short-term exercise significantly lowered local subcutaneous abdominal AT interstitial glycerol (P < 0.0001) to a greater extent in BN. Conclusion: OLB-induced suppression of plasma ghrelin concentrations together with short-term exercise and after the post-exercise recovering phase suggests a potential negative co-feedback of GH, PP, PYY, and leptin on ghrelin secretion to a greater extent in BN. Simultaneously, the exercise-induced elevation in AT interstitial glycerol leading to a higher inhibition of peripheral lipolysis by OLB in BN. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03338387.

Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18-65 years old) who are overfat, or obese; systematic review and meta-analysis

There are number of means of methods to alter body composition, and metabolic issues, available for the adult who is overfat. The following is a systematic review and meta-analysis focused on comparing changes from treatment program for adults who are overfat based on analysis of aggregated effect size (ES) of inducing changes. So as to determine the relative effectiveness of such protocols and intervention plans of choice. This tiered meta-analysis of 66-population based studies, and 162-studywise groups, a clear pattern of ES being established across and within treatments. First, hypocaloric balance is necessary for changing body composition, but the effectiveness for establishing imbalance does not equate with the effectiveness for body compositional changes, or any biomarkers associated with metabolic issues. With analysis showing that there is a necessity to include exercise in combination with diet effectively elicit changes in body composition and biomarkers of metabolic issues. More importantly, the combination, resistance training (RT) was more effective than endurance training (ET) or combination of RT and ET, particularly when progressive training volume of 2-to-3 sets for 6-to-10 reps at an intensity of ≥75% 1RM, utilizing whole body and free-weight exercises, at altering body compositional measures (ES of 0.47, 0.30, and 0.40 for loss of BM, FM, and retention of FFM respectively) and reducing total cholesterol (ES = 0.85), triglycerides (ES = 0.86) and low-density lipoproteins (ES = 0.60). Additionally RT was more effective at reducing fasting insulin levels (ES = 3.5) than ET or ET and RT. Even though generally lower ES than RT, the inclusion of ET was more effective when performed at high intensity (e.g. ≥70% VO2max or HRmax for 30-minutes 3-4x's/wk), or in an interval training style than when utilizing the relatively common prescribed method of low-to-moderate (e.g., 50-70% VO2max or HRmax for at least equal time) steady state method, ES of 0.35, 0.39, and 0.13 for BM, FM, and FFM respectively. Thus indicating that focus of treatment should be on producing a large metabolic stress (as induced by RT or high levels of ET) rather than an energetic imbalance for adults who are overfat.

Strength and aerobic training in overweight females in Gdansk, Poland

We compared the effects of 16-week-training on rest metabolic rate, aerobic power, and body fat, and the post-exercise effects upon rest oxygen uptake and respiratory exchange ratio in overweight middle-aged females. Twenty nine overweight women (BMI 29.9 ± 1.2 kg*m^-2) participated in training (3 days a week). The subjects were divided onto groups of aerobic (AT) and strength (ST) training. The results showed that the total body mass decrease and VO₂ max increase did not differ in both groups. Decrease in waist circumference after 16 weeks was higher in the ST group. In the ST group fat-free mass increased during the first 8 weeks. Rest metabolic rate was increased significantly at 16th week compared to initial value in ST group only. Significant increase in post-exercise resting VO₂ and respiratory exchange ratio at 12 and 36 h was observed after the strength training session only. Increase in rest metabolic rate and post-exercise rest energy expenditure occurred after strength training but not after aerobic training despite the similar increase in aerobic power. The effect of 8-16 weeks of strength training on body mass decrease was higher in comparison to aerobic training.

Obesity, growth hormone and exercise

Growth hormone (GH) is regulated, suppressed and stimulated by numerous physiological stimuli. However, it is believed that obesity disrupts the physiological and pathological factors that regulate, suppress or stimulate GH release. Pulsatile GH has been potently stimulated in healthy subjects by both aerobic and resistance exercise of the right intensity and duration. GH modulates fuel metabolism, reduces total fat mass and abdominal fat mass, and could be a potent stimulus of lipolysis when administered to obese individuals exogenously. Only pulsatile GH has been shown to augment adipose tissue lipolysis and, therefore, increasing pulsatile GH response may be a therapeutic target. This review discusses the factors that cause secretion of GH, how obesity may alter GH secretion and how both aerobic and resistance exercise stimulates GH, as well as how exercise of a specific intensity may be used as a stimulus for GH release in individuals who are obese. Only five prior studies have investigated exercise as a stimulus of endogenous GH in individuals who are obese. Based on prior literature, resistance exercise may provide a therapeutic target for releasing endogenous GH in individuals who are obese if specific exercise programme variables are utilized. Biological activity of GH indicates that this may be an important precursor to beneficial changes in body fat and lean tissue mass in obese individuals. However, additional research is needed including what molecular GH variants are acutely released and involved at target tissues as a result of different exercise stimuli and what specific exercise programme variables may serve to stimulate GH in individuals who are obese.

Different responses of selected hormones to three types of exercise in young men

Exercise is a potent stimulus for release of growth hormone (GH), cortisol, testosterone and prolactin, and prolonged exercise inhibits insulin secretion. These responses seem to be specific to the type of exercise but this has been poorly characterised primarily because they have not been compared during exercise performed by the same individuals. We investigated hormone responses to resistance, sprint and endurance exercise in young men using a repeated measures design in which each subject served as their own control. Eight healthy non-obese young adults (18-25 years) were studied on four occasions in random order: 30-s cycle ergometer sprint (Sprint), 30-min resistance exercise bout (Resistance), 30-min cycle at 70 % VO(2max) (Endurance), and seated rest in the laboratory (Rest). Cortisol, GH, testosterone, prolactin, insulin and glucose concentrations were measured for 60 min after the four different interventions. Endurance and sprint exercise significantly increased GH, cortisol, prolactin and testosterone. Sprint exercise also increased insulin concentrations, whereas this decreased in response to endurance exercise. Resistance exercise significantly increased only testosterone and glucose. Sprint exercise elicited the largest response per unit of work, but the smallest response relative to mean work rate in all hormones. In conclusion, the nature and magnitude of the hormone response were influenced by exercise type, perhaps reflecting the roles of these hormones in regulating metabolism during and after resistance, sprint and endurance exercise.

A blend of chlorophytum borivilianum and velvet bean increases serum growth hormone in exercise-trained men

Background:

Several isolated ingredients have been proposed to increase growth hormone (GH) release, including Chlorophytum borivilianum and Velvet bean. A combination of these two ingredients has been packaged within an investigational dietary supplement. It was the purpose of the present investigation to determine the impact of acute ingestion of this supplement on circulating GH in healthy, exercise-trained men.

Methods:

Fifteen men ingested the dietary supplement on two different days, separated by one week. Blood was collected from subjects before ingestion of the supplement and at 20, 40, 60, 80, 100, and 120 minutes post ingestion. GH was analyzed in serum samples using an ELISA method. Values for GH for each subject, at each collection time, were averaged over both test days and used in the main analysis.

Results:

Serum GH increased over time, with higher values at 60 minutes (1.56 ± 0.65 ng · mL⁻¹; P = 0.04; +767%), 80 minutes (1.76 ± 0.69 ng · mL⁻¹; P = 0.02; +878%), and 100 minutes (1.48 ± 0.62 ng · mL⁻¹; P = 0.05; +722%) compared to pre ingestion (0.18 ± 0.04 ng · mL⁻¹). A great deal of subject variability existed in the area under the curve (AUC) for GH, with pooled values ranging from 0.49 to 61.2 ng · mL⁻¹ · 2 hr⁻¹

Conclusion:

Acute ingestion of an investigational dietary supplement containing the active ingredients Chlorophytum borivilianum and Velvet bean results in an increase in circulating GH in exercise-trained men. Additional placebo controlled investigations are needed to extend these findings. Moreover, studies are needed to determine if chronic use of such supplementation leads to favorable changes in health-related parameters associated with increased circulating GH.

Immunoreactive and bioactive growth hormone responses to resistance exercise in men who are lean or obese

It has been suggested that obese individuals have a blunted growth hormone (GH) response to spontaneous and stimulated GH secretion. The present study was designed to examine the effects of a high-volume, whole body acute resistance exercise (RE) protocol on immunoreactive GH (iGH), bioactive GH (bGH), and GH-binding protein (GHBP) in sedentary lean and obese men. Nine obese (mean ± SD: 20.8 ± 2.1 yr old, 177.0 ± 4.1 cm height, 108.7 ± 15.9 kg body mass, 37.6 ± 5.29% body fat) and nine lean (20.1 ± 2.1 yr old, 177.8 ± 8.7 cm height, 71.7 ± 5.8 kg body mass, 14.7 ± 3.54% body fat) men completed an acute RE protocol (6 exercises, 3 sets of 10 repetitions at 85–95% of 10 repetitions maximum with 120- and 90-s rest periods), and blood samples were collected before, at the midpoint, and immediately after exercise and during recovery (+50, +70, and +110). In contrast to prior studies, which examined acute responses to cardiovascular exercise protocols, groups did not differ in iGH response to the exercise stimulus. However, bGH concentrations overall were significantly lower in the obese than the lean participants ( P < 0.001). Additionally, obese individuals had significantly higher GHBP concentrations ( P < 0.001). Results suggest that obese and lean sedentary men performing a high-volume, whole body acute RE protocol demonstrate similar increases in iGH. Blunted bGH and elevated GHBP concentrations are indicative of altered GH activity associated with obesity. Prior research findings of blunted iGH response may be attributable to RE protocols not equated on relative intensity or volume. These results underscore the complexity of pituitary biology and its related mechanisms and may have implications for exercise prescription in the treatment of obesity.

Effect of resistance exercise, with or without carbohydrate supplementation, on plasma ghrelin concentrations and postexercise hunger and food intake

The effects of resistance exercise with and without carbohydrate (CHO) supplementation on hunger, postexercise food intake, and plasma ghrelin, an orexigenic gastric peptide, are poorly characterized. We examined the individual and combined effects of a resistance exercise bout and CHO consumption on plasma ghrelin and postexercise food intake. Twenty-one apparently healthy young male participants ([mean +/- SD] age = 20 +/- 1.8 years, body mass index = 24.8 +/- 3.3 kg/m(2)) completed in random order 3 treatment conditions: (1) ExCHO-80-minute resistance exercise bout while consuming CHO ( approximately 77 g CHO, 306 kcal); (2) ExPLA-identical exercise with a non=caloric placebo; and (3) NoExCHO-no-exercise trial of quiet sitting and CHO consumption. Blood samples were obtained before, during, and immediately postexercise, and 110 minutes after exercise. At 2 hours postexercise, they were provided a buffet of food from which they ate ad libitum. There was a significant time x treatment interaction for plasma ghrelin caused by a decline from pre- to postexercise in the 2 exercise conditions compared with an increase over time in the NoExCHO condition. At 110 minutes postexercise, ghrelin was 21% and 13% lower in ExCHO and ExPLA compared with NoExCHO (both Ps < .05). However, despite the lower ghrelin concentrations for the 2 exercise conditions, the subjective ratings of hunger were not lower for these conditions compared with the NoExCHO. There were no differences in absolute ad libitum energy intake from the buffet among the 3 conditions, but relative energy intake from the buffet accounting for the estimated cost of exercise was lowest among the 2 exercise conditions. We conclude that (1) weight lifting lowers plasma ghrelin concentrations during exercise and attenuates its rise during the postexercise period in young men and (2) the lower plasma ghrelin concentration is not associated with lower subjective feelings of hunger measured 100 minutes postexercise, but is associated with a lower relative food intake.

Growth hormone responses to 3 different exercise bouts in 18- to 25- and 40- to 50-year-old men

Exercise is a potent stimulus for growth hormone (GH) release, although aging appears to attenuate this response. The aim of this study was to investigate GH responses to different exercise stimuli in young and early middle-aged men. Eight men aged 18-25 y and 8 men aged 40-50 y completed 3 trials, at least 7 days apart, in a random order: 30 s cycle-ergometer sprint (sprint), 30 min resistance exercise bout (resistance), 30 min cycle at 70% maximal oxygen consumption (endurance). Blood samples were taken pre-, during, and post-exercise, and area under the GH vs. time curve was calculated for a total of 120 min. Mean blood lactate concentrations and percentage heart rate maximum at which the participants were working were not different between groups in any of the trials. In both groups, blood lactate concentrations were significantly lower in the endurance trial than in the sprint and resistance trials. There were no significant differences in resting GH concentration between groups or trials. GH AUC was significantly greater in the young group than the early middle-aged group, in both sprint (531 (+/-347) vs. 81 (+/-54) microg.L-1 per 120 min, p = 0.003) and endurance trials (842 (+/-616) vs. 177 (+/-137) microg.L-1 per 120 min, p = 0.010). Endurance exercise elicits a greater GH response than sprint and resistance exercise; however, aging per se, factors associated with aging, or an inability to achieve a sufficient absolute exercise intensity results in a smaller GH response to an exercise stimulus in early middle-aged men.