Acute exercise effect on postabsorptive serum leptin

Effects of exercise training on inflammatory and cardiometabolic health markers in overweight and obese adults: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The improvements in inflammation and cardiometabolic health play an important role in the prevention and treatment of obesity. However, the interactions between different exercise training (ET) modalities with inflammatory and cardiometabolic biomarkers are not completely understood. This systematic review and meta-analysis investigated the effects of ET on inflammatory and cardiometabolic health markers in overweight and obese adults.

EVIDENCE ACQUISITION

A systematic search was conducted in PubMed, CINAHL, MEDLINE, Cochrane, Google Scholar, Scopus and Web of Science up to December 15, 2021. Thirty-five studies including 2752 participants were included and analyzed using a random-effects model to estimate weighted mean differences (MD) with 95% confidence intervals (CI).

EVIDENCE SYNTHESIS

The meta-analysis found that ET significantly (P<0.05) increased adiponectin (WMD: 0.72 µg/mL; 95% CI: 0.60 to 0.84; SMD=0.65) and maximal oxygen consumption levels (WMD: 5.26 mL.kg.min; 95% CI: 3.84, 6.69; SMD=1.21). Moreover, ET significantly (P<0.05) reduced fasting insulin (WMD: -2.40 μIU/mL; 95% CI: -3.43 to -1.37; SMD=-0.87), fasting blood glucose (WMD: -5.41 mg/dL; 95% CI: -7.91, -2.91; SMD=-0.66), insulin resistance (WMD: -0.66; 95% CI: -1.08, -0.24; SMD=-0.66) and triglyceride levels (WMD: -10.88 mg/dL; 95% CI: -17.61, -4.15; SMD=-0.91). No significant changes were observed in interleukin-6, tumor necrosis factor-α, leptin, C-reactive protein and cholesterol concentrations. Subgroup analysis by type of training indicated that aerobic and resistance exercise had the most consistent beneficial effects as compared to other modalities.

CONCLUSIONS

Our findings suggest that ET may improve inflammation and cardiometabolic health in overweight and obese adults. Aerobic and resistance training appear to be more beneficial for improving adiponectin, fasting insulin, fasting blood glucose, insulin resistance index and triglyceride levels as compared to other exercise modalities. Further long-term studies are required to confirm and expand on these findings.

Implications of Adipose Tissue Content for Changes in Serum Levels of Exercise-Induced Adipokines: A Quasi-Experimental Study

Human adipocytes release multiple adipokines into the bloodstream during physical activity. This affects many organs and might contribute to the induction of inflammation. In this study, we aimed to assess changes in circulating adipokine levels induced by intense aerobic and anaerobic exercise in individuals with different adipose tissue content. In the quasi-experimental study, 48 male volunteers (aged 21.78 ± 1.98 years) were assigned to groups depending on their body fat content (BF): LBF, low body fat (<8% BF, n = 16); MBF, moderate body fat (8−14% BF, n = 19); and HBF, high body fat (>14% BF, n = 13). The volunteers performed maximal aerobic effort (MAE) and maximal anaerobic effort (MAnE) exercises. Blood samples were collected at five timepoints: before exercise, immediately after, 2 h, 6 h, and 24 h after each exercise. The selected cytokines were analyzed: adiponectin, follistatin-like 1, interleukin 6, leptin, oncostatin M, and resistin. While the participants’ MAnE and MAE performance were similar regardless of BF, the cytokine response of the HBF group was different from that of the others. Six hours after exercise, leptin levels in the HBF group increased by 35%. Further, immediately after MAnE, resistin levels in the HBF group also increased, by approximately 55%. The effect of different BF was not apparent for other cytokines. We conclude that the adipokine exercise response is associated with the amount of adipose tissue and is related to exercise type.

Harnessing the Power of Leptin: The Biochemical Link Connecting Obesity, Diabetes, and Cognitive Decline

In this review, the current understanding of leptin’s role in energy balance, glycemic regulation, and cognitive function is examined, and its involvement in maintaining the homeostatic “harmony” of these physiologies is explored. The effects of exercise on circulating leptin levels are summarized, and the results of clinical application of leptin to metabolic disease and neurologic dysfunction are reviewed. Finally, pre-clinical evidence is presented which suggests that synthetic peptide leptin mimetics may be useful in resolving not only the leptin resistance associated with common obesity and other elements of metabolic syndrome, but also the peripheral insulin resistance characterizing type 2 diabetes mellitus, and the central insulin resistance associated with certain neurologic deficits in humans.

Effects of exercise training and detraining on atheromatous matrix metalloproteinase activity in mice

BACKGROUND AND AIMS

Exercise training (ET) helps treat atherosclerosis. However, many patients stop regular ET for various reasons. The effect of detraining on atherosclerosis is not well studied. We examined the effects of ET vs. short-term detraining on atheromatous matrix-metalloproteinase (MMP) activity in preexisting plaque and circulating cytokines/lipids.

METHODS AND RESULTS

Eighteen-week-old apolipoprotein-E^-/- mice (n = 56) on a Western diet underwent: 1) ET for 6-weeks (ET5+1), 2) ET for 5-weeks and detraining for 1-week (ET5+0), 3) ET for the last 1-week (ET0+1), or 4) no treadmill ET at all for 6-weeks (ET0+0). Atheromatous MMP-activity was visualized using molecular imaging with an MMP-2/9-activatable near-infrared-fluorescent probe. Compared with no ET (ET0+0), regular ET (ET5+1) decreased carotid atheromatous MMP activity, but this protective effect was significantly blunted by short-term detraining (ET5+0). Short-term detraining after longer-term ET showed a reduction in MMP-activity similar to short-term ET (ET0+1). Blood levels of lipids and cytokines paralleled the molecular imaging results: exercise caused higher levels of high-density lipoprotein, adiponectin, and interleukin-10 and lower levels of vascular cell adhesion molecule, monocyte chemoattractant protein-1, interleukin-1β, and low-density lipoprotein. However, this beneficial effect was short-lived, with the ET5+0 group being similar to the ET0+0 group, and the ET0+1 group being similar to the ET5+1 group. The effect of exercise can be modeled with an exponential-decay of the protective factor of about 15%/day.

CONCLUSIONS

Even short-term detraining reduces atheroprotective effects, and tips the balance towards atherosclerosis. This suggests that ET, to be effective, needs to be prolonged and regular, and that detraining should be avoided.

Effect of acute aerobic exercise on arterial stiffness and thyroid-stimulating hormone in subclinical hypothyroidism

Acute exercise has been reported to increase thyroid hormone levels and decrease arterial stiffness in healthy young subjects. However, the effect of acute aerobic exercise on circulating thyroid hormone levels and arterial stiffness in patients with subclinical hypothyroidism remains unclear. The aim of this study was to investigate the effects of acute aerobic exercise on arterial stiffness and thyroid hormone levels, and any relationship between these endpoints, in patients with subclinical hypothyroidism. We studied patients with untreated subclinical hypothyroidism (n = 53, 65 ± 12 years old) compared with euthyroid subjects (n = 55, 64 ± 10 years old). Exercise analysis was performed with a ramp cycle ergometer test. Arterial stiffness (cardio-ankle vascular index, CAVI) was measured at baseline and 5 min after exercise. We collected participant blood samples for serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) measurements before and 5 min after exercise. The CAVI and serum TSH levels significantly decreased after exercise in the subclinical hypothyroidism group (CAVI; 8.1 ± 1.6 vs. 8.5 ± 1.5, p < 0.001, TSH; 6.7 ± 1.4 vs. 7.6 ± 1.2 μIU/ml, p < 0.001) and euthyroid group (CAVI; 7.6 ± 1.0 vs. 8.3 ± 0.9, p < 0.001, TSH; 2.2 ± 1.1 vs. 2.4 ± 1.2 μIU/ml, p = 0.005). The changes in CAVI from baseline compared with after exercise were lower, in absolute values, in the subclinical hypothyroidism group than in the euthyroid group (subclinical hypothyroidism group vs euthyroid group; ΔCAVI: - 0.4 ± 0.6 vs. - 0.7 ± 0.7, p = 0.012). The changes in serum TSH from baseline to after exercise were higher, in absolute values, in the subclinical hypothyroidism group than in the euthyroid group (subclinical hypothyroidism group vs euthyroid group; Δ serum TSH: - 1.3 ± 1.4 vs. - 0.3 ± 0.5, p < 0.001). The changes in CAVI from baseline to after exercise were negatively correlated with changes in TSH (r = - 0.32, p = 0.038) in the subclinical hypothyroidism group. In conclusion, acute aerobic exercise decreased both arterial stiffness and serum TSH levels in patients with subclinical hypothyroidism and euthyroid subjects. While the absolute change in arterial stiffness decreased, the absolute change in serum TSH levels increased in patients with subclinical hypothyroidism compared with euthyroid subjects. These data suggest that subclinical hypothyroidism reduces CAVI during acute aerobic exercise. Further changes in absolute levels of serum TSH in subclinical hypothyroidism may result in reduced CAVI improvement by acute aerobic exercise.

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 Paternal Provisioning Hypothesis: effects of workload and testosterone production on men's musculature

OBJECTIVES

Testosterone supports male reproduction through a broad range of behavioral and physiological effects, including the maintenance of sexually dimorphic muscle used in male-male competition. Although it is often assumed that a persistent relationship exists between men's testosterone production and musculature, most studies either fail to find evidence for such a relationship, or document very weak associations. In nonhuman primates, by contrast, correlations between testosterone and muscle mass are higher. Here, we propose the "Paternal Provisioning Hypothesis," which predicts that men's skeletal muscle is less dependent on the effects of androgens than that of other primates, and more sensitive to the physical demands of men's work. This permits human fathers to downregulate testosterone, which has negative impacts on pair-bonding and parenting effort, but without sacrificing the strength and musculature necessary to provision mates and offspring.

METHODS

We tested predictions of the Paternal Provisioning Hypothesis by assessing parental status, salivary testosterone levels, anthropometry, and strength among 122 men (ages 18-78) at the Mogielica Human Ecology Study Site in rural Poland. We chose this population because men practice subsistence agriculture, regularly engaging in physically demanding labor. Grip and chest strength were assessed using a dynamometer, and upper-body musculature was estimated from arm muscle circumference.

RESULTS

In this population, testosterone showed no association with measures of strength or musculature, and was lower in older men and pair-bonded fathers. Marital and parental status and workload, by contrast, were positive predictors of muscle mass and strength measures.

DISCUSSION

These findings offer support for the Paternal Provisioning Hypothesis.

Plasma leptin and energy expenditure during prolonged, moderate intensity, treadmill exercise

BACKGROUND

Current literature shows conflicting results regarding the possible direct role of exercise on leptin concentrations, mainly because of a non-homogeneous level of energy expenditure (EE) and the lack of standardization of energy balance.

AIM

The aim of the study was to evaluate the effect of exercise duration and its corresponding EE on leptin levels, during prolonged treadmill exercise, in a well-controlled laboratory setting.

MATERIALS AND METHODS

Seven young trained males underwent a 4-h treadmill exercise. The starting intensity was set at 65% of maximal oxygen consumption. At the start of the test and throughout the exercise, venous blood samples were drawn for the assays of leptin, glucose, free fatty acids (FFA), cortisol, epinephrine (E) and norepinephrine (NE). Hourly and total EE was monitored with gas analysis.

RESULTS

Plasma leptin levels decreased from 1.10±0.15 to 0.85±0.26 μg/l (p<0.01) at the end of the exercise, reaching a significant reduction already after the second hour. FFA and cortisol showed a progressive significant increase, while glucose did not significantly change throughout the test. Plasma E and NE significantly increased at all sampling times compared to basal values (48.1±30.3 to 352.3±187.7 pg/ml, p<0.001 and 238.1±118.9 to 1798.7±413.5 pg/ml, p<0.001). The random-effects model for panel data analysis showed negative correlation between leptin, NE and the values of progressive EE (r2=0.745, p<0.05).

CONCLUSIONS

Our data demonstrate that, during a prolonged moderate intensity exercise, leptin decrease is significantly related to the total EE. Further, NE concentrations seem to play an important role in the inhibition of leptin secretion.

Regular exercise modulates obesity factors and body composition in sturdy men

The purpose of this study was to find the change and correlation between obesity factors and body composition according to regular exercise. Thirty-six sturdy men at twenty years old in 'K' university students were participated in this study. The subjects were randomly divided into two groups (n= 18 in each group): control group and regular exercise group. Exercise program composed of three programs: warm-up (10 min), work-out (30-60 min), cool-down (10 min), and categorized by five days per week for eight weeks. Aerobic exercise using a treadmill at 60% of heart rate reserve was performed, and weight training was composed of nine different exercises for the large muscles. Before the performing regular exercise, there was no significant difference between control and regular exercise groups. In the present results, 8 weeks regular exercise significantly decreased leptin, weight, fat mass, % fat, waist to hip ratio (WHR), and body mass index (BMI) more than compared to before performing regular exercise, whereas significantly enhanced lean mass more than compared to before performing regular exercise. Furthermore, regular exercise group reduced leptin, weight, fat mass, % fat, WHR, and BMI compared to control group in the post test. In the correlation of obesity-related factors and body composition, tumor necrosis factor-α (TNF-α) showed correlation with weight, lean mass, and fat mass after performing regular exercise. Here in this study, we suggest that regular exercise is a valuable tool for the improvement of health in the sturdy men, because regular exercise suppresses body fat and obesity-related factors.

Júnior CG, Dias RMR. Efeito do treinamento físico na pressão arterial de adolescentes com obesidade

OBJETIVO: Descrever, por meio de uma revisão sistemática, os efeitos do treinamento físico sobre a pressão arterial em adolescentes com obesidade. FONTES DE DADOS: Recorreu-se à revisão sistemática de ensaios clínicos randomizados que analisaram o efeito do treinamento físico sobre a pressão arterial de adolescentes obesos, publicados em periódicos indexados nas bases de dados PubMed/Medline, Lilacs, SciELO e ISI Web of KnowledgeSM. Foram incluídos os estudos que avaliaram adolescentes publicados até 2010, e que possuíam Grupo Controle. SÍNTESE DOS DADOS: Oito estudos atenderam aos critérios de inclusão. Dois deles utilizaram exercícios de força combinados com aeróbios, enquanto seis empregaram apenas os aeróbios. Cinco estudos utilizaram intervenções complementares, sendo a nutricional a mais frequente. Quatro estudos observaram redução da pressão arterial sistólica no Grupo Exercício comparado ao Controle. Nesses quatro estudos, além da redução da pressão arterial, notou-se diminuição da massa corpórea. Todos aqueles que verificaram redução da pressão arterial utilizaram 12 a 24 semanas de exercícios aeróbios, três a seis sessões semanais, com duração de 50 a 90 minutos e intensidade entre 55 e 75% da frequência cardíaca máxima. CONCLUSÕES: O efeito do treinamento físico na pressão arterial de adolescentes obesos é controverso. A redução da pressão arterial parece ocorrer com programas de treinamento aeróbios que promovam também a redução da massa corpórea.

Efeitos agudos do treinamento concorrente sobre os níveis séricos de leptina e cortisol em adultos jovens sobrepesados

OBJETIVO: Este estudo teve como objetivo analisar os efeitos imediatos do treinamento concorrente sobre a leptina e os níveis de cortisol em adultos jovens com sobrepeso. MÉTODOS: Este estudo utilizou uma metodologia quase-experimental. Foram 20 indivíduos voluntários de ambos os sexos, divididos em um grupo sobrepesado treinamento (GST n = 10) e um grupo sobrepesado controle (n = 10). A coleta de sangue foi realizada com os indivíduos em repouso após jejum de 12 horas. Os níveis de leptina e cortisol foram analisados por radioimunoensaio e ensaio por quimioluminescência chimiluminescence antes e imediatamente após o treinamento. ANOVA two way foi utilizada para análise estatística com nível de significância de p < 0,05. RESULTADOS: Na análise da leptina sérica, observou-se diferença significativa intergrupos (GST x GSC) nos momentos pré-intervenção (p = 0,02) e pós-intervenção (p = 0,01). Na análise intragrupos, não foram observadas alterações significativas. E na análise do cortisol sérico intergrupos (GST x GSC), foi observada uma diferença significativa nos momentos pré-intervenção (p = 0,01) e pós-intervenção (p = 0,01), porém, na análise intragrupos, não houve alterações significativas. CONCLUSÃO: Uma única sessão de treinamento concorrente não é suficiente para promover alterações agudas nos níveis de leptina e cortisol dos jovens adultos sobrepesados voluntários deste estudo.

Effect of food restriction and intense physical training on estrous cyclicity and plasma leptin concentrations in rats

Intense physical training and dietary energy restriction have been associated with consequences such as nutritional amenorrhea. We investigated the effects of intense physical training, food restriction or the combination of both strategies on estrous cyclicity in female rats, and the relationship between leptin ad these effects. Twenty-seven female Wistar rats were distributed into four groups: SF: sedentary, fed ad libitum; SR: sedentary subjected to 50% food restriction (based on the food intake of their fed counterparts); TF: trained (physical training on a motor treadmill with a gradual increase in speed and time), fed ad libitum; TR: trained with 50% food restriction. We analysed estrous cyclicity, plasma leptin and estradiol as well as chemical composition of the carcass, body weight variation, and weight of ovaries and perirenal adipose tissue. Data demonstrate that physical training alone was not responsible for significant modifications in either carcass chemical composition or reproductive function. Food restriction reduced leptin levels in all animals and interrupted the estrous cyclicity in some animals, but only the combination of food restriction and physical training was capable of interrupting the estrous cyclicity in all animals. Leptin was not directly related to estrous cyclicity. From our findings, it may be concluded that there is an additive or synergistic effect of energy intake restriction and energy expenditure by intense physical training on estrous cyclicity. Leptin appears to be one among others factors related to estrous cycle, but it probably acts indirectly.

A carbohydrate-restricted diet during resistance training promotes more favorable changes in body composition and markers of health in obese women with and without insulin resistance

OBJECTIVE

To determine whether sedentary obese women with elevated levels of homeostatic model assessment (HOMA) insulin resistance (ie, > 3.5) experience greater benefits from an exercise + higher-carbohydrate (HC) or carbohydrate-restricted weight loss program than women with lower HOMA levels.

METHODS

221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m(2)) participated in a 10-week supervised exercise and weight loss program. The fitness program involved 30 minutes of circuit-style resistance training 3 days per week. Subjects were prescribed low-fat (30%) isoenergetic diets that consisted of 1200 kcals per day for 1 week (phase 1) and 1600 kcals per day for 9 weeks (phase 2) with HC or higher protein (HP). Fasting blood samples, body composition, anthropometry, resting energy expenditure, and fitness measurements were obtained at 0 and 10 weeks. Subjects were retrospectively stratified into lower (LH) or higher (HH) than 3.5 HOMA groups. Data were analyzed by multivariate analysis of variance with repeated measures and are presented as mean ± standard deviation changes from baseline.

RESULTS

Baseline HOMA levels in the LH group were significantly lower than those in the HH group (LH, 0.6 ± 0.7; HH, 6.3 ± 3.4; P = 0.001). Diet and training significantly decreased body weight (-3.5 ± 3 kg), fat mass (-2.7 ± 3 kg), blood glucose (-3%), total cholesterol (-4.5%), low-density lipoproteins (-5%), triglycerides (-5.9%), systolic blood pressure (-2.6%), and waist circumference (-3.7%), while increasing peak aerobic capacity (7.3%). Subjects in the HP group experienced greater weight loss (-4.4 ± 3.6 kg vs -2.6 ± 2.9 kg), fat loss (-3.4 ± 2.7 kg vs -1.7 ± 2.0 kg), reductions in serum glucose (3% vs 2%), and decreases in serum leptin levels (-30.8% vs -10.8%) than those in the HC group. Participants in the HH (-14.1%) and HP-HH (-21.6%) groups observed the greatest reduction in serum blood glucose.

CONCLUSION

A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. Additionally, obese women who initiated training and dieting with higher HOMA levels experienced greater reductions in blood glucose following an HP diet.

Changes in weight loss, body composition and cardiovascular disease risk after altering macronutrient distributions during a regular exercise program in obese women

Background

This study's purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss.

Methods

One hundred forty-one sedentary, obese women (38.7 ± 8.0 yrs, 163.3 ± 6.9 cm, 93.2 ± 16.5 kg, 35.0 ± 6.2 kg•m^-2, 44.8 ± 4.2% fat) were randomized to either no diet + no exercise control group (CON) a no diet + exercise control (ND), or one of four diet + exercise groups (high-energy diet [HED], very low carbohydrate, high protein diet [VLCHP], low carbohydrate, moderate protein diet [LCMP] and high carbohydrate, low protein [HCLP]) in addition to beginning a 3x•week^-1 supervised resistance training program. After 0, 1, 10 and 14 weeks, all participants completed testing sessions which included anthropometric, body composition, energy expenditure, fasting blood samples, aerobic and muscular fitness assessments. Data were analyzed using repeated measures ANOVA with an alpha of 0.05 with LSD post-hoc analysis when appropriate.

Results

All dieting groups exhibited adequate compliance to their prescribed diet regimen as energy and macronutrient amounts and distributions were close to prescribed amounts. Those groups that followed a diet and exercise program reported significantly greater anthropometric (waist circumference and body mass) and body composition via DXA (fat mass and % fat) changes. Caloric restriction initially reduced energy expenditure, but successfully returned to baseline values after 10 weeks of dieting and exercising. Significant fitness improvements (aerobic capacity and maximal strength) occurred in all exercising groups. No significant changes occurred in lipid panel constituents, but serum insulin and HOMA-IR values decreased in the VLCHP group. Significant reductions in serum leptin occurred in all caloric restriction + exercise groups after 14 weeks, which were unchanged in other non-diet/non-exercise groups.

Conclusions

Overall and over the entire test period, all diet groups which restricted their caloric intake and exercised experienced similar responses to each other. Regular exercise and modest caloric restriction successfully promoted anthropometric and body composition improvements along with various markers of muscular fitness. Significant increases in relative energy expenditure and reductions in circulating leptin were found in response to all exercise and diet groups. Macronutrient distribution may impact circulating levels of insulin and overall ability to improve strength levels in obese women who follow regular exercise.

Nonhomeostatic control of human appetite and physical activity in regulation of energy balance

Ghrelin and leptin, putative controllers of human appetite, have no effect on human meal-to-meal appetite but respond to variations in energy availability. Nonhomeostatic characteristics of appetite and spontaneous activity stem from inhibition by leptin and ghrelin of brain reward circuit that is responsive to energy deficit, but refractory in obesity, and from the operation of a meal-timing circadian clock.

Paradoxical post-exercise responses of acylated ghrelin and leptin during a simulated night shift

Approximately 10% of employees undertake night work, which is a significant predictor of weight gain, possibly because responses to activity and eating are altered at night. It is known that the appetite-related hormone, acylated ghrelin, is suppressed after an acute bout of exercise during the day, but no researcher has explored whether evening exercise alters acylated ghrelin and other appetite-related outcomes during a subsequent night shift. Six healthy men (mean +/- SD: age 30 +/- 8 yrs, body mass index 23.1 +/- 1.1 kg/m(2)) completed two crossover trials (control and exercise) in random order. Participants fasted from 10:00 h, consumed a test meal at 18:00 h, and then cycled at 50% peak oxygen uptake or rested between 19:00-20:00 h. Participants then completed light activities during a simulated night shift which ended at 05:00 h. Two small isocaloric meals were consumed at 22:00 and 02:00 h. Venous blood samples were drawn via cannulation at 1 h intervals between 19:00-05:00 h for the determination of acylated ghrelin, leptin, insulin, glucose, triglyceride, and non-esterified fatty acids concentrations. Perceived hunger and wrist actimetry were also recorded. During the simulated night shift, mean +/- SD acylated ghrelin concentration was 86.5 +/- 40.8 pg/ml following exercise compared with 71.7 +/- 37.7 pg/ml without prior exercise (p = 0.015). Throughout the night shift, leptin concentration was 263 +/- 242 pg/ml following exercise compared with 187 +/- 221 pg/ml without prior exercise (p = 0.017). Mean levels of insulin, triglyceride, non-esterified fatty acids, and wrist actimetry level were also higher during the night shift that followed exercise (p < 0.05). These data indicate that prior exercise increases acylated ghrelin and leptin concentrations during a subsequent simulated night shift. These findings differ from the known effects of exercise on acylated ghrelin and leptin during the day, and therefore have implications for energy balance during night work.

Leptina, hipertensão arterial e obesidade: importância das ações de enfermagem

O objetivo desta revisão sistemática foi o levantamento de tópicos de relevância sobre as implicações da leptina na modulação da pressão arterial e na gênese, prevenção e tratamento da hipertensão arterial associada à obesidade. Considerando o hormônio como um elo comum entre as duas condições patológicas, foram identificadas as ações para a redução da leptinemia, propostas e discutidas na literatura. Constatou-se que a enfermagem carece de produção de conhecimento que subsidie a assistência ao hipertenso obeso com alterações nos níveis séricos de leptina. Foram descritos os sinais e sintomas multifatoriais que se interrelacionam de maneira dinâmica e paradoxal na manifestação do quadro clínico estudado, com ordenação de intervenções eficazes no cuidado a esses clientes.

Plasma leptin, plasma zinc, and plasma copper are associated in elite female and male judo athletes

The purpose of this study was to compare plasma leptin, plasma zinc, and plasma copper levels and their relationship in trained female and male judo athletes (n = 10 women; n = 8 men). Blood samples were obtained 24 h after training to measure plasma zinc, copper, and leptin levels. Subjects presented similar values to age (22 +/- 2 years old), body mass index (24 +/- 1 kg/m(2)), plasma zinc (17.2 +/- 2 micromol/L), copper (12.5 +/- 2 micromol/L), and leptin (5.6 +/- 1.3 microg/L). However, height, total body mass, lean mass, fat mass, and sum of ten-skinfold thickness were higher in male than female. Plasma leptin was associated with sum of ten skinfolds in male (r = 0.91; p < 0.001) and female athletes (r = 0.84; p < 0.003). Plasma zinc was associated with leptin in males (r = 0.82; p < 0.05) while copper was associated with plasma leptin in females (r = 0.66; p < 0.05). Our results suggest that young judo athletes lost sex-related differences in leptin levels. Plasma zinc, plasma copper, and energy homeostasis may be involved in regulation of plasma leptin.

[Leptin: aspects on energetic balance, physical exercise and athletic amenorhea]

The aim of this manuscript was to review the knowledge about leptin, detailing its relationship with energetic intake and physical activity. Leptin is an adipocyte hormone, recognized mainly for its putative role in control of energy expenditure, food intake, body weight and reproductive function. Leptin has still important peripheral actions, including its role on the ovarian tissue. The intracellular signaling mechanisms are recognized in hypothalamus, but in peripheral tissue are not fully understood. The exercise, when practiced by women, if not appropriately planned according to food intake, can modify the leptin release. When energy imbalances induced by exercise and/or deficient food ingestion occurs, low leptin levels are observed, leading to a reduction in GnRH (gonadotropin-release hormone), in LH (luteinizing hormone) and FSH (follicle-stimulating hormone) in pituitary, and consequently a minor release of ovarian estrogens. This process is named hypothalamic amenorrhea, and has repercussions in the woman's health. In this perspective, it is important to emphasize the need to evaluate the energy expenditure from exercise and to formulate adequate alimentary plans to these individuals.

The effect of short-term exercise on plasma leptin levels in patients with anorexia nervosa

Plasma leptin concentrations are markedly reduced in malnourished patients with anorexia nervosa (AN). Whether the long-term underweight and low-fat stores affect the leptin response to exercise remains unknown. We investigated the effect of 45-minute cycle ergometer exercise (2 W kg-1 of lean body mass [LBM]) on plasma leptin, norepinephrine (NE), glycerol, and insulin levels in 10 patients with AN and in 15 healthy age-matched women (C). Plasma leptin levels immediately and 90 minutes after the exercise bout were significantly reduced compared with basal leptin levels in both AN and C groups (P<.05). Compared with the control trial, leptin levels were significantly lower immediately and 90 minutes after exercise in the AN group (P<.05) but not in the C group. Basal and exercise-induced plasma glycerol and NE levels did not differ significantly between the groups. Basal and exercise-induced plasma insulin levels were significantly lower in the AN group compared with the C group (P<.05). In conclusion, we demonstrated that a single bout of low-intensity exercise significantly reduces plasma leptin levels in patients with AN. In healthy women, exercise had no effect on lowering leptin concentrations beyond the diurnal decrease that occurs in the absence of exercise. Neither NE nor insulin are responsible for the different response of leptin to exercise in AN.

Tratamento multidisciplinar reduz o tecido adiposo visceral, leptina, grelina e a prevalência de esteatose hepática não alcoólica (NAFLD) em adolescentes obesos

O objetivo do presente estudo foi avaliar as alterações promovidas, por intervenção multidisciplinar, nas concentrações plasmáticas de grelina e leptina, adiposidade visceral e prevalência de esteatose hepática não alcoólica (NAFLD), em adolescentes obesos. Foram avaliados 28 adolescentes obesos, 16 meninas (IMC 34,58 ± 3,86kg/m²) e 12 meninos (IMC 37,08 ± 3,17kg/m²), com idade entre 15 e 19 anos, quanto à concentração de leptina, grelina, insulina, assim como a adiposidade visceral e o diagnóstico de NAFLD pelo método de ultra-sonografia. Os resultados demonstraram redução significante na concentração circulante de grelina e leptina e na adiposidade visceral (p < 0,01). Houve ainda redução percentual na prevalência de NAFLD, sendo este um resultado relevante, visto que esta doença pode progredir para cirrose, tanto em crianças quanto em adolescentes obesos. Este tipo de tratamento demonstrou ser eficiente na melhora do perfil metabólico e hormonal, contribuindo para o controle da obesidade e suas co-morbidades em adolescentes obesos.

The effect of increased lipid intake on hormonal responses during aerobic exercise in endurance-trained men

In view of the growing health problem associated with obesity, clarification of the regulation of energy homeostasis is important. Peripheral signals, such as ghrelin and leptin, have been shown to influence energy homeostasis. Nutrients and physical exercise, in turn, influence hormone levels. Data on the hormonal response to physical exercise (standardized negative energy balance) after high-fat (HF) or low-fat (LF) diet with identical carbohydrate intake are currently not available. The aim of the study was to investigate whether a short-term dietary intervention with HF and LF affects ghrelin and leptin levels and their modulators, GH, insulin and cortisol, before and during aerobic exercise. Eleven healthy, endurance-trained male athletes (W(max) 365 +/- 29 W) were investigated twice in a randomized crossover design following two types of diet: 1. LF - 0.5 g fat/kg body weight (BW) per day for 2.5 days; 2. HF - 0.5 g fat/kg BW per day for 1 day followed by 3.5 g fat/kg BW per day for 1.5 days. After a standardized carbohydrate snack in the morning, metabolites and hormones (GH, ghrelin, leptin, insulin and cortisol) were measured before and at regular intervals throughout a 3-h aerobic exercise test on a cycloergometer at 50% of W(max). Diet did not significantly affect GH and cortisol concentrations during exercise but resulted in a significant increase in ghrelin and decrease in leptin concentrations after LF compared with HF diet (area under the curve (AUC) ghrelin LF vs HF: P < 0.03; AUC leptin LF vs HF: P < 0.02, Wilcoxon rank test). These data suggest that acute negative energy balance induced by exercise elicits a hormonal response with opposite changes of ghrelin and leptin. In addition, the hormonal response is modulated by the preceding intake of fat.

Adiponectin and stress hormone responses to maximal sculling after volume-extended training season in elite rowers

The purpose of this study was to investigate the resting and short-duration exercise-induced hormone responses of male rowers as a result of 6 months of volume-extended training season. Body composition, maximal aerobic capacity, and on-water 2000-m sculling performance were assessed before and after a 24-week training in elite rowers (n = 11; 193.1 +/- 5.2 cm; 91.6 +/- 5.8 kg; maximum oxygen consumption [VO2max], 6.2 +/- 0.5 L x min(-1)). Six rowers were selected (SEL; 192.0 +/- 6.3 cm; 93.5 +/- 7.1 kg; VO2max, 6.4 +/- 0.4 L x min(-1)) and 5 were not selected (N-SEL; 194.8 +/- 4.1 cm; 89.6 +/- 4.0 kg; VO2max, 6.0 +/- 0.5 L x min(-1)) for the national team. Resting adiponectin did not change as a result of prolonged training. Adiponectin did not change after 2000-m rowing at baseline either. No responses were also observed 24 weeks later in SEL rowers, whereas a significant decrease (P < .05) was observed in N-SEL rowers. At the same time, leptin also decreased after the first 30 minutes of recovery in N-SEL rowers. After the training period, immediate postexercise increases in growth hormone and testosterone were significantly higher in the whole group of rowers. No differences in cortisol responses were observed before and after the training period in SEL and N-SEL rowers. In conclusion, it appears that resting adiponectin does not change as a result of prolonged training. Training may modify adiponectin response to an short-duration exercise depending on the performance level of athletes. Decreased postexercise adiponectin and leptin values in rowers with lower performance capacity may be indicative of the inadequate recovery of these athletes.

Fat as an endocrine organ: influence of exercise

The prevalence of diabetes and obesity continues to increase. It is therefore important to identify the pathophysiology underlying these disorders. An inability of insulin to stimulate glucose uptake, i.e., insulin resistance, appears to be a common link between diabetes and obesity. The identification of various adipocyte-secreted cytokines (adipocytokines) that influence satiety, energy balance, and insulin sensitivity provide a novel target for the treatment of these disorders. Adipocytokines are differentially expressed with obesity and diabetes, making them a strong candidate for linking insulin resistance to these pathological conditions. This review explores the role of adipocytokines in insulin action and examines the effect of exercise training on adipocytokine content.

Cortisol-induced CXCR4 augmentation mobilizes T lymphocytes after acute physical stress

The aim of this study was to elucidate the mechanism responsible for lymphopenia after exercise. Seven young healthy men volunteered for this study. Peripheral blood mononuclear cells (PBMC) were cultured with cortisol and analyzed for C-X-C motif chemokine receptor 4 (CXCR4) expression by flow cytometry. To determine the effects of exercise, subjects performed exhaustive cycling exercise. PBMC were cultured with plasma obtained before and after the cycling exercise. Alternatively, PBMC obtained before and after exercise were cultured without plasma or glucocorticoid to examine whether PBMC were primed in vivo for CXCR4 expression. We analyzed cortisol- or plasma-treated PBMC to determine their ability to migrate through membrane filters in response to stromal cell-derived factor 1α/CXCL12. Cortisol dose- and time-dependently augmented CXCR4 expression on T lymphocytes, with <6 h of treatment sufficient to augment CXCR4 on T lymphocytes. Postexercise plasma also augmented CXCR4 expression. Cortisol or postexercise plasma treatment markedly enhanced migration of T lymphocytes toward CXCL12. Augmentation of CXCR4 on T lymphocytes by cortisol or plasma was effectively blocked by the glucocorticoid receptor antagonist RU-486. Thus exercise-elicited endogenous cortisol effectively augments CXCR4 expression on T lymphocytes, which may account for lymphopenia after exercise.

Leptin responses to antecedent exercise and hypoglycemia in healthy and type 1 diabetes mellitus men and women

These studies examined the effects of hypoglycemia or exercise on leptin levels in 47 (23 women, 24 men) healthy (age 26+/-2 years, body mass index 23+/-0.5 kg.m(-2)) and type 1 diabetes mellitus (T1DM) subjects (age 29+/-2 years, body mass index 27+/-2 kg.m(-2)). In Study 1, healthy and T1DM subjects were exposed to morning and afternoon 120-min hyperinsulinemic hypoglycemic ( approximately 50 mg/dl) or euglycemic ( approximately 90 mg/dl) clamps. In Study 2, healthy subjects were studied during morning and afternoon 90-min exercise bouts at 50% VO(2max). In Study 1, basal levels of leptin were significantly greater in T1DM vs. the healthy subjects (13.8+/-3 vs. 5.4+/-1 ng/dl; P<.05). However, during the last 30 min of morning hypoglycemia, plasma leptin levels significantly decreased from 5.4+/-1 to 4.0+/-1 ng/dl (P<.05) and remained low during afternoon hypoglycemia (4.3+/-1 ng/dl) in healthy but not T1DM subjects. In Study 2, plasma leptin levels did not significantly change during exercise the bout in healthy men, but significantly decreased 3 h after morning exercise, and continued to decrease during afternoon exercise in healthy women (P<.0001). Thus, plasma leptin levels decrease in response to hypoglycemia in healthy but not T1DM subjects. However, T1DM patients do have increased basal leptin levels compared to healthy man. Lastly, there is a marked sexual dimorphism in plasma leptin responses to repeated episodes of exercise.

Plasma leptin and exercise: recent findings

It is established that plasma leptin is associated with satiety and that leptin stimulates lipid metabolism, and increases energy expenditure. These effects implicate leptin as a major regulator of energy homeostasis, which may serve to limit excess energy storage. As plasma leptin concentrations are tightly coupled with fat mass in humans, decreases in adipose mass with weight loss coincide with decreased concentrations of circulating leptin. However, due to many confounding factors, the effects of exercise on circulating leptin are less clear. The data from investigations examining single exercise bouts suggest that serum leptin concentrations are unaltered by short duration (41 minutes or less), non-exhaustive exercise, but may be affected by short duration, exhaustive exercise. More convincingly, studies investigating long duration exercise bouts indicate that serum leptin concentrations are reduced with exercise durations ranging from one to multiple hours. These findings raise speculation that exercise-associated reductions in leptin may be due to alterations in nutrient availability or nutrient flux at the level of the adipocytes, the primary site of leptin production and secretion. Thus, one purpose of this review is to discuss the effects of exercise on circulating leptin concentrations with special emphasis on studies that have examined single exercise bouts that are associated with high levels of energy expenditure and energy deficit. In addition, a 'nutrient sensing pathway' (the hexosamine biosynthetic pathway), which regulates leptin gene expression, will be discussed as a possible mechanism by which exercise-induced energy deficit may modulate serum leptin concentrations.

Leptin: metabolic control and regulation

Leptin, a protein released from adipose tissue, is being recognized to play an integral role in endocrine regulation of metabolism. While it is clearly evident that leptin is decreased during caloric restriction, the response of leptin to other types of stress has been plagued by conflicting data. With hypoglycemia stress, the literature may conflict because experimentally hypoglycemia is induced with infusion of insulin, an endocrine factor that can increase leptin levels. With exercise, leptin's response may depend on duration and intensity of exercise. While it has been clearly shown that the sympathetic nervous system (SNS) inhibits leptin secretion in a variety of experimental modes, the hypothalamic-pituitary-adrenal (HPA) axis may stimulate leptin secretion. This creates a paradox of leptin regulation during stress since both systems are activated with stress. If the SNS inhibition overrides the HPA axis' activation of leptin secretion, leptin's role during stress may be to allow a shifting of fuel consumption towards carbohydrate utilization. In type 1 diabetes mellitus, autonomic dysfunction may prevent the fall in leptin during stress. Although obesity is associated with type 2 diabetes mellitus, patients may have decreased leptin levels, especially when glucose is poorly controlled. This may contribute to further obesity and worsening of the disease. The purpose of this review to is critically analyze the literature regarding the impact of different types of stress on leptin secretion, the function of leptin during stress, and the role of leptin in the pathophysiology of diabetes.

Leptin and exercise

Short-term exercise (<60 min) studies suggest that leptin concentrations are not acutely affected in healthy males and females. Most reports of reductions in serum leptin may be attributed to circadian rhythms or hemoconcentration. For long-term (> or =60 min) exercise, a reduction in leptin concentrations reported from 1 to 3 hr of running or cycling has been attributed to diurnal reduction in circulating leptin, independent of exercise. Exercise that produces a sufficient energy imbalance (kilocalorie intake versus kilocalorie expenditure) suppresses 24-hr mean and amplitude of the diurnal rhythm of leptin in women. Suppression of leptin concentrations may be counterbalanced by feeding and may explain consistent reports of reductions in leptin concentrations following extreme bouts of exercise such as marathons or ultramarathons. In addition, leptin concentrations are reduced 48 hr after long-term aerobic exercise and long-term resistance exercise is associated with delayed leptin reduction 9 hr postexercise. Training studies have documented that short-term exercise training (< or =12 weeks) does not affect leptin levels, with the exception of patients with type 2 diabetes. Exercise training protocols that result in reduced fat mass will lower leptin concentrations, thus, most investigators have reported leptin concentrations after accounting for fat loss. There are disparate findings concerning long-term (>12 weeks) training studies, with a number of studies finding no effect of training on leptin concentrations other than effects induced by fat loss, and other studies finding reductions in leptin concentrations after accounting for fat loss. Exercise training-induced reductions in leptin levels have been attributed to alterations in energy balance, improvements in insulin sensitivity, alterations in lipid metabolism, and unknown factors. Hormone replacement does not seem to affect leptin adaptations to training. Patients with type 2 diabetes show delayed effects of short-term resistance exercise on leptin concentrations, reduced leptin levels with long-term training, and appear to be more sensitive to training-induced leptin adaptations than other populations.