The exercise-induced growth hormone response in athletes

Aspects of Elite Female Football Players' Training Loads and Sleep Variations

The current study investigated the associations between female football players' training loads and their sleep variations. The sample included 21 female elite football players from a Norwegian top-league club with a mean age of 24 years (±2.8). Sleep duration, sleep quality, and training load were monitored every day over 273 consecutive days with a Somnofy sleep monitor based on ultra-wideband (IR-UWB) pulse radar and Doppler technology, and a FIFA-approved STATSports APEX 10 Hz GPS tracking system monitoring players' training loads. A multivariate analysis of variance (MANOVA) was conducted to investigate the relationships between the players' training loads and sleep. It was revealed that very high training loads were associated with reduced time in bed (p = 0.005), total sleep time (p = 0.044)), and rapid eye movement (p < 0.001). The present findings show that the female football players' sleep was disrupted when the training load, based on total distance (TDI), was very high. It appears to be a point where their sleep is somewhat consistent through low, medium, and high training loads, but with disrupted sleep when the training load reaches a very high level. Considering the reduced TIB after a very high training load, there should be suggested strategies to improve their sleep, such as extended TIB, to aid in longer TST and improved recovery.

Effect of ADORA2A Gene Polymorphism and Acute Caffeine Supplementation on Hormonal Response to Resistance Exercise: A Double-Blind, Crossover, Placebo-Controlled Study

Previous studies have reported that TT genotype carriers of the adenosine A2a receptor (ADORA2A) gene rs5751876 polymorphism have better ergogenic and anti-inflammatory responses to caffeine intake compared to C allele carriers. The aim of the present study was twofold: (1) to investigate the association of the ADORA2A rs5751876 polymorphism with acute caffeine supplementation on hormonal (growth hormone and testosterone) response to resistance exercise (RE); (2) to examine the relationship between the rs5751876 polymorphism and the resting levels of growth hormone and testosterone in athletes who are light caffeine consumers. A double-blind, crossover, placebo-controlled study involving 30 resistance-trained men (age 21.7 ± 4.1) was conducted to assess the impact of caffeine supplementation on serum growth hormone (GH) and testosterone (TS) levels before, immediately after, and 15 min post-RE. One hour before engaging in resistance exercise, subjects were randomly administered 6 mg of caffeine per kg of body mass or a placebo (maltodextrin). After a 7-day washout period, the same protocol was repeated. Resting testosterone and growth hormone levels were examined in the sera of 94 elite athletes (31 females, age 21.4 ± 2.8; 63 males, age 22.9 ± 3.8). Caffeine consumption led to significantly greater increases in GH and TS in men with the TT genotype compared to C allele carriers. Furthermore, in the group of athletes, carriers of the TT genotype had significantly higher testosterone (p = 0.0125) and growth hormone (p = 0.0365) levels compared to C allele carriers. In conclusion, the ADORA2A gene rs5751876 polymorphism may modify the effect of caffeine intake on the hormonal response to exercise.

The impact of exercise on gene regulation in association with complex trait genetics

Endurance exercise training is known to reduce risk for a range of complex diseases. However, the molecular basis of this effect has been challenging to study and largely restricted to analyses of either few or easily biopsied tissues. Extensive transcriptome data collected across 15 tissues during exercise training in rats as part of the Molecular Transducers of Physical Activity Consortium has provided a unique opportunity to clarify how exercise can affect tissue-specific gene expression and further suggest how exercise adaptation may impact complex disease-associated genes. To build this map, we integrate this multi-tissue atlas of gene expression changes with gene-disease targets, genetic regulation of expression, and trait relationship data in humans. Consensus from multiple approaches prioritizes specific tissues and genes where endurance exercise impacts disease-relevant gene expression. Specifically, we identify a total of 5523 trait-tissue-gene triplets to serve as a valuable starting point for future investigations [Exercise; Transcription; Human Phenotypic Variation].

Supplementation with Lactiplantibacillus brevis GKEX Combined with Resistance Exercise Training Improves Muscle Mass, Strength Performance, and Body Fat Condition in Healthy Humans

In addition to maintaining good exercise and dietary habits, recent studies have shown that probiotics may have potential benefits for muscle mass and strength. It is worth noting that the effects may vary depending on the specific strains used. To date, no studies have analyzed the effects of Lactiplantibacillus brevis in this context. Here, we combine the L. brevis strain GKEX with resistance training to further understand its effects on muscle mass, thickness, performance, and fat loss. In a six-week intervention for a double-blind randomized trial, 52 healthy subjects were divided into two groups (10 male and 16 female participants in each group): a placebo group (two capsules/day, containing 0 CFU of GKEX per capsule) and a GKEX group (two capsules/day, containing 1 × 1010 CFU of GKEX per capsule). Before the intervention, no differences were observed between the two groups in any of the tests (body composition, muscle thickness, exercise performance, and blood parameters). However, supplementation with GKEX significantly improved muscle mass and thickness, as well as grip strength, muscle strength, and explosive performance, when compared to the associated parameters before the intervention. Additionally, GKEX supplementation promoted a reduction in the body fat percentage (p < 0.05). Through analysis of the change amount, we observed that GKEX supplementation yielded significantly improved benefits when compared to the placebo group (p < 0.05). In summary, our findings support the notion that a six-week resistance exercise training program combined with L. brevis GKEX supplementation has superior additive effects that enhance muscle mass and strength performance, while also reducing body fat percentage. This intervention can promote muscle gain and fat loss.

Update on Current Concepts of Blood Flow Restriction in the Perioperative Period of Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament tears or ruptures are common orthopedic injuries. Anterior cruciate ligament reconstruction (ACLR) is an orthopedic procedure allowing for earlier return to sports, improved maintenance of lifestyle demands, and restored knee stability and kinematics. A perioperative rehabilitative adjunct recently gaining interest is blood flow restriction (BFR), a method in which temporary restriction of blood flow to a chosen extremity is introduced and can be used as early as a few days postoperative. There has been increasing investigation and recent literature regarding BFR. This review synthesizes current concepts of BFR use in the ACLR perioperative period. [Orthopedics. 2023;46(6):e333-e340.].

Effect of exercise on the hypothalamic-pituitary-gonadal axis in a rat model of Alzheimer's disease

Hypothalamic-pituitary-gonadal (HPG) axis dysregulation was suggested to play a crucial role in Alzheimer's disease (AD). This study investigated the effects of exercise on HPG hormones in an AD rat model, as a possible mechanism underlying the favorable effect of exercise on AD. Forty male Wistar albino rats 2-3 months old were subdivided randomly into two groups (n = 20 each): AD group (injected intraperitoneally with aluminum chloride (70 mg/kg/day) for 6 weeks) and Control group. Each group was subdivided into exercised or non-exercised group (n = 10 each). Exercised groups were subjected to a swimming protocol (60 min/day, 5 days/week, 4 weeks). Serum HPG hormones, hippocampal β-amyloid levels and Morris water-maze cognition were assessed. Results demonstrated higher levels of β-amyloid, gonadotropin releasing hormone (GnRH), luteinizing hormone (LH) and follicle stimulating hormone (FSH) together with lower testosterone levels and cognitive impairment in the AD rats compared to controls. Β-amyloid levels negatively correlated with testosterone levels and positively correlated with GnRH, LH and FSH among the AD rats. Higher testosterone and lower GnRH, LH, FSH and β-amyloid levels, as well as cognitive improvement, were observed in the exercised compared to non-exercised AD rats, suggesting a modulatory role of exercise training on AD-associated HPG axis dysregulation.

Effect of concurrent resistance-aerobic training on inflammatory factors and growth hormones in children with type 1 diabetes: a randomized controlled clinical trial

BACKGROUND

Exercise training is a major factor in controlling type 1 diabetes mellitus (T1DM) in children. The present study aimed to assess the effect of concurrent resistance-aerobic training on selected inflammatory factors and hormones related to blood glucose homeostasis in children with T1DM.

METHODS

In this randomized controlled clinical trial, 40 children (with the mean age of 11.11 ± 2.29 years) were randomly assigned to an experimental (N = 20) or control group (N = 20). They underwent a 16-week training program, composed of concurrent resistance-aerobic training performed intermittently for 60 min three times a week. Before and after training, blood samples were analyzed for glucose homeostasis, selected inflammatory factors, and growth factors. Data were analyzed by paired t-test and analysis of covariance (ANCOVA) in IBM SPSS version 22.

RESULTS

The exercise training intervention reduced fasting blood sugar index (P = 0.002) and glycosylated hemoglobin significantly (P = 0.003). The growth hormone levels were increased significantly only in the experimental group (P = 0.037), whereas no significant difference was noted in the insulin-like growth factor-1 (P = 0.712). It was also found that interleukin-1β and high-sensitivity C-reactive protein did not change in the experimental or control group as compared to the pretest (P > 0.05).

CONCLUSION

As it was shown, it seems that concurrent resistance-aerobic training may improve blood glucose homeostasis and growth hormone. Therefore, these findings may suggest the benefit from exercise training of moderate intensity in children with T1DM. Besides, we recommend undertaking further clinical trials to determine if the exercise training was effective.

TRIAL REGISTRATION

This study was registered in the Iranian Registry of Clinical Trials under the code IRCT20150531022498N30: https://en.irct.ir/trial/41031 . Registered on July 26, 2019. All experiments on the participants were following the Declaration of Helsinki.

Factors for optimizing intervention programs for cognition in older adults: the value of exergames

This review presents factors that could optimize the effectiveness of an intervention program on cognitive health in older adults. Combined, multi-dimensional and interactive programs appear to be relevant. On one hand, for the characteristics to be implemented in the physical dimension of a program, multimodal interventions stimulating the aerobic pathway and muscle strengthening during the solicitation of gross motor activities, seem to be interesting. On the other hand, regarding the cognitive dimension of a program, complex and variable cognitive stimuli appear to hold the greatest promise for generating cognitive benefits and the broadest transfers to untrained tasks. The field of video games also brings interesting enrichment through the gamification of situations and the feeling of immersion. However, some gray areas remain to be clarified, notably the ideal response dose, the balance between physical and cognitive solicitation and the programs’ customization.

Doping and sports endocrinology: growth hormone, IGF-1, insulin, and erythropoietin

Among the substances prohibited by the World Anti-Doping Agency, "peptide hormones, growth factors, related substances, and mimetics" are classified as prohibited both in- and out-of-competition in section S2. This work reviews growth hormone and its releasing peptides, insulin-like growth factor 1 as the main growth factor, insulin, and erythropoietin and other agents that affect erythropoiesis. This review analyzes the prevalence of use among professional athletes and gym clients, the forms of use, dosing, ergogenic effects and effects on physical performance, as well as side effects and anti-doping detection methods.

A machine-learning algorithm integrating baseline serum proteomic signatures predicts exercise responsiveness in overweight males with prediabetes

The molecular transducers conferring the benefits of chronic exercise in diabetes prevention remain to be comprehensively investigated. Herein, serum proteomic profiling of 688 inflammatory and metabolic biomarkers in 36 medication-naive overweight and obese men with prediabetes reveals hundreds of exercise-responsive proteins modulated by 12-week high-intensity interval exercise training, including regulators of metabolism, cardiovascular system, inflammation, and apoptosis. Strong associations are found between proteins involved in gastro-intestinal mucosal immunity and metabolic outcomes. Exercise-induced changes in trefoil factor 2 (TFF2) are associated with changes in insulin resistance and fasting insulin, whereas baseline levels of the pancreatic secretory granule membrane major glycoprotein GP2 are related to changes in fasting glucose and glucose tolerance. A hybrid set of 23 proteins including TFF2 are differentially altered in exercise responders and non-responders. Furthermore, a machine-learning algorithm integrating baseline proteomic signatures accurately predicts individualized metabolic responsiveness to exercise training.

The effect of Tai Chi in elderly individuals with sarcopenia and frailty: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The potential role of Tai Chi in improving sarcopenia and frailty has been shown in randomized controlled trials (RCTs). This systematic review and meta-analysis aimed to examine the effect of Tai Chi on muscle mass, muscle strength, physical function, and other geriatric syndromes in elderly individuals with sarcopenia and frailty.

METHODS

Systematic searches of the PubMed, Cochrane Library, PEDro, EMBASE, Web of Science, CINAHL, and Medline databases for RCTs published between 1989 and 2022 were conducted; the database searchers were supplemented with manual reference searches. The inclusion criteria were as follows: (1) the study was designed as a RCT; (2) Tai Chi was one of the intervention arms; (3) the participants had a minimum age of ≥ 60 years and were diagnosed with frailty or sarcopenia, and the diagnostic guidelines or criteria were mentioned; (4) the number of participants in each arm was ≥ 10; and (5) the outcome reports included ≥ 1 item from the following primary or secondary outcomes. The exclusion criteria were as follows: (1) non-RCT studies; (2) nonhuman subjects; (3) participants aged < 60 years; (4) no description of the diagnostic guidelines or criteria for frailty or sarcopenia in the text; and (5) reported outcomes not among the following primary or secondary outcomes. The primary outcomes were muscle mass, grip strength and muscle performance (gait speed, 30-second chair stand test (30CST), sit-to-stand test (SST), Timed up and go test (TUGT), balance, and the Short Physical Performance Battery (SPPB)). The secondary outcomes included the number of falls and fear of falling (FOF), diastolic blood pressure (DBP), Mini-Mental State Examination (MMSE) score, and depression and quality of life (QOL) assessments.

RESULTS

Eleven RCTs were conducted from 1996 to 2022 in 5 countries that investigated 1676 sarcopenic or frail elderly individuals were included in the review. There were 804 participants in the Tai Chi exercise cohort and 872 participants in the control cohort (nonexercised (n = 5)/ exercise (n = 8)). The mean age of participants was 70-89.5 years and the numbers of participants from each arm in each study were 10-158. The majority of the participants practiced Yang-style Tai Chi (n = 9), and the numbers of movement ranged from 6 to 24. The prescriptions of training were 8-48 weeks, 2-7 sessions per weeks, and 30-90 min per session. Most studies used Tai Chi expert as instructor (n = 8). The lengths of follow-up period were 8-48 weeks. The results from our meta-analysis revealed significant improvements for Tai Chi compared to control group (nonexercise/ exercise) on measures of the 30CST (weighted mean difference (WMD): 2.36, 95% confidence interval (CI) 1.50-3.21, p < 0.00001, I² = 87%), the TUGT (WMD: -0.72, 95% CI -1.10 to -0.34, p = 0.0002, I² =0%), numbers of fall (WMD: -0.41, 95% CI -0.64 to -0.17, p = 0.0006, I² =0%) and FOF (standardized MD (SMD): -0.50, 95% CI -0.79 to -0.22, p = 0.0006, I² = 57%); and for Tai Chi compared to 'nonexercise' controls on measures of SST (WMD: -2.20, 95% CI -2.22 to -2.18, p < 0.00001), balance (SMD: 9.85, 95% CI 8.88-10.82, p < 0.00001), DBP (WMD: -7.00, 95% CI -7.35 to -6.65, p < 0.00001), MMSE (WMD: 1.91, 95% CI 1.73-2.09, p < 0.00001, I² =0%), depression (SMD: -1.37, 95% CI -1.91 to -0.83, p < 0.00001) and QOL (SMD: 10.72, 95% CI 9.38-12.07, p < 0.00001). There were no significant differences between Tai Chi and control groups on any of the remaining 4 comparisons: body muscle mass (WMD: 0.53, 95% CI -0.18 to 1.24; P = 0.14; I² =0%), grip strength (WMD: -0.06, 95% CI -1.98 to 1.86; P = 0.95; I² =0%), gait speed (WMD: 0.05, 95% CI -0.11 to 0.20; P = 0.55; I² =99%), and SPPB (WMD: 0.55, 95% CI -0.04 to 1.14; P = 0.07). The variables of bias summary, Tai Chi instructor, Tai Chi movements, and Tai Chi training duration without significant association with the 30CST or the TUGT through meta-regression analyses.

CONCLUSIONS

Our results demonstrated that patients with frailty or sarcopenia who practiced Tai Chi exhibited improved physical performance in the 30-second chair stand test, the Timed up and go test, number of falls and fear of falling. However, there was no difference in muscle mass, grip strength, gait speed, or Short Physical Performance Battery score between the Tai Chi and control groups. Improvements in the sit-to-stand test, balance, diastolic blood pressure, Mini-Mental State Examination score, and depression and quality of life assessments were found when comparing the Tai Chi cohort to the nonexercise control cohort rather than the exercise control cohort. To explore the effectiveness of Tai Chi in sarcopenic and frail elderly individuals more comprehensively, a standardized Tai Chi training prescription and a detailed description of the study design are suggested for future studies.

Exogenous growth hormone promotes an epithelial-mesenchymal hybrid phenotype in cancerous HeLa cells but not in non-cancerous HEK293 cells

In cancer, the Epithelial to Mesenchymal Transition (EMT) is the process in which epithelial cells acquire mesenchymal features that allow metastasis, and chemotherapy resistance. Growth hormone (GH) has been associated with melanoma, breast, and endometrial cancer progression through an autocrine regulation of EMT. Since exogenous and autocrine expression of GH is known to have different molecular effects, we investigated whether exogenous GH is capable of regulating the EMT of cancer cells. Furthermore, we investigated whether exogenous GH could promote EMT in non-cancerous cells. To study the effect of GH (100 ng/ml) on cancer and non-cancer cells, we used HeLa and HEK293 cell lines, respectively. We evaluated the loss of cell-cell contacts, by cell scattering assay and migration by wound-healing assay. Additionally, we evaluated the morphological changes by phalloidin-staining. Finally, we evaluated the molecular markers E-cadherin and vimentin by flow cytometry. GH enhances cell scattering and the migratory rate and promotes morphological changes such as cell area increase and actin cytoskeleton filaments formation on HeLa cell line. Moreover, we found that GH favors the expression of the mesenchymal protein vimentin, followed by an increase in E-cadherin's epithelial protein expression, characteristics of an epithelial-mesenchymal hybrid phenotype that is associated with metastasis. On HEK293cells, GH promotes morphological changes, including cell area increment and filopodia formation, but not affects scattering, migration, nor EMT markers expression. Our results suggest that exogenous GH might participate in cervical cancer progression favoring a hybrid EMT phenotype but not on non-cancerous HEK293 cells.

A targeted metabolic analysis of football players and its association to player load: Comparison between women and men profiles

Professional athletes undertake a variety of training programs to enhance their physical performance, technical-tactical skills, while protecting their health and well-being. Regular exercise induces widespread changes in the whole body in an extremely complex network of signaling, and evidence indicates that phenotypical sex differences influence the physiological adaptations to player load of professional athletes. Despite that there remains an underrepresentation of women in clinical studies in sports, including football. The objectives of this study were twofold: to study the association between the external load (EPTS) and urinary metabolites as a surrogate of the adaptation to training, and to assess the effect of sex on the physiological adaptations to player load in professional football players. Targeted metabolic analysis of aminoacids, and tryptophan and phenylalanine metabolites detected progressive changes in the urinary metabolome associated with the external training load in men and women’s football teams. Overrepresentation analysis and multivariate analysis of metabolic data showed significant differences of the effect of training on the metabolic profiles in the men and women teams analyzed. Collectively, our results demonstrate that the development of metabolic models of adaptation in professional football players can benefit from the separate analysis of women and men teams, providing more accurate insights into how adaptation to the external load is related to changes in the metabolic phenotypes. Furthermore, results support the use of metabolomics to understand changes in specific metabolic pathways provoked by the training process.

The athletic characteristics of Olympic sports to assist anti-doping strategies

The determinants of success in Olympic Games competition are specific to the athletic demands of the sporting event. A global evaluation to quantify the athletic demands across the spectrum of the Olympic Games sport events has not previously been conducted. Thus far, the interpretation and the comparison of sport physiological characteristics within anti-doping organisations (ADOs) risk assessments remains subjective without a standardised framework. Despite its subjective assessment, this information is a key component of any anti-doping programme. Sport characteristics inevitably influence the type of substances and/or methods used for doping purpose and should be captured through a comprehensive analysis. Seven applied sport scientists independently conducted an assessment to quantify the athletic demands across six preselected athletic variables. A Principal Component Analysis was performed on the results of the panel's quantitative assessment for 160 Olympic Sport events. Sport events were clustered using the Hierarchical Density Based Spatial Clustering of Applications with Noise (HDBSCAN) algorithm. The HDBSCAN identified 19 independent cluster groups, 36 sport events remained statistically unassigned to a cluster group representing unique and eventspecific athletic demands. This investigation provides guidance to the anti-doping community to assist in the development of the sport specific physiology component of the risk assessment for Olympic Games disciplines. The dominant athletic characteristics to excel in each of these individual events will highlight areas of how athletes may strive to gain a competitive advantage through doping strategies, and inform the development of an effective and proportionate allocation of testing resources.

Biochemical discrepancies in the evaluation of the somatotroph axis: Elevated GH or IGF-1 levels do not always diagnose acromegaly

The most frequent diagnosis underlying the finding of an elevated growth hormone (GH) and insulin-like growth factor-1 (IGF-1) is acromegaly due to a GH-secreting pituitary tumour. However, GH and IGF-1 levels can be discordant in patients with acromegaly due to early or partially treated disease, or there might be another cause of high GH or high IGF-1 unrelated to acromegaly, such as pre-analytical and technical pitfalls, physiological circumstances and pathological conditions. High GH and normal or low serum IGF-1, or alternatively, normal GH with elevated serum IGF-1, should be carefully assessed to avoid misinterpreting the activity of acromegaly or misdiagnosing a patient with acromegaly. We summarise here these biochemical discrepancies in the evaluation of the somatotroph axis.

The Effects of Physical Exercise on Saliva Composition: A Comprehensive Review

Saliva consists of organic and inorganic constituents. During exercise, analysis of the saliva can provide valuable information regarding training stress, adaptation and exercise performance. The objective of the present article was to review the effect of physical exercise on saliva composition. The shift in the composition of the saliva, during and after a workout, reflects the benefits of exercise, its potential risks and the capability of the saliva to serve as a health indicator. The type and the frequency of training, the physical condition and the athletes’ general health influence the hormones, immunoglobulins and saliva enzymes. The correlation between saliva and physical exercise has to be further investigated and the available knowledge to be applied for the benefit of the athletes during sports activities.

The effect of the menstrual cycle on collagen metabolism, growth hormones and strength in young physically active women

This study aimed to investigate the effect of the menstrual cycle on strength, functioning of the GH/IGF-1 axis and collagen metabolism in physically active women. Twenty-four physically active and eumenorrheic women volunteered to participate in the study (body mass 60.3 ± 9.18 kg, age 21.8 ± 0.92 years). Blood samples were obtained between the 5th and 8th days (the follicular phase) and between the 19th and 22th days (the luteal phase) of the menstrual cycle to determine sex steroid concentrations (follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), oestradiol (E2) and progesterone (P)). Also insulin-like growth factor 1 (IGF-1) and collagen metabolism markers (synthesis (PICP) and breakdown (ICTP)) and maximum voluntary contraction (MVC) were measured. MVC was higher in the luteal phase 164.1 ± 34.77 [N m] (F(1.23) = 4.59; p = 0.043). The recorded collagen synthesis marker (PICP = 296.4 ± 35.61 [ng/ml]) was at the upper level of the reference range (30-300), with an insignificant decrease in the luteal phase (Z = 1.612; p = 0.107) and a significant increase in oestradiol concentration (Z = 4.286; p = 0.0001). The marker of collagen breakdown (ICTP = 4.16 ± 0.68 [μg/l]) was reduced by 6.8% in the same phase (Z = 1.764; p = 0.137). The variability of physical abilities (MVC) during the menstrual cycle showed that menstrual status should be taken into account in determination of the training loads. Increasing the load in the luteal phase seems to be favoured by a beneficial change in collagen metabolism (lower synthesis decrease, lower breakdown increase) observed in physically active women.

Time-of-Day Effects on Anaerobic Power and Concentration of Selected Hormones in Blind Men

Knowledge of the circadian rhythm of the blind person and diurnal changes in anaerobic power and hormones concentration can create the possibility of individualising physical training. The aim of the study was to examine the time-of-day effects on anaerobic performance and the concentration of selected hormones. The measurements were performed at two different times of the day (10:00 a.m., 10:00 p.m.) in blind men at the age of 20–25 years old. The experiment group was chosen by using repeated hormonal tests four times a day so that each selected patient had a sleep/wake cycle even of 24 h. Anaerobic peak power and total work were tested in an anaerobic sprint test, and the concentration of growth hormone, testosterone, cortisol, and melatonin was determined. In blind men, the hormonal response was not driven by the photoperiod as in the control group. In the blind group, at 10:00 p.m., anaerobic peak power and total work results were significantly higher than at 10:00 a.m. and negatively correlated with melatonin levels. No such correlation was found in the control group.

Hormonal and Metabolic Changes of Aging and the Influence of Lifestyle Modifications

Increased life expectancy combined with the aging baby boomer generation has resulted in an unprecedented global expansion of the elderly population. The growing population of older adults and increased rate of age-related chronic illness has caused a substantial socioeconomic burden. The gradual and progressive age-related decline in hormone production and action has a detrimental impact on human health by increasing risk for chronic disease and reducing life span. This article reviews the age-related decline in hormone production, as well as age-related biochemical and body composition changes that reduce the bioavailability and actions of some hormones. The impact of hormonal changes on various chronic conditions including frailty, diabetes, cardiovascular disease, and dementia are also discussed. Hormone replacement therapy has been attempted in many clinical trials to reverse and/or prevent the hormonal decline in aging to combat the progression of age-related diseases. Unfortunately, hormone replacement therapy is not a panacea, as it often results in various adverse events that outweigh its potential health benefits. Therefore, except in some specific individual cases, hormone replacement is not recommended. Rather, positive lifestyle modifications such as regular aerobic and resistance exercise programs and/or healthy calorically restricted diet can favorably affect endocrine and metabolic functions and act as countermeasures to various age-related diseases. We provide a critical review of the available data and offer recommendations that hopefully will form the groundwork for physicians/scientists to develop and optimize new endocrine-targeted therapies and lifestyle modifications that can better address age-related decline in heath.

Distribution of growth hormone-responsive cells in the brain of rats and mice

A growth hormone (GH) injection is able to induce the phosphorylated form of the signal transducer and activator of transcription 5 (pSTAT5) in a large number of cells throughout the mouse brain. The present study had the objective to map the distribution of GH-responsive cells in the brain of rats that received an intracerebroventricular injection of GH and compare it to the pattern found in mice. We observed that rats and mice exhibited a similar distribution of GH-induced pSTAT5 in the majority of areas of the telencephalon, hypothalamus and brainstem. However, rats exhibited a higher density of GH-responsive cells than mice in the horizontal limb of the diagonal band of Broca (HDB), supraoptic and suprachiasmatic nuclei, whereas mice displayed more GH-responsive cells than rats in the hippocampus, lateral hypothalamic area and dorsal motor nucleus of the vagus (DMX). Since both HDB and DMX contain acetylcholine-producing neurons, pSTAT5 was co-localized with choline acetyltransferase in GH-injected animals. We found that 50.0 ± 4.5% of cholinergic neurons in the rat HDB coexpressed GH-induced pSTAT5, whereas very few co-localizations were observed in the mouse HDB. In contrast, rats displayed fewer cholinergic neurons responsive to GH in the DMX at the level of the area postrema. In summary, pSTAT5 can be used as a marker of GH-responsive cells in the rat brain. Although rats and mice exhibit a relatively similar distribution of GH-responsive neurons, some species-specific differences exist, as exemplified for the responsiveness to GH in distinct populations of cholinergic neurons.

Inflammation, Peripheral Signals and Redox Homeostasis in Athletes Who Practice Different Sports

The importance of training in regulating body mass and performance is well known. Physical training induces metabolic changes in the organism, leading to the activation of adaptive mechanisms aimed at establishing a new dynamic equilibrium. However, exercise can have both positive and negative effects on inflammatory and redox statuses. In recent years, attention has focused on the regulation of energy homeostasis and most studies have reported the involvement of peripheral signals in influencing energy and even inflammatory homeostasis due to overtraining syndrome. Among these, leptin, adiponectin, ghrelin, interleukin-6 (IL6), interleukin-1β (IL1β) and tumour necrosis factor a (TNFa) were reported to influence energy and even inflammatory homeostasis. However, most studies were performed on sedentary individuals undergoing an aerobic training program. Therefore, the purpose of this review was to focus on high-performance exercise studies performed in athletes to correlate peripheral mediators and key inflammation markers with physiological and pathological conditions in different sports such as basketball, soccer, swimming and cycling.

Neurochemical phenotype of growth hormone-responsive cells in the mouse paraventricular nucleus of the hypothalamus

Multiple neuroendocrine, autonomic and behavioral responses are regulated by the paraventricular nucleus of the hypothalamus (PVH). Previous studies have shown that PVH neurons express the growth hormone (GH) receptor (GHR), although the role of GH signaling on PVH neurons is still unknown. Given the great heterogeneity of cell types located in the PVH, we performed a detailed analysis of the neurochemical identity of GH-responsive cells to understand the possible physiological importance of GH action on PVH neurons. GH-responsive cells were detected via the phosphorylated form of the signal transducer and activator of transcription-5 (pSTAT5) in adult male mice that received an intraperitoneal GH injection. Approximately 51% of GH-responsive cells in the PVH co-localized with the vesicular glutamate transporter 2. Rare co-localizations between pSTAT5 and vesicular GABA transporter or vasopressin were observed, whereas approximately 20% and 38% of oxytocin and tyrosine hydroxylase (TH) cells, respectively, were responsive to GH in the PVH. Approximately 55%, 35% and 63% of somatostatin, thyrotropin-releasing hormone (TRH) and corticotropin-releasing hormone (CRH) neurons expressed GH-induced pSTAT5, respectively. Additionally, 8%, 49% and 75% of neuroendocrine TH, TRH and CRH neurons, and 67%, 32% and 74% of nonneuroendocrine TH, TRH and CRH neurons were responsive to GH in the PVH of Fluoro-Gold-injected mice. Our findings suggest that GH action on PVH neurons is involved in the regulation of the thyroid, somatotropic and adrenal endocrine axes, possibly influencing homeostatic and stress responses.

Insulin and Growth Hormone Balance: Implications for Obesity

Disruption of endocrine hormonal balance (i.e., increased levels of insulin, and reduced levels of growth hormone, GH) often occurs in pre-obesity and obesity. Using distinct intracellular signaling pathways to control cell and body metabolism, GH and insulin also regulate each other's secretion to maintain overall metabolic homeostasis. Therefore, a comprehensive understanding of insulin and GH balance is essential for understanding endocrine hormonal contributions to energy storage and utilization. In this review we summarize the actions of, and interactions between, insulin and GH at the cellular level, and highlight the association between the insulin/GH ratio and energy metabolism, as well as fat accumulation. Use of the [insulin]:[GH] ratio as a biomarker for predicting the development of obesity is proposed.

Influence of various environmental factors on the growth of children and adolescents in Jeddah, Kingdom of Saudi Arabia

Objectives:

To evaluate the association between various environmental factors and the anthropometric measurements of children and adolescents.

Methods:

This retrospective studywasperformed from September 2017 to April 2018 and included 393 children aged 2-18 years. Data were extracted through patient and/or parentinterviews and from medical records of endocrine ambulatory clinics.

Results:

Among underweight children, the proportion of mixed-fed children was the highest, and among normal weight children, most were either bottle-fed or mixed-fed. Most overweight children were mixed-fed, and most obese children were breastfed. Underweight status was noted most commonly in children playing videogames for <2 hours/day, followed by those playing>4 and 2-4 hours/day. Normal weight was noted most commonly in those playing for >4 hours/day, followed by those playing <2 and 2-4 hours/day. Overweight status was noted most commonly in those playing videogames for >4 hours/day, followed by those playing 2-4 and <2 hours/day. Most children playing videogames for <2 hours/day were obese. Mean BMIs were the highest in those who exercised 1-2 times/week. P-values for the association between passive smoking indoors and BMI, weight, and height were 0.045, 0.150, and 0.854, respectively. Regarding socioeconomic status, log BMI values were 1.22, 1.23, and 1.26 in low-, medium-, and high-income families, respectively (P-value, 0.001).

Conclusion:

Children who were bottle-fed in their first year of life, played video games >2 hours/day, did not exercise regularly, were exposed to indoor passive smoking, and had a high socioeconomic status had a higher BMI and weight than their counterparts. (www.actabiomedica.it)

Links Between Testosterone, Oestrogen, and the Growth Hormone/Insulin-Like Growth Factor Axis and Resistance Exercise Muscle Adaptations

Maintenance of skeletal muscle mass throughout the life course is key for the regulation of health, with physical activity a critical component of this, in part, due to its influence upon key hormones such as testosterone, estrogen, growth hormone (GH), and insulin-like growth factor (IGF). Despite the importance of these hormones for the regulation of skeletal muscle mass in response to different types of exercise, their interaction with the processes controlling muscle mass remain unclear. This review presents evidence on the importance of these hormones in the regulation of skeletal muscle mass and their responses, and involvement in muscle adaptation to resistance exercise. Highlighting the key role testosterone plays as a primary anabolic hormone in muscle adaptation following exercise training, through its interaction with anabolic signaling pathways and other hormones via the androgen receptor (AR), this review also describes the potential importance of fluctuations in other hormones such as GH and IGF-1 in concert with dietary amino acid availability; and the role of estrogen, under the influence of the menstrual cycle and menopause, being especially important in adaptive exercise responses in women. Finally, the downstream mechanisms by which these hormones impact regulation of muscle protein turnover (synthesis and breakdown), and thus muscle mass are discussed. Advances in our understanding of hormones that impact protein turnover throughout life offers great relevance, not just for athletes, but also for the general and clinical populations alike.

Oxidative stress in exercise training: the involvement of inflammation and peripheral signals

The evidence about the health benefits of regular physical activity is well established. Exercise intensity is a significant variable and structured high-intensity interval training (HIIT) has been demonstrated to improve both whole-body and skeletal muscle metabolic health in different populations. Conversely, fatigue accumulation, if not resolved, leads to overwork, chronic fatigue syndrome (CFS), overtraining syndrome up to alterations of endocrine function, immune, systemic inflammation, and organic diseases with health threat. In response to temporary increases in stress during training, some athletes are unable to maintain sufficient caloric intake, thus suffering a negative energy balance that causes further stress. The regulation of the energy balance is controlled by the central nervous system through an elaborate interaction of the signalling that involves different tissues such as leptin, adiponectin and ghrelin whose provide important feedback to the hypothalamus to regulate the energy balance. Although exercise-induced reactive oxygen species are required for normal force production in muscle, high levels of ROS appear to promote contractile dysfunction. However, a high level of oxidative stress in may induce a rise in inflammatory markers and a disregulation in expression of adiponectin, leptin and grelin.

Resting Level of Insulin-Like Growth Factor-1 Is Not at Play in Cardiac Enlargement in Endurance-Trained Adolescents

Purpose

The study aimed to investigate resting levels of several selected growth and metabolic hormones in a group of 24 endurance-trained adolescents (aged 13–19 years) compared with 24 untrained age- and sex-matched controls, and to investigate if increased cardiac dimensions were related to these hormones at rest with emphasis on insulin-like growth factor-1 (IGF-1).

Methods

The hormones (cortisol, IGF-1, IGF-2, follicle-stimulating hormone, growth hormone, luteinizing hormone, prolactin, and thyroid-stimulating hormone) were analysed with chemiluminescence microparticle immunoassay (CMIA) or multiplex fluorochrome (Luminex) technique. Cardiac dimensions were assessed by echocardiographic examination at rest. Peak oxygen uptake was obtained by a maximal cardiopulmonary exercise test on a treadmill.

Results

Circulating levels of analysed hormones at rest did not differ between the groups. A correlation was found between increased cardiac dimensions and IGF-1 in the controls, but not in the active group. This correlation declined also among the controls when the cardiac parameters were indexed for body surface area.

Conclusion

Increased cardiac dimensions in endurance-trained adolescents could not be related to resting levels of hormones associated with growth and metabolism, including IGF-1 and GH. In addition, the resting levels of these hormones seem not to be affected by intense regular endurance exercise in adolescents. These findings may contribute to the knowledge about cellular signaling that trigger growth as well as cardiac adaptation to endurance training in young athletes.

The Use and Abuse of Growth Hormone in Sports

GH is banned by the World Anti-Doping Agency as a performance-enhancing anabolic agent. Doping with GH likely began in the early 1980s and became more prevalent with the advent of recombinant technology well before any scientific evidence of benefit. The expectation that GH improves physical function stems from its anabolic and lipolytic properties. Athletic performance depends on muscle strength and the energy required to power muscle function. In recreational athletes, GH selectively improves anaerobic sprint capacity but has not been proven to significantly enhance muscle strength, power, or maximum rate of oxygen consumption. GH is secreted as a family of isoform peptides in a pulsatile manner reflecting intermittent secretion and rapid clearance. Its anabolic actions are largely mediated by IGF-I, which stimulates whole-body protein synthesis, including skeletal muscle and collagen proteins. Two methods have been validated for detecting GH abuse in athletes. The first (the isoform method) is based on distinguishing pure recombinant 22-kDa GH from the heterogeneous isoforms secreted from the pituitary. The second (the marker method) is based on measuring blood levels of GH-responsive proteins, specifically IGF-I and the N-terminal propeptide of type III collagen (P-III-NP). Only a handful of athletes have been caught since the implementation of GH doping tests in 2004. The low rate likely reflects the limitation of in-competition testing using current methods. Improved detection rates may be achieved by more out-of-competition testing, introducing athletes' biological passports, and the development of novel methods. Governance, operational, technical, and political factors influence the effectiveness of an anti-doping program.

Effects of Boxing Matches on Metabolic, Hormonal, and Inflammatory Parameters in Male Elite Boxers

Background and objectives: Boxing is a popular combat sport that requires high intensity and cooperation. However, there are limited data about the influence of boxing matches on blood parameters. The purpose of the present study was to investigate the match-induced changes in the metabolic, hormonal, and inflammatory status in male elite boxers. Materials and methods: High-level 20 male boxers with more than 5 years experience in boxing voluntarily participated in this study. Venous blood samples of the boxers, before and after combat, were taken for determination of the plasma parameters. Results: Our results indicated that a 9-min boxing match caused significant increases in plasma energy fuels (glucose and lactate), metabolic hormones (insulin, adrenocorticotropic hormone (ACTH), cortisol, and growth hormone), inflammatory markers (interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α)), muscle damage indicators (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)), and oxidative stress marker (SOD). A decrease in total oxidant status (TOS) was also considered. However, there were no significant alterations in the plasma levels of androgenic hormone (free and total testosterone), anabolic hormone (IGF-1), lipids (total cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)), kidney function markers (creatinine and urea), and minerals (iron (Fe) and magnesium (Mg)). Conclusion: Elevations in the level of energy fuels and metabolic hormones of the boxers could be taken as a reflection of high-energy turnover during combat performance. The increases in inflammatory and tissue damage indicators may possibly be an indication of traumatic injury. Understanding the biochemical changes that occur during boxing match could be valuable to optimize the performance improvement of the athletes.

Effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue: analysis by Raman spectroscopy, dual-energy X-ray absorptiometry, and mechanical resistance

The aim of the present study was to verify the effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue by Raman spectroscopy (Raman), dual-energy X-ray absorptiometry (DXA), and mechanical resistance (F-max) analysis. A total of 40 male Wistar animals, 60 days old, were used. The animals were distributed into four groups: control (C), control with GH (GHC), muscular strength training (T), and muscular strength training with GH (GHT). Blood samples were collected for the quantification of creatine kinase (CK-MB) and the femurs were removed for analysis by Raman, DXA, and F-max. A more pronounced increase in the bone mineral components was verified in the T group, for all the variables obtained by the Raman (calcium, phosphate, amide, and collagen). In addition, for animals submitted to GH supplementation, there was a reduction in the variable bone mineral density (BMD) obtained by the DXA (p < 0.05). Finally, the animals that received GH supplementation presented a higher F-max, but without statistical significance (p > 0.05). It was concluded that animals that received GH supplementation demonstrated a decrease in BMD. In addition, T alone was able to promote increased calcium, phosphate, amide, and collagen compounds in bone tissue.

Oral Supplementation Using Gamma-Aminobutyric Acid and Whey Protein Improves Whole Body Fat-Free Mass in Men After Resistance Training

Background

Oral gamma-aminobutyric acid (GABA) supplementation increases growth hormone (GH) serum levels and protein synthesis. Therefore, post-exercise supplementation using GABA and protein may help enhance training-induced muscle hypertrophy. We evaluated whether GABA with whey protein enhanced muscular hypertrophy in men after progressive resistance training.

Methods

Twenty-one healthy men (26 - 48 years) were randomized to receive whey protein (WP; 10 g) or whey protein + GABA (WP + GABA; 10 g + 100 mg) daily for 12 weeks. Both groups performed resistance training twice per week (three sets of 12 repetitions at 60% of maximal strength; leg press, leg extension, leg curl, chest press, and pull down). Body composition was assessed using dual-energy X-ray absorptiometry.

Results

In the WP + GABA group, resting plasma GH concentrations were significantly elevated at 4 and 8 weeks, compared to baseline. However, resting plasma GH concentrations in the WP group were only significantly elevated at 8 weeks. After 12 weeks, the WP + GABA group exhibited significantly greater increase in whole body fat-free mass than the WP group.

Conclusions

The GABA and whey protein combination was more effective for increasing whole body fat-free mass; daily GABA supplementation may help enhance exercise-induced muscle hypertrophy.

Human Physiology During Exposure to the Cave Environment: A Systematic Review With Implications for Aerospace Medicine

Background: Successful long-duration missions outside low-Earth orbit will depend on technical and physiological challenges under abnormal environmental conditions. Caves, characterized by absence of light, confinement, three-dimensional human movement and long-duration isolation, are identifiably one of the earliest examples of scientific enquiry into space analogs. However, little is known about the holistic human physiological response during cave exploration or prolonged habitation.

Objectives: The aim of our review was to conduct a systematic bibliographic research review of the effects of short and prolonged exposure to a cave environment on human physiology, with a view to extend the results to implications for human planetary exploration missions.

Methods: A systematic search was conducted following the structured PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for electronic databases.

Results: The search retrieved 1,519 studies. There were 50 articles selected for further consideration, of which 31 met our inclusion criteria. Short-term cave exposure studies have investigated visual dysfunction, cardiovascular, endocrine-metabolic, immunologic-hematological and muscular responses in humans. Augmentations of heart rate, muscular damage, initial anticipatory stress reaction and inflammatory responses were reported during caving activity. Prolonged exposure studies mainly investigated whether biological rhythms persist or desist in the absence of standard environmental conditions. Changes were evident in estimated vs. actual rest-activity cycle periods and external desynchronization, body temperature, performance reaction time and heart rate cycles. All studies have shown a marked methodological heterogeneity and lack reproduction under controlled conditions.

Conclusions: This review facilitates a further comparison of the proposed physiological impact of a subterranean space analog environment, with existing knowledge in related disciplines pertaining to human operative preparation under challenging environmental conditions. This comprehensive overview should stimulate more reproducible research on this topic and offer the opportunity to advance study design and focus future human research in the cave environment on noteworthy, reproducible projects.

Pilot study: an acute bout of high intensity interval exercise increases 12.5 h GH secretion

The purpose of this study was to test the hypothesis that high‐intensity interval exercise (HIE) significantly increases growth hormone (GH) secretion to a greater extent than moderate‐intensity continuous exercise (MOD) in young women. Five young, sedentary women (mean ± SD; age: 22.6±1.3 years; BMI: 27.4±3.1 kg/m²) were tested during the early follicular phase of their menstrual cycle on three occasions. For each visit, participants reported to the laboratory at 1700 h, exercised from 1730–1800 h, and remained in the laboratory until 0700 h the following morning. The exercise component consisted of either 30‐min of moderate‐intensity continuous cycling at 50% of measured peak power (MOD), four 30‐s “all‐out” sprints with 4.5 min of active recovery (HIE), or a time‐matched sedentary control using a randomized, cross‐over design. The overnight GH secretory profile of each trial was determined from 10‐min sampling of venous blood from 1730–0600 h, using deconvolution analysis. Deconvolution GH parameters were log transformed prior to statistical analyses. Calculated GH AUC (0–120 min) was significantly greater in HIE than CON (P = 0.04), but HIE was not different from MOD. Total GH secretory rate (ng/mL/12.5 h) was significantly greater in the HIE than the CON (P = 0.05), but MOD was not different from CON or HIE. Nocturnal GH secretion (ng/mL/7.5 h) was not different between the three trials. For these women, in this pilot study, a single bout of HIE was sufficient to increase 12.5 h pulsatile GH secretion. It remains to be determined if regular HIE may contribute to increased daily GH secretion.

Dietary Creatine Supplementation in Gilthead Seabream (Sparus aurata) Increases Dorsal Muscle Area and the Expression of myod1 and capn1 Genes

Creatine (Cr) is an amino acid derivative with an important role in the cell as energy buffer that has been largely used as dietary supplement to increase muscle strength and lean body mass in healthy individuals and athletes. However, studies in fish are scarce. The aim of this work is to determine whether dietary Cr supplementation affects muscle growth in gilthead seabream (Sparus aurata) juveniles. Fish were fed ad libitum for 69 days with diets containing three increasing levels of creatine monohydrate (2, 5, and 8%) that were compared with a non-supplemented control (CTRL) diet. At the end of the trial, the fast-twist skeletal muscle growth dynamics (muscle cellularity) and the expression of muscle-related genes were evaluated. There was a general trend for Cr-fed fish to be larger and longer than those fed the CTRL, but no significant differences in daily growth index (DGI) were registered among dietary treatments. The dorsal cross-sectional muscle area (DMA) of fish fed Cr 5 and Cr 8% was significantly larger than that of fish fed CTRL. The groups supplemented with Cr systematically had a higher relative number of both small-sized (≤20 μm) and large-sized fibers (≥120 μm). Dorsal total fibers number was highest in fish fed 5% Cr. In fish supplemented with 5% Cr, the relative expression of myogenic differentiation 1 (myod1) increased almost four times compared to those fed the CTRL diet. The relative expression of calpain 3 (capn3) was highest in fish fed diets with 2% Cr supplementation, but did not differ significantly from those fed the CTRL or Cr 5%. The myod1 gene expression had a positive and significant correlation with that of capn1, capns1a, and capn3 expression. These results suggest that the observed modulation of gene expression was not enough to produce a significant alteration in muscle phenotype under the tested conditions, as a non-significant increase in muscle fiber diameter and higher total number of fiber was observed, but still resulted in increased DMA. Additional studies may be required in order to better clarify the effect of dietary Cr supplementation in fish, possibly in conjunction with induced resistance training.

Obese adolescents exhibit a constant ratio of GH isoforms after whole body vibration and maximal voluntary contractions

BACKGROUND

Growth hormone (GH) is a heterogeneous protein composed of several molecular isoforms, the most abundant ones being the 22 kDa- and 20 kDa-GH. Exercise-induced secretion of GH isoforms has been extensively investigated in normal-weight individuals due to antidoping purposes, particularly recombinant human GH (rhGH) abuse. On the other hand, the evaluation of exercise-induced responses in GH isoforms has never been performed in obese subjects.

METHODS

The acute effects of whole body vibration (WBV) or maximal voluntary contraction (MVC) alone and the combination of MVC with WBV (MVC + WBV) on circulating levels of 22 kDa- and 20 kDa-GH were evaluated in 8 obese male adolescents [mean age ± SD: 17.1 ± 3.3 yrs.; weight: 107.4 ± 17.8 kg; body mass index (BMI): 36.5 ± 6.6 kg/m²; BMI standard deviation score (SDS): 3.1 ± 0.6].

RESULTS

MVC (alone or combined with WBV) significantly stimulated 22 kDa- and 20 kDa-GH secretion, while WBV alone was ineffective. In particular, 22 kDa- and 20 kDa-GH peaks were significantly higher after MVC + WBV and MVC than WBV. In addition, 22 kDa-GH (but not 20 kDa-GH) peak was significantly higher after MVC + WBV than MVC. Importantly, the ratio of circulating levels of 22 kDa- to 20 kDa-GH was constant throughout the time window of evaluation after exercise and similar among the three different protocols of exercise.

CONCLUSIONS

The results of the present study confirm the ability of MVC, alone and in combination with WBV, to stimulate both 22 kDa- and 20 kDa-GH secretion in obese patients, these responses being related to the exercise workload. Since the ratio of 22 kDa- to 20 kDa-GH is constant after exercise and independent from the protocols of exercise as in normal-weight subjects, hyposomatotropism in obesity does not seem to depend on an unbalance of circulating GH isoforms. Since the present study was carried out in a small cohort of obese sedentary adolescents, these preliminary results should be confirmed in further future studies enrolling overweight/obese subjects with a wider age range.

Association of circular Klotho and insulin-like growth factor 1 with cardiac hypertrophy indexes in athlete and non-athlete women following acute and chronic exercise

Owing to the role of insulin-like growth factor 1 (IGF-I) in cardiac hypertrophy and the ability of Klotho in inhibiting the IGF-I action, we investigated effects of exercise on plasma Klotho and IGF-I and their association with cardiac hypertrophy. In this study, 10 non-athlete and 10 athlete women underwent a Bruce test (acute exercise) and 12-weeks water aerobics training (chronic exercise). Electrocardiographic parameters, plasma IGF-I and Klotho levels were measured in different time courses. The exercise training could significantly increase left ventricular end-diastolic diameter index (LVEDDI) in the non-athletes. Plasma levels of IGF-I significantly increased following acute and chronic exercises. The Klotho levels at the baseline were higher in athletes than non-athletes and its levels significantly increased immediately after acute exercise in both groups. The Klotho levels significantly decreased in non-athletes 24 h after chronic exercise, but its level was still higher than the baseline in the athletes. We found positive and negative correlations between cardiac hypertrophy indexes (LVEDDI and left ventricular mass index) with respectively IGF-I and Klotho. In conclusion, we found a stimulatory effect of acute and chronic exercises on plasma IGF-I and Klotho and association of IGF-I with exercise-induced cardiac hypertrophy. Moreover, Klotho could act as a negative regulator for exercise-induced cardiac hypertrophy.

Sleep environments and sleep physiology: A review

Sleep loss impairs task performance and post-physical activity recovery, cognitive performance and mood, heightens fatigue and decreases vigour; poor sleep quality impairs decision-making, the speed and accuracy of task performance, and post-exercise recovery. Sleep time and quality are affected by age, psychological and physiological conditions, culture and environmental factors. Skin temperature, rapid temperature change and sweating during sleep can significantly reduce sleep quality. Hence, the thermal properties of bedding and sleepwear, both in steady-state and transient ambient temperature conditions, are logically important factors. Research to date on sleeping thermal microclimates and their effect on sleep quality is scarce. This present review covers the fundamental elements of human sleep, highlighting physically active people, such as athletes, and the influence of sleepwear and bedding on sleep thermal microclimates, as well as the research methods that have been and could be used in this field. This review identifies opportunity for future research direction and approaches to understanding thermal environments that may support better human sleep.

GH responses to whole body vibration alone or in combination with maximal voluntary contractions in obese male adolescents

BACKGROUND

The anabolic, lipolytic and anti-inflammatory effects of exercise-stimulated GH secretion could be usefully exploited in the multidisciplinary rehabilitative programs of obese patients, who are reported to suffer from hyposomatotropism. To date, evaluation of GH responses to whole body vibration (WBV) in combination with maximal voluntary contractions (MVC) has been performed in normal-weight subjects, but not obese patients. Thus, aim of the present study was to investigate the effects of WBV and MVC, alone and combined, on GH responsiveness in obese subjects.

METHODS

The acute effects of WBV or MVC alone and the combination of MVC with WBV (MVC + WBV) on serum GH, cortisol and IGF-I and blood lactate (LA) levels were evaluated in 8 obese male adolescents [mean age ± SD: 17.1 ± 3.3 yrs.; weight: 107.4 ± 17.8 kg; body mass index (BMI): 36.5 ± 6.6 kg/m²; BMI standard deviation score (SDS): 3.1 ± 0.6].

RESULTS

WBV and MVC (alone or combined) significantly stimulated GH secretion. In particular, GH peaks and net areas under the curve (nAUCs) were significantly higher after MVC + WBV and MVC than WBV, without any difference between MVC + WBV and MVC groups; anyway, an additive effect on GH levels immediately after the execution of MVC + WBV test was found in comparison with MVC test. LA peaks significantly increased after each exercise (vs. basal condition), being significantly higher after MVC + WBV and MVC than WBV, without any difference between MVC + WBV and MVC groups. Peak LA values were significantly correlated with GH peaks and nAUCs. In contrast to the unchanged IGF-I levels, MVC + WBV and MVC (but not WBV) significantly stimulated cortisol secretion.

CONCLUSIONS

The results of the present study confirm the ability of MVC and WBV to stimulate GH secretion in obese patients. Rehabilitative programs combining different types of exercise eliciting a potent GH response seem to be important to counteract the hyposomatotropism of obese patients. Due to its limited stress upon joints without provoking an excessive fatigue, WBV could be usefully employed in the initial stages of a weight loss program alone or in combination with more potent GH releasing stimuli, such as MVC.

Power Production and Biochemical Markers of Metabolic Stress and Muscle Damage Following a Single Bout of Short-Sprint and Heavy Strength Exercise in Well-Trained Cyclists

Purpose: Although strength and sprint training are widely used methods in competitive cycling, no previous studies have compared the acute responses and recovery rates following such sessions among highly trained cyclists. The primary aim of the current study was to compare power production and biochemical markers of metabolic stress and muscle damage following a session of heavy strength (HS) and short-sprint training (SS).

Methods: Eleven well-trained male cyclists (18 ± 2 years with maximal oxygen uptake of 67.2 ± 5.0 mL·kg⁻¹·min⁻¹) completed one HS session and one SS session in a randomized order, separated by 48 h. Power production and biochemical variables were measured at baseline and at different time points during the first 45 h post exercise.

Results: Lactate and human growth hormone were higher 5 min, 30 min and 1 h post the SS compared to the HS session (all p ≤ 0.019). Myoglobin was higher following the HS than the SS session 5 min, 30 min and 1 h post exercise (all p ≤ 0.005), while creatine kinase (CK) was higher following the HS session 21 and 45 h post exercise (p ≤ 0.038). Counter movement jump and power production during 4 sec sprint returned to baseline levels at 23 and 47 h with no difference between the HS and SS session, whereas the delayed muscle soreness score was higher 45 h following the HS compared to the SS session (p = 0.010).

Conclusion: Our findings indicate that SS training provides greater metabolic stress than HS training, whereas HS training leads to more muscle damage compared to that caused by SS training. The ability to produce power remained back to baseline already 23 h after both training sessions, indicating maintained performance levels although higher CK level and muscle soreness were present 45 h post the HS training session.

The effects of Panax ginseng supplementation on growth hormone, cortisol and lactate response to high-intensity resistance exercise

Study aim: Growth hormone, cortisol, and lactate play an effective role in regulating and stimulating the muscle building proc­ess. The current study aimed to investigate the impact of Panax ginseng supplementation on growth hormone, cortisol, and lactate response to intense resistance exercise in young female non-athletes. Materials and methods: Ten non-athlete girls participated in this double-blind counter-balanced crossover study. They were assigned to two groups: the ginseng group and the placebo group. In two 4-week periods, they received the supplement and the placebo. In the first four weeks, 5 participants received ginseng (100 mg daily) and 5 others received placebo (maltodextrin). At the end of the 4 weeks, blood samples (5 ml) were taken to measure blood levels of the factors. Afterwards, the resistance exercise protocol was implemented, and immediately after that blood samples were taken. In the second four-week period, the five participants who had taken ginseng received placebo, and the five subjects who had received placebo took ginseng. The same tests were administered again. Results: The results showed that except for cortisol in the ginseng group, there were significant pre - to post-exercise changes for all 3 indicators in both groups. No significant difference was observed in pre - to post-exercise changes in the levels of GH (p = 0.71), cortisol (p = 0.34), or lactate (p = 0.90) between groups. Conclusions: 100 mg ginseng consumption daily for 4 weeks does not have an impact on the response of GH, cortisol, or lac­tate to high-intensity resistance exercise in young female non-athletes.