Leptin and exercise

Systemic Responses Towards Oxy-Inflammation, Hormones, and Mood in Breast Cancer Survivors: Preliminary Evidences from Dragon Boat Endurance Race

Background/Objectives: Endurance exercise increases oxygen demand and, when not balanced by antioxidant defenses, consequently, oxidative stress and inflammatory cytokines increase too. In breast cancer survivors (BCS), post-treatment, physical capacity decreases, lowering life quality. Dragon boat (DB) paddling has shown benefits in reducing lymphedema and improving psychological well-being. This study aimed at non-invasively investigating in BCS, by means of saliva and urine samples, the systemic responses to oxy-inflammation, and appetite hormones after a DB endurance race. Methods: 15 BCS and 15 healthy women (5 (CTR) who performed the DB race too) were studied. BCS and CTR were monitored pre- and post-race. Reactive oxygen species (ROS) production, total antioxidant capacity (TAC), lipid peroxidation (8-iso), DNA oxidation (8-OH-dG), nitric oxide metabolites (NOx), inflammation markers (IL-6-10 and TNFα), appetite hormones, electrolytes concentration, psychometric, and physical scales were assessed. Results: At rest, compared to healthy women, BCS showed a significant increase in oxy-inflammation biomarkers. BCS showed a general increase in oxy-inflammation parameters compared to CTR after the DB race. In BCS, there were the following results: ROS: +80%; lipid peroxidation: +103%; DNA oxidation: +44%; interleukins-6: +179%; IL-10: +55%; TNFα: +9%, NOx: +60% increases and unbalanced appetite hormones: leptin (-32%); and ghrelin (+53%). Moreover, the dragon boat offered a holistic approach to recovery, addressing emotional and social needs supporting belonging, love, and esteem needs, reported to be about 56% of the motivations in this activity, while post-race the following increased: a sense of fatigue (+55%); tiredness (48%); a cold sensation (+15%); and +32% pain. Conclusions: This study provided evidence that, in BCS, a DB endurance race produces an important imbalance in the oxy-inflammation state, at the same time being accompanied by a positive impact on subjective mood and general wellness. Future studies should focus on long-term effects.

Hormonal and Glycemic Responses During and After Constant- and Alternating-Intensity Exercise

Background/Objectives: Glucose metabolism and hormonal responses are largely affected by exercise intensity, which exhibits an alternating pattern in many sports activities. The aim of this study was to investigate and compare glycemic and hormonal responses during and after exercise of constant (CON) and alternating (ALT) intensity with the same duration and total work. Methods: Ten healthy male volunteers performed two, 60 min cycling exercise bouts in random order: the ALT bout, where exercise intensity alternated between 46.5 ± 1.9% of VO2max for 40 s and 120% of VO2max for 20 s, so the mean intensity was at 105% of the lactate threshold (LT), and the CON exercise bout, where the intensity was constant at 105% of LT (70 ± 4.7% of VO2max). Results: No significant differences were observed in blood glucose concentrations between the two exercise protocols (p = 0.22) or over time at any time point measured, i.e., before, at 30 and 60 min of each exercise bout, and 60 min post-exercise (p > 0.05). Circulating insulin levels decreased significantly over time in both protocols (p < 0.01 and p < 0.05 in ALT and CON, respectively); nevertheless, they did not differ between the exercise protocols (p = 0.45). Similarly, there were no significant differences in serum leptin and prolactin levels between the two protocols (p = 0.77 and p = 0.80 in ALT and CON, respectively); however, circulating levels of leptin decreased at 30 and 60 min of exercise only in CON (p < 0.05) and those of prolactin at 60 min of exercise only in ALT (p < 0.05) compared to pre-exercise values. Conclusions: Cycling exercise of constant or alternating moderate intensity (~70% of VO2max) with the same duration induces similar glycemic but differential over time hormonal responses in healthy males.

Correlation of Adiponectin and Leptin with Anthropometrics and Behavioral and Physical Performance in Overweight and Obese Chinese College Students

The aim of this study is to assess the relationship of leptin (LEP) and adiponectin (ADPN) with other circulating fat markers, physical capacity, behaviors, and anthropometric indices in a population of overweight and obese Chinese university students. LEP and ADPN levels, as well as behavioral, anthropometric, biochemical, and performance characteristics, were measured.

METHOD

A total of 17 anthropometric parameters, 8 questionnaires (investigating quality of life, sleep, eating, perceived functioning, stress, and depression), 9 biochemical parameters, and 12 functional parameters were investigated.

RESULTS

In contrast to previous studies, our work found an unusually strong relationship between LEP and ADPN (r = 0.961, p = 0.000) that can be related to ethnicity. We also found that LEP and ADPN were associated with stress and bodily pain. A total of 12 anthropometric measures were also associated with LEP/ADNP levels. Moreover, LEP and ADPN were found to be related to lower limb, hand, and abdominal strength; blood pressure; and basic metabolism. However, we did not find associations with sleep; eating habits; or cardiovascular fitness, which was measured in the form of resting heart rate and VO2max.

CONCLUSION

This study reveals new relationships of LEP and ADPN with selected anthropometric and behavioral parameters in obese Chinese college students.

The Beneficial Effects of Nordic Walking Training Combined with Time-Restricted Eating 14/24 in Women with Abnormal Body Composition Depend on the Application Period

The aim of the study was to assess the impact of two lengths of Nordic walking (NW) training interventions combined with time-restricted eating (TRE) on improving body-composition parameters, lipid profiles, and levels of selected adipokines in women with elevated body mass. Overweight and obese women (n = 55, age: 21-85) were recruited. Four groups were selected: 6 weeks (SG6, n = 13) and 12 weeks intervention (SG12, n = 13); and two control groups: CON6 (n = 13) and CON12 (n = 13). The training sessions took place three times a week (60 min each) and were conducted outdoors under the supervision of a professional coach. The training intensity was determined individually. The extended NW program combined with TRE induced a significant weight reduction in SG12 by 1.96 kg (p = 0.010) and fat tissue by 1.64 kg (p = 0.05). The proposed interventions did not affect LBM, TBW [kg], VFA, and lipid profile. The LDL/HDL ratio changed with a small size effect. The leptin concentration differed between groups (p = 0.006), but not over time. For resistin, the differentiating factor was time (p = 0.019), with lower results observed after the intervention. The change in leptin concentration was negatively correlated with its baseline concentration (p = 0.025). Extended to 12 weeks, this intervention allows for an improvement in body composition. Neither 6 nor 12 weeks of training and fasting affected the lipoprotein profile. It is, therefore, indicated to recommend prolonged training protocols and to inform patients that beneficial effects will be seen only after prolonged use of training and time-restricted eating.

Neuroendocrinological and Clinical Aspects of Leptin

Obesity is characterized by an abnormal increase in adipose tissue mass and is regarded as a neurobehavioral as well as a metabolic disorder. Increases in body fat are caused by even slight, long-term discrepancies between energy intake and energy expenditure. It is a chronic condition linked to the metabolic syndrome, a spectrum of risky conditions, such as diabetes, high blood pressure, and heart disease. With a swiftly rising prevalence, obesity has emerged as a significant global health concern. Leptin influences the brain's neuroendocrine and metabolic processes, which is important for maintaining energy homeostasis. White adipose tissue secretes the majority of leptin, and there is a positive correlation between leptin levels in the blood and body fat percentages. The central nervous system is also modulated by leptin levels to modify energy intake and usage. The idea of an obesity cure sparked excitement after it was discovered more than 25 years ago. However, the leptin medication only effectively reduces weight in patients with congenital leptin insufficiency and not in patients with typical obesity who may also have leptin resistance. Recent research has focused on the role of leptin in managing weight reduction and preventing "yo-yo dieting". This review concentrates on the neurological effects of leptin with a focus on therapeutic and diagnostic applications, particularly for childhood obesity.

Synergistic effect rescue animal model from NASH caused by diet-inflammation inducer

Excessive intake of pro-inflammatory fatty acids is related to the development of insulin resistance, impaired oxidative stress enzymes, and lipid disorders, leading to inflammation and development of non-alcoholic steatohepatitis (NASH). Diet and physical exercise are considered to prevent and treat metabolic disorders caused by chronic inflammatory states (responsible for insulin resistance and diabetes type 2) in individuals with obesity and nonalcoholic fatty liver diseases (NAFLD). Our investigation tested the hypothesis that Hass avocado oil, a monounsaturated fatty acid and a source of phytosterol, may improve liver and metabolic parameters without adverse effects when combined with physical exercise. Rats ingested a high-fat diet for seven weeks and were then subjected to more six weeks with a standard diet, Hass avocado-oil ingestion, and swimming. The intervention showed significantly improvements by synergistic effect between Hass avocado-oil and swimming exercise (P < 0.05), including improving adiponectin, leptin, and fasting blood glucose levels, alleviating insulin resistance, reducing serum TNF-α, improving glutathione enzyme levels, and decreasing lipotoxicity in the liver and blood and serum triacylglycerides in blood (P < 0.05). Liver tissue markers of apoptosis and necrosis such as CK-18 filaments and dimethylamine (DMA) were significantly higher in the intervention group (P < 0.05). We were unable to fully confirm our hypothesis. Although the synergistic effects between Hass avocado-oil and the swimming regimen offer a promising chance of recovering liver health by improving 10 health biological markers, we must not ignore the cellular damage due to apoptosis and necrosis in liver cells and DMA. The data on metabolomic profile and avocado-oil-treated livers highlight the need for further investigation.

Reduction of leptin levels during acute exercise is dependent on fasting but not on caloric restriction during chronic exercise: A systematic review and meta-analysis

BACKGROUND

The importance of leptin in controlling body mass has recently gained more attention. Its levels are directly associated with the amount of fat mass, but not necessarily dependent on it. Exercise has great potential in reducing leptin levels, however the response of exercise to this cytokine is still not well understood.

OBJECTIVE

The objective of the review was to analyze the effects of physical exercise on plasma leptin concentration, either acutely (post-exercise/training session) and/or after a training period (short- or long-term), as well as to investigate the existence of possible moderating variables.

METHODS

The studies included in this systematic review were published between 2005 and May 2023. Only peer-reviewed studies, available in English, performed with humans that evaluated the effects of any form of exercise on leptin levels were included. The search was conducted on May 03, 2023, in Embase (Elsevier), MEDLINE via PubMed®, and Web of Science (Core collection). The risk of bias in the included trials was assessed by the Physiotherapy Evidence Database tool, considering 11 questions regarding the methodology of each study with 10 questions being scored. The data (n, mean, and standard deviation) were extracted from included studies to perform random effects meta-analyses using standardized mean difference between the pre- and post-intervention effects.

RESULTS

Twenty-five studies (acute effect: 262 subjects; short- and long-term effect: 377 subjects) were included in this systematic review and meta-analysis. Short- and long-term physical exercise and caloric restriction plus exercise reduce plasma leptin levels, presenting statistically significant differences (p<0.001); as well as acute effect (p = 0.035), however the latter result was influenced by the pre-exercise meal as shown in the subgroup analysis. In this meta-analysis the effect of moderating factors on leptin reduction, not addressed by past reviews, is verified, such as the relationship with caloric restriction, exercise intensity and pre-exercise meal on acute responses.

CONCLUSION

Both acute and chronic exercise reduce leptin levels, yet the acute effect is dependent on the pre-exercise meal. In addition to having a long-term reduction in leptin levels, the minimum amount of weekly exercise to have a significant reduction in plasma leptin is 180 minutes of moderate-intensity exercise and 120 minutes of high-intensity exercise.

Adiponectin receptor 1 could explain the sex differences in molecular basis of cognitive improvements induced by exercise training in type 2 diabetic rats

Adipokines dysregulation, the main reason for cognitive impairments (CI) induced by diabetes, shows a sex-dependent pattern inherently and in response to exercise. This study aimed to compare the attenuating effect of 8-week high intensity-interval training (HIIT) on type 2 diabetes (T2D)-induced CI between male and female rats with a special focus on adiponectin and leptin. 28 male & 28 female Wistar rats with an average age of 8 weeks were randomly assigned into four groups: control (Con), exercise (EX), Diabetes (T2D), and Type 2 diabetes + exercise (T2D + Ex). Rats in EX and T2D + EX groups performed HIIT for eight weeks (80-100% Vmax, 4-10 intervals). T2D was induced by 2 months of a high-fat diet and a single dose of STZ (35 mg/kg) administration. Leptin and adiponectin levels in serum were measured along with hippocampal expression of leptin and adiponectin receptors, AMP-activated protein kinase (AMPK), dephosphorylated glycogen synthase kinase-3 beta (Dep-GSK3β), Tau, and beta-amyloid (Aβ). Homeostasis model assessments (HOMAs) and quantitative insulin-sensitivity check index (QUICKI) indices were calculated. Our results showed that following T2D, serum levels of APN, and hippocampal levels of adiponectin receptor 1 (APNR1) were higher and HOMA-IR was lower in female than male rats (P < 0.05). However, after 8 weeks of HIIT, hippocampal levels of APNR1 and AMPK as well as QUICKI were lower and hippocampal levels of GSK, Tau, and Aβ were higher in females compared to male rats (P < 0.05). While the risk of CI following T2D was more in male than female rats HIIT showed a more ameliorating effect in male animals with APN1 as the main player.

Highlighting the idea of exerkines in the management of cancer patients with cachexia: novel insights and a critical review

BACKGROUND

Exerkines are all peptides, metabolites, and nucleic acids released into the bloodstream during and after physical exercise. Exerkines liberated from skeletal muscle (myokines), the heart (cardiokines), liver (hepatokines), white adipose tissue (adipokines), brown adipose tissue (batokines), and neurons (neurokines) may benefit health and wellbeing. Cancer-related cachexia is a highly prevalent disorder characterized by weight loss with specific skeletal muscle and adipose tissue loss. Many studies have sought to provide exercise strategies for managing cachexia, focusing on musculoskeletal tissue changes. Therefore, understanding the responses of musculoskeletal and other tissue exerkines to acute and chronic exercise may provide novel insight and recommendations for physical training to counteract cancer-related cachexia.

METHODS

For the purpose of conducting this study review, we made efforts to gather relevant studies and thoroughly discuss them to create a comprehensive overview. To achieve this, we conducted searches using appropriate keywords in various databases. Studies that were deemed irrelevant to the current research, not available in English, or lacking full-text access were excluded. Nevertheless, it is important to acknowledge the limited amount of research conducted in this specific field.

RESULTS

In order to obtain a comprehensive understanding of the findings, we prioritized human studies in order to obtain results that closely align with the scope of the present study. However, in instances where human studies were limited or additional analysis was required to draw more robust conclusions, we also incorporated animal studies. Finally, 295 studies, discussed in this review.

CONCLUSION

Our understanding of the underlying physiological mechanisms related to the significance of investigating exerkines in cancer cachexia is currently quite basic. Nonetheless, this demonstrated that resistance and aerobic exercise can contribute to the reduction and control of the disease in individuals with cancer cachexia, as well as in survivors, by inducing changes in exerkines.

Associations between changes of smartphone pedometer-assessed step counts and levels of obesity-related breast cancer biomarkers in non-cancer women: A population-based observational study

While a higher level of physical activity (PA) is inversely associated with a higher breast cancer (BC) risk, the health benefits of daily steps on obesity-related BC biomarkers remain unclear. We aimed to understand the associations of changes in step counts with levels of five obesity-related BC biomarkers during a two-year follow-up. In total, 144 non-cancer women (47.96 ± 5.72) were observed on both 2019 and 2021. A structured questionnaire, daily steps and fasting blood samples were collected before (t0, 2019) and after (t1, 2021). Levels of biomarkers (IGF-binding proteins 3, adiponectin, soluble leptin receptor, C-reactive protein, and resistin) were assayed by ELISA. Participants were divided into persistent low steps, decreasing steps, increasing steps, and persistent high steps. Associations of categories on proposed biomarkers were estimated using linear regression models, with persistent low steps as reference. Associations between time-varying step counts with biomarkers were quantified using mixed linear models. Compared with persistent low steps, increasing steps is associated with a reduction in C-reactive protein level (β=-0.74, 95%CI=-1.23--0.26, P-value = 2.98 × 10-3). An inverse association between time-varying step counts with C-reactive protein level was identified, consistent across different obesity types and baseline step level categories. No association with daily step counts was observed for other proteins.

The Role of Adipokines in Health and Disease

Adipokines are cell-signaling proteins secreted by adipose tissue that has been related to a low-grade state of inflammation and different pathologies. The present review aims to analyze the role of adipokines in health and disease in order to understand the important functions and effects of these cytokines. For this aim, the present review delves into the type of adipocytes and the cytokines produced, as well as their functions; the relations of adipokines in inflammation and different diseases such as cardiovascular, atherosclerosis, mental diseases, metabolic disorders, cancer, and eating behaviors; and finally, the role of microbiota, nutrition, and physical activity in adipokines is discussed. This information would allow for a better understanding of these important cytokines and their effects on body organisms.

Influence of Training and Single Exercise on Leptin Level and Metabolism in Obese Overweight and Normal-Weight Women of Different Age

Leptin is one of the important hormones secreted by adipose tissue. It participates in the regulation of energy processes in the body through central and peripheral mechanisms. The aim of this study was to analyse the anthropological and physical performance changes during 9 month training in women of different age and body mass. The additional aim was the analysis of leptin levels in the fasting stage and after a control exercise. Obese (O), overweight (OW), and normal-weight (N) women participated in the study. Additional subgroups of premenopausal (PRE) (<50 years) and postmenopausal (POST) (50+) women were created for leptin level analysis. The main criterion of the division into subgroups was the age of menopause in the population. The control submaximal test and maximal oxygen uptake (VO_2max) according to Astrand-Rhyming procedures was performed at baseline and after 3, 6, and 9 months. Before each control test, body weight (BM), body mass index (BMI), percentage of adipose tissue (% FAT), and mass (FAT (kg)) were measured. Moreover, before and after each test, leptin level was measured. After 9 months, there was a significant decrease in BM in the O (p < 0.05) and OW (p < 0.05) groups with no significant changes in the N group. There was a decrease in BMI in both the O (p < 0.05) and the OW (p < 0.05) groups, with no changes in the N group. The % FAT reduction was noted only in the O group (p < 0.05). VO_2max increased in each of the measured groups (p < 0.05). The fasting leptin level at 0, 3, 6, and 9 months were the highest in the O group. The fasting leptin level before training was highest in the O group compared to the OW group (p < 0.01) and the N group (p < 0.01). It was also higher in the OW group compared to the N group at baseline (0) (p < 0.01) and after 3 and 6 months (p < 0.01). After 9 months, the leptin concentration decreased by 20.2% in the O group, 40.7% in the OW group, and 33% in the N group. Moreover, the fasting leptin level was higher in the POST subgroup compared to the PRE group in the whole group of women (p < 0.05). After a single exercise, the level of leptin in the whole study group decreased (p < 0.05). This was clearly seen, especially in the POST group. The 9 month training had a reducing effect on the blood leptin concentration in groups O, OW, and N. This may have been a result of weight loss and the percentage of fat in the body, as well as systematically disturbed energy homeostasis.

The Effect of Metabolic Profile on Leptin, Adiponectin, and hs-CRP in Children and Adolescents with Type 1 Diabetes

Adipokines are a superfamily of cell signaling proteins produced by the adipose tissue. This study’s purpose was to reveal the association of adipokines (leptin, adiponectin), hs-CRP, and IL-6 with well-known cardiovascular risk factors (lipid profile, diabetes control, obesity, physical activity) in children and adolescents with T1D. This cross-sectional study included 80 participants (36 boys) with T1D, aged (mean ± SD) 14.8 ± 3.4 years. Body Mass Index (BMI), metabolic profile, and level of physical activity were assessed (using pedometers) for evaluation of their effect on serum leptin, adiponectin, IL-6, and hs-CRP. Leptin levels were associated with BMI (beta = 0.184, p < 0.001), waist to hip ratio (beta = −2.017, p = 0.022), Low Density Lipoprotein-C (LDL-C) (beta = 0.021, p = 0.005), and fat mass (beta = 14.07, p < 0.001). Adiponectin was correlated with waist to height ratio (beta = 0.048, p = 0.006), ΒΜΙ (beta = −0.056, p = 0.005), and muscle mass (beta = −0.013, p = 0.020). Interestingly, hs-CRP was associated with weight (beta = 0.035, p < 0.001), ΒΜI (beta = 0.186, p < 0.001), fat mass (beta = 5.2859, p = 0.004), and muscle mass (beta = 0.027, p = 0.008). Multiple regression analysis of muscle mass unveiled associations with log hs-CRP (beta = −1.237, p = 0.014) and inverse IL−6 (beta = 18.57, p = 0.01). Finally, multiple regression models of fat mass unveiled associations with physical activity (7-day-total-step-count) (beta = −3.90 × 10−7, p = 0.027), Inverse IL-6 (beta = −0.1572, p = 0.009), and squared leptin (beta = 0.0077, p = 0.03). This study reports a positive association of leptin with LDL-C, BMI, fat mass, and hip circumference and a negative association of adiponectin with BMI and muscle mass. Finally, hs-CRP was associated with HbA1c, fat mass, and BMI. We propose that leptin, adiponectin, and hs-CRP could be used as prognostic indicators of cardiovascular risk in children with T1D.

Attenuation of Post-Exercise Energy Intake Following 12 Weeks of Sprint Interval Training in Men and Women with Overweight

An acute bout of sprint interval training (SIT) performed with psychological need-support incorporating autonomy, competence, and relatedness has been shown to attenuate energy intake at the post-exercise meal, but the long-term effects are not known. The aim of this trial was to investigate the effects of 12 weeks of SIT combined with need-support on post-exercise food consumption. Thirty-six physically inactive participants with overweight and obesity (BMI: 29.6 ± 3.8 kg·m−2; V˙O2peak 20.8 ± 4.1 mL·kg−1·min−1) completed three sessions per week of SIT (alternating cycling for 15 s at 170% V˙O2peak and 60 s at 32% V˙O2peak) with need-support or traditional moderate-intensity continuous training (MICT) without need-support (continuous cycling at 60% V˙O2peak). Assessments of appetite, appetite-related hormones, and ad libitum energy intake in response to acute exercise were conducted pre- and post-intervention. Fasting appetite and blood concentrations of active ghrelin, leptin, and insulin did not significantly differ between groups or following the training. Post-exercise energy intake from snacks decreased significantly from pre- (807 ± 550 kJ) to post- SIT (422 ± 468 kJ; p < 0.05) but remained unaltered following MICT. SIT with psychological need-support appears well-tolerated in a physically inactive population with overweight and offers an alternative to traditional exercise prescription where dietary intake is of concern.

Metabolomic and proteomic characterization of sng and pain phenotypes in fibromyalgia

BACKGROUND

Fibromyalgia (FM) is characterized by chronic widespread pain. Its pathophysiological mechanisms remain poorly understood, and effective diagnosis and treatments are lacking. This study aimed to identify significantly changed biosignatures in FM and propose a novel classification for FM based on pain and soreness (sng) symptoms.

METHODS

Urine and serum samples from 30 FM patients and 25 controls underwent metabolomic and proteomic profiling.

RESULTS

Compared with controls, FM patients showed significant differential expression of three metabolites in urine and five metabolites and eight proteins in serum. Of them, DETP, 4-guanidinobutanoic acid, SM(d18:1/18:0), PC(20:1(11Z)/18:0), S100A7, SERPINB3, galectin-7 and LYVE1 were first reported as potential biomarkers for FM. Furthermore, lactate, 2-methylmaleate and cotinine in urine and lactate, SM(d18:1/25:1), SM(d18:1/26:1) and prostaglandin D2 (PGD2) and PCYOX1, ITIH4, PFN1, LRG1, C8G, C8A, CP, CDH5 and DBH in serum could differentiate pain- (PG) and sng-dominant groups (SG). Lactate, 2-methylmaleate, cotinine, PCYOX1, ITIH4, PFN1 and DBH have a higher level in SG. SM(d18:1/25:1), SM(d18:1/26:1), PGD2, LRG1, C8G, C8A, CP and CDH5 in SG are lower than PG. The omics results indicated disordered free radical scavenging, and lipid and amino acid metabolism networks and resulting NF-κB-dependent cytokine generation in FM. Lactate level was altered simultaneously in urine and serum and significantly higher in sng-dominant patients than others.

CONCLUSIONS

In this study, we identified potential biomarkers from FM patients. The selected biomarkers could discriminate sng and pain phenotypes in FM patients. These results could help elucidate the underlying pathological mechanisms for more effective diagnosis and therapy for FM.

Leptin receptor signaling is required for intact hypoglycemic counterregulation: A study in male Zucker rats

Hypoglycemia is a major barrier to clinical management of persons with diabetes. Emerging evidence supports a role for leptin in gating hypoglycemic counterregulation. This work demonstrates that male leptin receptor null, Zucker (fa/fa), rats display severe impairments in hypoglycemic counterregulation. Thus, augmenting leptin levels may have clinical utility for preventing hypoglycemia.

Why exercise has a crucial role in cancer prevention, risk reduction and improved outcomes

INTRODUCTION

Exercise is one of several factors known to lower the risk of developing cancer, as well as improve outcomes in patients already diagnosed. People who exercise after cancer have lower rates of cancer complications, treatment toxicities, relapse and improved survival. This review highlights the supportive data and biochemical processes, which explain these potential benefits.

SOURCES OF DATA

PubMed, Embase, Medline and Cochrane libraries were searched for papers which addressed the effects of exercise and physical activity on cancer for this review. The search terms used were physical activity, exercise and cancer up to February 2021. We also referred to the background research required for international exercise intervention study involving men with prostate cancer (INTERVAL-GAP4) and scrutinized references within the robust papers published on this subject to ensure we did not miss any clinically studies. One hundred and eighty eight papers were included.

AREAS OF AGREEMENT

Exercise programmes mitigate many of the complications and risks associated with cancer, particularly thromboembolism, fatigue, weight gain, arthralgia, cognitive impairment and depression.

AREAS OF CONTROVERSY

Molecular and biomarker changes, resulting from exercise, suggest that exercise elicits beneficial changes in insulin-related pathways, down-regulates inflammation and serum oestrogen levels, and enhances oxidative, immune and cellular repair pathways. Nonetheless, the evidence remains preliminary.

GROWING POINTS

The timing, intensity and challenges of prehabilitation, adjunct and rehabilitation exercise programmes are being increasingly understood but their implementation remains sporadic.

AREAS FOR DEVELOPING RESEARCH

More robust clinical trial data are needed to substantiate a causal effect of exercise on overall and cancer-specific survival. These studies are ongoing. Research evaluating the most cost-efficient ways of incorporating prehabilitation, adjunct and rehabilitation programmes into routine practice would be helpful to funding bodies and health care strategists.

Crossing the Antarctica: Exploring the Effects of Appetite-Regulating Hormones and Indicators of Nutrition Status during a 93-Day Solo-Expedition

Future deep space astronauts must maintain adequate nutrition despite highly stressful, isolated, confined and dangerous environments. The present case-study investigated appetite regulating hormones, nutrition status, and physical and emotional stress in a space analog condition: an explorer conducting a 93-day unsupported solo crossing of Antarctica. Using the dried blood spot (DBS) method, the subject drew samples of his blood on a regular basis during the expedition. The DBSs were later analyzed for the appetite regulating hormones leptin and adiponectin. Energy intake and nutritional status were monitored by analysis of albumin and globulin (including their ratio). Interleukin-6 (IL-6) was also analyzed and used as an energy sensor. The results showed a marked reduction in levels of the appetite-reducing hormone, leptin, and the appetite stimulating hormone, adiponectin, during both extreme physical and psychological strain. Nutrition status showed a variation over the expedition, with below-normal levels during extreme psychological strain and levels abutting the lower bounds of the normal range during a phase dominated by extreme physical hardship. The IL-6 levels varied substantially, with levels above the normal range except during the recovery phase. It was concluded that a daily intake of 5058 to 5931 calories seemed to allow recovery of both appetite and nutritional status between extreme physical and psychological hardship during a long Arctic expedition. Furthermore, IL-6 may be a sensor in the muscle-liver, muscle-fat and muscle-brain crosstalk. These results may help guide nutrition planning for future astronaut crews, mountaineers and others involved in highly demanding missions.

The Positive Relationship between Moderate-to-Vigorous Physical Activity and Bone Mineral Content Is Not Mediated by Free Leptin Index in Prepubertal Children: The PANIC Study

Purpose: Moderate-to-vigorous physical activity (MVPA) positively influences bone mineral content (BMC) in prepubertal children, but it is unknown whether this relationship is partially mediated by free leptin index. The aim of this study was to examine whether the relationship between MVPA and total body less head (TBLH) BMC is mediated or moderated by free leptin index in prepubertal children. Methods: We performed a cross-sectional analysis on 401 children (194 girls) from baseline examinations of the Physical Activity and Nutrition in Childhood Study. We applied the four-way decomposition mediation analysis method to assess whether free leptin index, measured from fasted blood samples, mediated the relationship between accelerometer-measured MVPA and TBLH BMC measured by dual-energy X-ray absorptiometry. Results: MVPA had a positive controlled direct effect on TBLH BMC in girls and boys (β = 0.010 to 0.011, p < 0.05). There was no mediation or interaction between MVPA, free leptin index and TBLH BMC in girls or boys (β = −0.000 to 0.001, p > 0.05). Conclusion: Our study indicates that MVPA positively influences TBLH BMC through pathways not related to free leptin index in predominantly normal-weight prepubertal children, likely primarily through mechanical loading. The relationships between MVPA, free leptin index and TBLH BMC may be influenced by other factors such as pubertal status and adiposity, so it is unknown whether these observations extend to overweight and obese children at different stages of puberty.

Sex-dependent effects of forced exercise in the body composition of adolescent rats

Determining the body composition during adolescence can predict diseases such as obesity, diabetes, and metabolic syndromes later in life; and physical activity became an effective way to restore changes in body composition. However, current available literature assessing the body composition before, during and after adolescence in female and male rodents by in vivo techniques is scarce. Thus, by using computerized tomography, we aimed to define the baseline of the weight and body composition during the adolescence and young adulthood of female and male Sprague-Dawley rats (on P30, P60 and P90) under standard diet. Then, we determined the effect of 18 days of forced exercise on the body weight and composition during the early adolescence (P27-45). The highest percentual increments in weight, body volume and relative adipose contents occurred during the female and male adolescence. Forced running during the early adolescence decreased weight, body volume and relative adipose delta and increment values in males only. The adolescence of rats is a period of drastic body composition changes, where exercise interventions have sex-dependent effects. These results support a model that could open new research windows in the field of adolescent obesity.

Leptin and obesity

An imbalance between calorie intake and energy expenditure produces obesity. It has been a major problem in societies of the developing and developed world. In obesity an excessive amount of fat accumulates in adipose tissue cells as well as in other vital organs like liver, muscles, and pancreas. The adipocytes contain ob genes and express leptin, a 16 kDa protein. In the present communication, we reviewed the molecular basis of the etiopathophysiology of leptin in obesity. Special emphasis has been given to the use of leptin as a drug target for obesity treatment, the role of diet in the modulation of leptin secretion, and reduction of obesity at diminished level of blood leptin induced by physical exercise.

Effects of a single bout of short-duration high-intensity and long-duration low-intensity exercise on insulin resistance and adiponectin/leptin ratio

OBJECTIVES

Moderate-intensity exercise improves insulin sensitivity, which may depend on the intensity, duration, and frequency of exercise. We examined the effects of a single bout of short-duration high-intensity exercise (HIE) and long-duration lowintensity exercise (LIE) on insulin sensitivity and the adiponectin/leptin ratio in individuals with different body mass indices (BMIs) who do not exercise regularly.

METHODS

We enrolled 42 healthy volunteers aged 20-64 years and divided them into two groups based on BMI: BMI <24 kg/m² and BMI ≥27 kg/m². They were randomly assigned to either the short-duration (20 min) HIE (70%-80% heart rate reserve, HRR) or long-duration (60 min) LIE training groups (30%-40% HRR). Glucose, insulin, adiponectin, and leptin levels were assessed before training and at 0, 30, 60, and 120 min after training.

RESULTS

We finally analyzed 27 normal weight and 9 obese individuals. No significant differences were observed in the baseline information of both BMI groups. Homeostatic model assessment for insulin resistance significantly improved for both exercise patterns in the normal weight group and for the HIE pattern in the obese group (P < 0.01), whereas the adiponectin/leptin ratio increased significantly only among normal weight participants with the LIE intervention.

CONCLUSION

Both exercise patterns in BMI <24 kg/m² and BMI ≥27 kg/m² benefit on insulin resistance. Therefore, people can choose the way they can fit to improve insulin resistance both short-duration high-intensity exercise and long-duration low-intensity exercise.

High intensity interval training does not result in short- or long-term dietary compensation in cardiac rehabilitation: Results from the FITR heart study

The aim of this study was to investigate short- and long-term compensatory effects on dietary intake following high intensity interval training (HIIT) compared with usual care moderate intensity continuous training (MICT) during and following a cardiac rehabilitation program. This study investigates secondary outcomes of a clinical trial. Ninety-three participants with coronary artery disease enrolled in a 4-week cardiac rehabilitation program, were randomised to 1) 4x4-minute HIIT; or 2) 40-min of MICT (usual care). Patients were instructed to complete 3 weekly sessions (2 supervised, 1 home-based) for 4-weeks, and 3 weekly home-based sessions thereafter for another 48-weeks. Dietary intake was measured by telephone-based 24-h recall over 2 day at baseline, 4-weeks, 3-months, 6-months, and 12-months. Three-Factor Eating Questionnaire was used to measure dietary behaviour and Leeds Food Preference Questionnaire used to measure food preferences. Appetite was assessed by a visual analogue scale and appetite-regulating hormones. There was no change over the study period or differences between groups for daily energy intake at 4-weeks or 12-months. There were also no group differences for any other measures of dietary intake, fasting hunger or appetite-related hormones, dietary behaviour, or food preferences. These findings suggest that compared to moderate intensity exercise, HIIT does not result in compensatory increases of energy intake or indicators of poor diet quality. This finding appears to be the same for patients with normal weight and obesity. HIIT can therefore be included in cardiac rehabilitation programs as an adjunct or alterative to MICT, without concern for any undesirable dietary compensation.

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.

Vitamin D and selected cytokine concentrations in postmenopausal women in relation to metabolic disorders and physical activity

Obesity and metabolic disturbances constitute significant health problems in elderly women. Due to the multifactorial background of these disorders, assessing the interaction between risk factors remains a significant part of prevention and health promotion. Studies have illustrated a relationship between low physical activity and vitamin D deficiency with obesity and its complications. Furthermore, vitamin D affects the production of adipokines and the inflammatory response in adipose tissue. The aim of our study was to determine the association between selected adipokines, vitamin D concentrations, physical activity (PA), and visceral adiposity index (VAI) in postmenopausal women. The study sample consisted of 318 ethnically homogenous postmenopausal women aged 50-60. Both anthropometric measurements (BMI, WC, WHR) and biochemical measurements (TC, HDL, LDL, TG, AIP, glucose, insulin, IL-6, TNF-α, adiponectin, leptin) were made, and PA by IPAQ were recorded. Body mass index (BMI), waist-to-hip ratio (WHR), HOMA, atherogenic index of plasma (AIP), and VAI were calculated using the standard formulas. We observed a negative correlation between BMI, WC, insulin, HOMA, and PA. We determined that there is a negative association between leptin and vitamin 25(OH)D concentrations (P = 0.007) and a positive association with adiponectin (P = 0.014). The results of the multiple linear regression analysis indicate that vitamin D and HOMA are independent factors that significantly affect leptin and adiponectin levels, contrary to VAI.

Effects of short-term exercise on food intake and the expression of appetite-regulating factors in goldfish

In mammals, growing evidence indicates that exercise affects food intake, metabolism and the expression and blood levels of appetite regulators. In this study, we examined the effects of short-term (30 min, at low and high water flow) exercise on food intake, glucose levels and the expressions of appetite regulators in goldfish hypothalamus (irisin, orexin, CART, leptin), intestine (CCK, PYY, proglucagon/GLP-1), muscle (irisin) and liver (leptin), of brain-derived neurotrophic factor (BDNF) in brain, interleukin-6 (IL6) in muscle and hypothalamus, and major metabolic enzymes, the glycolytic enzyme glucokinase (GCK) and its regulatory protein (GCKR) in liver, the lipolytic enzyme lipoprotein lipase in intestine and muscle, and trypsin in intestine. Fish submitted to high flow exercise had a lower post-exercise food intake compared to control fish but no differences were seen in glucose levels between groups. Exercise induced an increase in hypothalamic expression levels of CART, IL6 and BDNF, but not orexin, irisin, CRF, leptin and NPY. High flow exercise induced an increase in intestine CCK, PYY and GLP-1, and muscle irisin and IL-6 expression levels. Exercise had no effects on expression levels of hepatic leptin or any of the metabolic enzymes examined. Our results suggest that, in goldfish, short-term exercise might decrease feeding in part by affecting the expressions of myokines and peripheral, but not central appetite regulators or metabolic enzyme/hormones.

Biomarkers of insulin action during single soccer sessions before and after a 12-week training period in type 2 diabetes patients on a caloric-restricted diet

BACKGROUND

We investigated the biomarkers of insulin action as well as changes in free fatty acids and lactate concentration after an acute soccer session pre and post training with caloric-restricted diet versus diet alone in type 2 diabetes (T2D) patients.

METHODS

Fifty-one middle-aged (61.1 ± 6.4 years) T2D patients were randomly allocated to the soccer+diet group (SDG) or the diet group (DG). The control group comprised T2D patients observing a caloric-restricted diet who did not receive soccer training. Over 12 weeks, SDG performed 3 × 40 min per week of soccer training.

RESULTS

The first soccer session for SDG induced acute increases in blood lactate (1.4 ± 0.1-6.0 ± 0.7 mmol/l, P < 0.05) and glucagon levels (112.1 ± 6.2-142.9 ± 8.0 pg/ml, P < 0.05), whereas glucose and insulin levels remained unchanged. Moreover, this session showed suppressed insulin levels as well as higher free fatty acids, lactate levels and glucagon/insulin ratio compared to DG (p < 0.05). After 12 weeks, a baseline decrease was observed in glucagon, leptin and lactate levels in SDG and DG (p < 0.05), whereas HOMA-IR, Adipo-IR and glucose levels were lower only in SDG (p < 0.05). At the last soccer training session, the blood lactate response was significantly lower than for the first session (4.0 ± 0.4 vs 6.0 ± 0.7 mmol/l). At 48 h pre intervention, a decrease was observed in leptin levels (p < 0.05), which remained lower post intervention. The positive correlation between leptin and insulin, and the lower levels after training, could be attributed to the improved insulin sensitivity along with the weight loss observed in both groups (~3.4 kg for DG and 3.7 kg for SDG).

CONCLUSION

Acute soccer sessions markedly improved insulin action markers in T2D patients, while the cumulative effects enhanced insulin sensitivity and decreased risk factors associated with cardiovascular disease after 12 weeks of intervention better than caloric-restricted diet.

The Effect of Chronic Exercise Training on Leptin: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Leptin is a hormone associated with satiety, lipid oxidation, energy expenditure, and energy homeostasis. To date, the current body of research examining the effect of chronic exercise training on leptin has yielded inconsistent results.

OBJECTIVE

The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in leptin levels following participation in exercise interventions lasting ≥ 2 weeks.

METHODS

All studies included were peer-reviewed and published in English. To be included, studies randomized human participants to an exercise training group or non-exercise comparison group for an exercise training intervention. Leptin levels were measured at baseline, during, and/or after completion of the exercise training program. Random-effects models were used to aggregate a mean effect size (ES) and 95% confidence intervals (CIs), and identify potential moderators.

RESULTS

Seventy-two randomized controlled trials met the inclusion criteria and resulted in 107 effects (n = 3826). The mean ES of 0.24 (95% CI 0.16-0.32, p < 0.0001) indicated a decrease in leptin following an exercise training program. A decrease in %Fat (β = - 0.07, p < 0.01) was associated with a decrease in leptin after accounting for the type of control group (β = - 0.38, p < 0.0001) used in each study.

CONCLUSION

These results suggest that engaging in chronic exercise training (≥ 2 weeks) is associated with a decrease in leptin levels for individuals regardless of age and sex. However, a greater decrease in leptin occurred with a decreased percentage of body fat.

In middle-aged and old obese patients, training intervention reduces leptin level: A meta-analysis

BACKGROUND

Leptin is one of the major adipokines in obesity that indicates the severity of fat accumulation. It is also an important etiological factor of consequent cardiometabolic and autoimmune disorders. Aging has been demonstrated to aggravate obesity and to induce leptin resistance and hyperleptinemia. Hyperleptinemia, on the other hand, may promote the development of age-related abnormalities. While major weight loss has been demonstrated to ameliorate hyperleptinemia, obese people show a poor tendency to achieve lasting success in this field. The question arises whether training intervention per se is able to reduce the level of this adipokine.

OBJECTIVES

We aimed to review the literature on the effects of training intervention on peripheral leptin level in obesity during aging, in order to evaluate the independent efficacy of this method. In the studies that were included in our analysis, changes of adiponectin levels (when present) were also evaluated.

DATA SOURCES

3481 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 19 articles were suitable for analyses.

STUDY ELIGIBILITY CRITERIA

Empirical research papers were eligible provided that they reported data of middle-aged or older (above 45 years of age) overweight or obese (body mass index above 25) individuals and included physical training intervention or at least fitness status of groups together with corresponding blood leptin values.

STATISTICAL METHODS

We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. To assess publication bias Egger's test was applied. In case of significant publication bias, the Duval and Tweedie's trim and fill algorithm was used.

RESULTS

Training intervention leads to a decrease in leptin level of middle-aged or older, overweight or obese male and female groups, even without major weight loss, indicated by unchanged serum adiponectin levels. Resistance training appears to be more efficient in reducing blood leptin level than aerobic training alone.

CONCLUSIONS

Physical training, especially resistance training successfully reduces hyperleptinemia even without diet or major weight loss.

Exercise-induced biochemical changes and their potential influence on cancer: a scientific review

AIM

To review and discuss the available international literature regarding the indirect and direct biochemical mechanisms that occur after exercise, which could positively, or negatively, influence oncogenic pathways.

METHODS

The PubMed, MEDLINE, Embase and Cochrane libraries were searched for papers up to July 2016 addressing biochemical changes after exercise with a particular reference to cancer. The three authors independently assessed their appropriateness for inclusion in this review based on their scientific quality and relevance.

RESULTS

168 papers were selected and categorised into indirect and direct biochemical pathways. The indirect effects included changes in vitamin D, weight reduction, sunlight exposure and improved mood. The direct effects included insulin-like growth factor, epigenetic effects on gene expression and DNA repair, vasoactive intestinal peptide, oxidative stress and antioxidant pathways, heat shock proteins, testosterone, irisin, immunity, chronic inflammation and prostaglandins, energy metabolism and insulin resistance.

SUMMARY

Exercise is one of several lifestyle factors known to lower the risk of developing cancer and is associated with lower relapse rates and better survival. This review highlights the numerous biochemical processes, which explain these potential anticancer benefits.

Associations of objective physical activity with insulin sensitivity and circulating adipokine profile: the Framingham Heart Study

The purpose of this study was to explore the relation of physical activity (PA) and sedentary time (SED) to insulin sensitivity and adipokines. We assessed PA and SED using Actical accelerometers and insulin resistance (HOMA-IR) in 2109 participants (free of type 1 and 2 diabetes mellitus) from Framingham Generation 3 and Omni 2 cohorts (mean age 46 years, 54% women). Systemic inflammation (C-reactive protein [CRP]) and circulating adipokines were measured 6 years earlier. Steps per day, moderate-to-vigorous PA (MVPA) and SED per wear time (%SED) were predictor variables in multivariable regression analyses, with HOMA-IR, CRP and circulating adipokines as outcome measures. We reported that higher MVPA and more steps per day were associated with lower HOMA-IR, adjusting for %SED (β = -0.036, P = 0.002; β = -0.041, P = 0.005). Steps were inversely associated with CRP, but were directly associated with insulin-like growth factor (IGF)-1 levels (β = -0.111, P = 0.002; β = 3.293, P = 0.007). %SED was positively associated with HOMA-IR (β = 0.033, P < 0.0001), but non-significant after adjusting for MVPA (P = 0.13). %SED was associated with higher ratio of leptin/leptin receptor (sOB-R) and higher adipocyte fatty acid-binding protein (FABP)4 (β = 0.096, P < 0.0001; β = 0.593, P = 0.002). Our findings suggest differential influences of PA vs. SED on metabolic pathways, with PA modulating insulin resistance and inflammation, whereas SED influences FABPs.

Leptin, adiponectin, and ghrelin responses to endurance exercise in different ambient conditions

Excessive positive energy balance is a major factor leading to obesity. The ability to alter the appetite-regulating hormones leptin, adiponectin, and ghrelin may help decrease excessive energy intake. Exercise and exposure to extreme temperatures can independently affect these appetite-regulating hormones.

PURPOSE

To determine the effect of exercising in different environmental conditions on the circulating concentrations of leptin, adiponectin, and ghrelin.

METHODS

Eleven recreationally-trained male participants completed 3 separate 1 h cycling bouts at 60% W_max in hot, cold, and room temperature conditions (33°C, 7°C, 20°C), followed by a 3 h recovery at room temperature. Blood was drawn pre-exercise, post-exercise, and 3 h post-exercise. Hematocrit and hemoglobin were measured to account for change in plasma volume.

RESULTS

Leptin concentrations were lower at post and 3 h post-exercise compared with pre-exercise, with and without correction for plasma volume shifts, regardless of temperature (p < 0.05). Adiponectin was higher post-exercise compared with pre-exercise (p = 0.021) but not 3 h post-exercise (p = 0.084) without correction for plasma volume shifts. However, adiponectin concentrations were not different at any time point when plasma volume shifts were accounted for (p > 0.05). Total ghrelin and acylated ghrelin concentrations were not affected at post and 3 h post-exercise compared with pre-exercise, with and without correcting for plasma volume shifts, regardless of ambient temperature (p > 0.05). No differences in leptin, adiponectin, or ghrelin were found between trials (p > 0.05).

CONCLUSION

Temperature does not affect the circulating concentrations of appetite-regulating hormones during an acute bout of endurance exercise.

Short-Term High-Intensity Interval Training on Body Composition and Blood Glucose in Overweight and Obese Young Women

This study was to determine the effects of five-week high-intensity interval training (HIIT) on cardiorespiratory fitness, body composition, blood glucose, and relevant systemic hormones when compared to moderate-intensity continuous training (MICT) in overweight and obese young women. Methods. Eighteen subjects completed 20 sessions of HIIT or MICT for five weeks. HIIT involved 60 × 8 s cycling at ~90% of peak oxygen consumption ([Formula: see text]) interspersed with 12 s recovery, whereas MICT involved 40-minute continuous cycling at 65% of [Formula: see text]. [Formula: see text], body composition, blood glucose, and fasting serum hormones, including leptin, growth hormone, testosterone, cortisol, and fibroblast growth factor 21, were measured before and after training. Results. Both exercise groups achieved significant improvements in [Formula: see text] (+7.9% in HIIT versus +11.7% in MICT) and peak power output (+13.8% in HIIT versus +21.9% in MICT) despite no training effects on body composition or the relevant systemic hormones. Blood glucose tended to be decreased after the intervention (p = 0.062). The rating of perceived exertion in MICT was higher than that in HIIT (p = 0.042). Conclusion. Compared with MICT, short-term HIIT is more time-efficient and is perceived as being easier for improving cardiorespiratory fitness and fasting blood glucose for overweight and obese young women.

Serum zinc is associated with plasma leptin and Cu-Zn SOD in elite male basketball athletes

This paper investigates the relationship between plasma trace element and plasma leptin, as well as percent fat mass, in 16 male basketball athletes. Blood samples were obtained before intensive training and 24h after intensive training to measure plasma zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iron (Fe), and leptin levels. High-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), triglyceride (TG), total and cholesterol (TC) levels were determined using commercially available kits for humans. Subjects presented similar values in terms of age (21.1±2.2 years old), body mass index (23.9±2.00kg/m(2)), percent body fat (14.40±1.52%), plasma hemoglobin (150.1±9.4g/L), plasma Zn (17.47±1.28μmol/l), plasma Cu (13.42±1.40μmol/L), plasma Ca (2.41±0.14mmol/L), and plasma Mg (0.96±0.02mmol/L). The correlation analysis between degree of plasma leptin and plasma element contents was performed using the SPSS 16.0 software. Plasma Zn correlated positively with plasma leptin (r=0.746, P<0.01), Cu-Zn SOD (r=0.827, P<0.01), and negatively with percent fat mass (r=-0.598, P<0.05) under no-training conditions. Meanwhile, plasma Cu, Ca, Mg, and Fe did not correlate with plasma leptin or percent fat mass (P>0.05). In conclusion, plasma Zn may be involved in the regulation of plasma leptin and may serve as a lipid-mobilizing factor in Chinese men's basketball athletes.

Pilot study on the effects of a 2-week hiking vacation at moderate versus low altitude on plasma parameters of carbohydrate and lipid metabolism in patients with metabolic syndrome

Background

Hypoxic and hypobaric conditions may augment the beneficial influence of training on cardiovascular risk factors. This pilot study aimed to explore for effects of a two-week hiking vacation at moderate versus low altitude on adipokines and parameters of carbohydrate and lipid metabolism in patients with metabolic syndrome.

Methods

Fourteen subjects (mean age: 55.8 years, range: 39 – 69) with metabolic syndrome participated in a 2-week structured training program (3 hours of guided daily hiking 4 times a week, training intensity at 55-65% of individual maximal heart rate; total training time, 24 hours). Participants were divided for residence and training into two groups, one at moderate altitude (1,900 m; n = 8), and the other at low altitude (300 m; n = 6). Anthropometric, cardiovascular and metabolic parameters were measured before and after the training period.

Results

In study participants, training overall reduced circulating levels of total cholesterol (p = 0.024), low-density lipoprotein cholesterol (p = 0.025) and adiponectin (p < 0.001). In the group training at moderate altitude (n = 8), lowering effects on circulating levels were significant not only for total cholesterol, low-density-lipoprotein cholesterol and adiponectin (all, p < 0.05) but also for triglycerides (p = 0.025) and leptin (p = 0.015), whereas in the low altitude group (n = 6), none of the lipid parameters was significantly changed (each p > 0.05). Hiking-induced relative changes of triglyceride levels were positively associated with reductions in leptin levels (p = 0.006). As compared to 300 m altitude, training at 1,900 m showed borderline significant differences in the pre-post mean reduction rates of triglyceride (p = 0.050) and leptin levels (p = 0.093).

Conclusions

Preliminary data on patients with metabolic syndrome suggest that a 2-week hiking vacation at moderate altitude may be more beneficial for adipokines and parameters of lipid metabolism than training at low altitude. In order to draw firm conclusions regarding better corrections of dyslipidemia and metabolic syndrome by physical exercise under mild hypobaric and hypoxic conditions, a sufficiently powered randomized clinical trial appears warranted.

Trial registration

ClinicalTrials.gov ID NCT02013947 (first received November 6, 2013).

Endocrine alterations from concentric vs. eccentric muscle actions: a brief review

Resistance exercise has a positive effect on many tissues, including heart, bone, skeletal muscle, and nervous tissue. Eccentric muscle actions offer a unique and a potentially beneficial form of exercise for maintaining and improving health. During resistance exercise, the effects of gravity, and mechanical properties of the sarcomere and connective tissue in skeletal muscle allow a greater muscle load during an eccentric (lengthening) muscle contraction than a concentric (shortening) muscle contraction. Consequently, older patients, patients with muscle or limb movement limitations or injuries, as well as cancer patients may be able to benefit from isolated eccentric muscle actions. There are specific physiological responses to eccentric muscle contractions. This review will describe the effects of different eccentric muscle contraction protocols on endocrine responses that could have positive effects on different tissues and recommend direction for future research.

Roles of physical activity and cardiorespiratory fitness on sex difference in insulin resistance in late elementary years

PURPOSE

Little is known about the potential role of lifestyle factors in sex differences in insulin resistance in late elementary school children.

METHODS

In this cross-sectional study, we compared sex differences in Tanner scales, body fat, physical activity (PA) and fitness, and insulin resistance markers in elementary school children (boys, n = 69 and girls, n = 81) aged 12-13 years. Body composition was assessed with a standardized protocol. Cardiorespiratory fitness was measured as oxygen consumption during an incremental treadmill exercise. Fasting blood samples were collected for blood chemistry assays including lipids, glucose, insulin and homeostasis model assessment for insulin resistance (HOMA-IR), leptin, and adiponectin. Daily PA was measured with an accelerometer for 7 consecutive days, and they were classified as low-, moderate-, and vigorous-PA. Independent t-tests were used to compare mean differences in the measured variables between boys and girls. There were significant sex differences in Tanner scales, body mass index, percent body fat, and waist circumference (WC).

RESULTS

Girls had significantly higher values in Tanner scales (p < 0.001) and percent body fat (p < 0.001) than boys. Boys had significantly higher values in body mass index (p = 0.019) and waist circumference (p < 0.001) than girls. Boys also had significantly higher values in VO2max (p < 0.001) and low (p < 0.001), moderate (p < 0.001), and vigorous (p < 0.001) PAs. With respect to metabolic risk factors, girls had significantly higher serum levels of triglycerides (p = 0.005), insulin (p < 0.001), and HOMA-IR (p < 0.001) and significantly lower high-density lipoprotein cholesterol (p = 0.015) than boys.

CONCLUSION

In summary, the current findings of the study showed that the increased risk for insulin resistance in girls over boys is associated with higher Tanner scale and percent body fat in conjunction with poor cardiorespiratory fitness and physical inactivity, suggesting that exercise intervention to promote physical activity and fitness is imperative for general health promotion of school children, with a special focus on girls.

Efeito do exercício físico sobre a leptinemia e percentual de gordura de adultos

INTRODUÇÃO/OBJETIVO: O presente estudo se propôs a verificar a influência do exercício físico aeróbio associado aos exercícios de resistência sobre os níveis séricos de leptina e percentual de gordura corporal de adultos com sobrepeso ou obesidade.MÉTODOS: O grupo de estudos foi composto por 15 pessoas, cinco homens e 10 mulheres, com média de idade de 52 anos, com sobrepeso ou obesidade de acordo com critérios da Organização Mundial de Saúde. O programa de exercícios físicos foi realizado três vezes na semana, durante 14 semanas. Era constituído de alongamento, 30 minutos de exercício aeróbio de intensidade moderada e exercícios de resistência muscular localizada. Os dados obtidos foram analisados por meio de estatística descritiva e teste "t" de Student, adotando-se um nível de significância de 5%.RESULTADOS: Os resultados demonstraram redução no peso corpóreo, índice de massa corporal (IMC) e leptinemia em resposta às atividades físicas, porém somente a redução na leptinemia foi significativa (p<0,05).CONCLUSÃO: O protocolo de exercícios adotado foi eficaz na redução dos níveis séricos de leptina em adultos com sobrepeso ou obesidade. Acredita-se que um maior tempo de intervenção com exercícios físicos traga melhores resultados sobre a composição corporal e normalização da leptinemia sérica.

Effect of chronic exercise on appetite control in overweight and obese individuals

PURPOSE

The effect of exercise on body mass is likely to be partially mediated through changes in appetite control. However, no studies have examined the effect of chronic exercise on obestatin and cholecystokinin (CCK) plasma concentrations or the sensitivity to detect differences in preload energy in obese individuals. The objective of this study was to investigate the effects of chronic exercise on 1) fasting and postprandial plasma concentrations of obestatin, CCK, leptin, and glucose insulinotropic peptide (GIP) and 2) the accuracy of energy compensation in response to covert preload manipulation.

METHODS

This study used a 12-wk supervised exercise program in 22 sedentary overweight/obese individuals. Fasting/postprandial plasma concentrations of obestatin, CCK, leptin, and GIP were assessed before and after the intervention. Energy compensation at a 30-min test meal after a high-energy (607 kcal) or a low-energy (246 kcal) preload and for the rest of the day (cumulative energy intake [EI]) was also measured.

RESULTS

There was a significant reduction in the plasma concentration of fasting plasma GIP and both fasting and postprandial leptin concentrations after the exercise intervention (P < 0.05 for all). No significant changes were observed for CCK or obestatin. A significant preload-exercise interaction (P = 0.011) was observed on cumulative EI and energy compensation for the same period (-87% ± 196% vs 68% ± 165%, P = 0.011). Weight loss (3.5 ± 1.4 kg, P < 0.0001) was not correlated with changes in energy compensation.

CONCLUSIONS

This study suggests that exercise improves the accuracy of compensation for previous EI, independent of weight loss. Unexpectedly, and in contrast to GIP and leptin, exercise-induced weight loss had no effect on obestatin or CCK concentrations.

Exercise induced adipokine changes and the metabolic syndrome

The lack of adequate physical activity and obesity created a worldwide pandemic. Obesity is characterized by the deposition of adipose tissue in various parts of the body; it is now evident that adipose tissue also acts as an endocrine organ capable of secreting many cytokines that are though to be involved in the pathophysiology of obesity, insulin resistance, and metabolic syndrome. Adipokines, or adipose tissue-derived proteins, play a pivotal role in this scenario. Increased secretion of proinflammatory adipokines leads to a chronic inflammatory state that is accompanied by insulin resistance and glucose intolerance. Lifestyle change in terms of increased physical activity and exercise is the best nonpharmacological treatment for obesity since these can reduce insulin resistance, counteract the inflammatory state, and improve the lipid profile. There is growing evidence that exercise exerts its beneficial effects partly through alterations in the adipokine profile; that is, exercise increases secretion of anti-inflammatory adipokines and reduces proinflammatory cytokines. In this paper we briefly describe the pathophysiologic role of four important adipokines (adiponectin, leptin, TNF-α, and IL-6) in the metabolic syndrome and review some of the clinical trials that monitored these adipokines as a clinical outcome before and after exercise.

Plasma leptin and vascular endothelial growth factor (VEGF) in normal subjects at high altitude (5050 m)

CONTEXT

High altitude (HA) is a model of severe hypoxia exposure in humans. We hypothesized that nocturnal hypoxemia or acute maximal exercise at HA might affect plasma leptin and VEGF levels.

OBJECTIVES

Plasma leptin, VEGF and other metabolic variables were studied after nocturnal pulse oximetry and after maximal exercise in healthy lowlanders on the 3rd-4th day of stay in Lobuche (5050 m, HA) and after return to sea level (SL).

RESULTS

Leptin was similar at SL or HA in both pre- and post-exercise conditions. Pre-exercise VEGF at HA was lower, and cortisol was higher, than at SL, suggesting that nocturnal intermittent hypoxia associated with periodic breathing at HA might affect these variables.

CONCLUSIONS

Leptin levels appear unaffected at HA, whereas nocturnal hypoxic stress may affect plasma VEGF. Future HA studies should investigate the possible role of nocturnal intermittent hypoxemia on metabolism.

The effects of treadmill exercise on expression of UCP-2 of brown adipose tissue and TNF-α of soleus muscle in obese Zucker rats

Sorts of abnormal state, obesity and inflammation are involved in a number of serious disease occurring and both of them became important research topics among molecular biologists. UCP-2 and TNF-α respectively reflecting obese and inflammatory status have often been used to evaluate the effects of independent variable, such as exercise, on them. Because exercise has shown its potent control on obesity and inflammation, it is necessary to determine if exercise is working via same bioindices. The purpose of this study was to determine the effects of different treadmill exercise intensities on UCP-2 of brown adipose tissue and TNF-α of soleus muscle during 8 weeks in Zucker rat. Zucker rats were divided into four groups (n = 7 in each group): control group, low intensity exercise group, moderate intensity exercise group and high intensity exercise group. Zucker rats of the exercise groups were made to run on a motorized treadmill for 30 minutes once a day during 8 weeks. Rats were sacrificed 24 hours after the last bout of exercise. Blood glucose in Zucker rats were measured by Gluco-Card Ⅱ. Brown adipose tissue were extracted to analyze the level of UCP-2 and TNF-α, respectively. UCP-2 and TNF-α were analyzed using the Western Blotting technique. Statistical techniques for data analysis were repeated measure ANOVA and one way ANOVA to determine the difference between groups, and for post hoc test was Duncan' test. The 5% level of significance was utilized as the critical level for acceptance of hypotheses for the study. The following results were obtained from this study; UCP-2 protein expression of brown adipose tissue in Zucker rats were increased significantly following exercise of the low and moderate intensities compared to those of control group after 8 weeks. It was shown that TNF-α protein expression of soleus muscle in Zucker rats were decreased significantly following exercise of the low and moderate intensities compared to those of control group after 8 weeks. But no significant differences in levels of fasting glucose were shown between groups. The present data suggested that low and moderate intensities treadmill exercise may improve glycometabolism control and fat oxidation by up-regulating UCP-2 expression. In addition, we found low and moderate intensities reduce damages on skeletal muscle by down-regulation the TNF-α in Zucker rats. Thus, the low and moderate intensity exercise are appropriate for anti-obesity and inflammatory effects.