Effects Of Voluntary Exercise Research Articles

Effects of voluntary exercise on muscle structure and function in cerebral palsy.

Linked Article: https://onlinelibrary.wiley.com/doi/10.1111/dmcn.15173

The effect of voluntary exercise on light cycle stress-induced metabolic resistance.

Disruption of circadian genes affects metabolic homeostasis. Regular exercise programs prevent metabolic dysfunction and alter circadian gene expression In this study, we investigated whether exercise affects light stress-induced circadian rhythm derangement and metabolic resistance. A circadian rhythm derangement mouse model was designed by extending the light exposure by two hours (14 L/10 D) for three weeks. Nine-weekold male mice were single-caged and divided into four groups: sedentary groups with or without light stress, and voluntary wheel-trained groups with or without light stress. In addition, differentiated myotubes were cultured in the presence of dexamethasone with or without 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR). The comprehensive laboratory animal monitoring system was used to analyze the metabolic changes in mice. Moreover, reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the mRNA expression levels of circadian genes in animal and cell culture models. Three weeks of light stress reduced the running distance and increased the weight of mice. In addition, VO2 consumption and heat production were increased during the night cycle under non-stress conditions but not under stress conditions. PCR analysis revealed that exercise and stress altered the expression levels of circadian genes in the hypothalamus and quadriceps muscles. mRNA expression levels of period circadian regulator 1 were downregulated in the quadriceps muscles of the stressed sedentary group compared to that in muscles of the non-stressed sedentary group. Furthermore, differentiated myotube cells cultured in the presence of dexamethasone, with or without AICAR, showed distinct oscillation patterns at various time points. Our study demonstrates that exercise partially prevents metabolic disruption by regulating the circadian gene expression in skeletal muscles.

Effects of Voluntary Physical Exercise on the Neurovascular Unit in a Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide. Histopathologically, AD presents two pathognomonic hallmarks: (1) neurofibrillary tangles, characterized by intracellular deposits of hyperphosphorylated tau protein, and (2) extracellular amyloid deposits (amyloid plaques) in the brain vasculature (cerebral amyloid angiopathy; CAA). It has been proposed that vascular amyloid deposits could trigger neurovascular unit (NVU) dysfunction in AD. The NVU is composed primarily of astrocytic feet, endothelial cells, pericytes, and basement membrane. Although physical exercise is hypothesized to have beneficial effects against AD, it is unknown whether its positive effects extend to ameliorating CAA and improving the physiology of the NVU. We used the triple transgenic animal model for AD (3xTg-AD) at 13 months old and analyzed through behavioral and histological assays, the effect of voluntary physical exercise on cognitive functions, amyloid angiopathy, and the NVU. Our results show that 3xTg-AD mice develop vascular amyloid deposits which correlate with cognitive deficits and NVU alteration. Interestingly, the physical exercise regimen decreases amyloid angiopathy and correlates with an improvement in cognitive function as well as in the underlying integrity of the NVU components. Physical exercise could represent a key therapeutic approach in cerebral amyloid angiopathy and NVU stability in AD patients.

The effects of voluntary exercise on histological and stereological changes of sciatic nerve, nitric oxide levels, and peripheral neuropathy caused by high-fat diet-induced type 2 diabetes in male rats

This research was conducted to investigate the possible beneficial impacts of voluntary exercise on sciatic tissue, nitric oxide levels, stereological changes, and peripheral neuropathy caused by "high-fat-diet (HFD)"-induced "type 2 diabetes mellitus (T2DM)" in male rats. Rats were put into four experimental groups at random: "healthy control (C), voluntary exercise (VE), diabetic (D), and diabetic rats treated by voluntary exercise (VED)"; each group contain eight animals. Animals in VE and VED groups performed "voluntary exercise (VE)" for ten weeks. Animals in D and VED groups became diabetic after receiving a HFD for four weeks and an intraperitoneal injection (IP) of "streptozotocin (STZ)" (35 mg/kg). In order to evaluate mechanical and thermal algesia, hot plate, tail withdrawal, and von Frey tests were carried out. At the end of this study, serum NOx levels were assessed, and histological and stereological analyses were conducted. Mechanical nociceptive thresholds indicated considerable reduction (p < 0.001) which was followed by a remarkable enhance (p < 0.001) in thermal nociceptive threshold of D group. Tissue changes were also seen in sciatic nerve of D group. Voluntary exercise modified thermal and mechanical sensitivity in diabetic rats. It also improved the damaged sciatic nerve in diabetic animals.

Breast muscle white striping and serum corticosterone reduced in broilers exposed to laser environmental enrichment

Genetic selection for breast yields and fewer days to market has inadvertent effects on broiler meat quality. Woody breast (WB) and white striping (WS) are pectoralis major myopathies prevalent in commercial broilers. Effects of voluntary exercise on these disorders, specifically, are unknown. A second-generation laser enrichment device shown to induce activity in Ross 308 and 708 birds was implemented using 1,360 Ross 708 broilers randomly assigned to laser enrichment or control for 49 d. Laser-enriched birds were exposed to 6-min laser periods 4 times daily. Seventy focal birds were gait and contact dermatitis scored weekly. Blood was collected wk 5 to 7 from 56 broilers for serum corticosterone, myoglobin, and troponin. Seventy broilers were sampled for breast muscle width, fillet dimensions, and WB and WS at wk 6 and 7. One and 2-day postmortem, fillet compression force and water-holding capacity were measured. Serum corticosterone was reduced by up to 21% in laser-enriched birds wk 5 to 7 (P < 0.01). Serum myoglobin was increased in laser-enriched broilers by 5% on wk 5 (P < 0.01) but increased in control birds wk 6 to 7 by up to 13% (P < 0.01). Serum troponin was reduced in laser-enriched broilers by 9% at wk 5 (P < 0.01). Laser exposure increased breast width and fillet weight at d 42 by 1.08 cm (P < 0.05) and 30 g (P < 0.05). At d 49, fillet height was increased 0.42 cm in laser-enriched birds (P < 0.05). Laser enrichment reduced severe WS incidence at d 42 by 24% (P < 0.05) and on d 49 by 15% (P < 0.10). Severe WB score was numerically reduced by 11% in laser enrichment on d 42 and 18% on d 49 (P > 0.05). Water-holding capacity was improved in laser-enriched breasts (P < 0.01) and expression of myostatin and insulin-like growth factor 2 were increased on d 49 (P ≤ 0.01. Laser enrichment reduced markers of stress and muscle damage while improving breast muscle quality and is therefore a potential effective enrichment for commercial broilers.

Effects of voluntary exercise and administration of renin angiotensin inhibitor on cardiac function in inherited dilated cardiomyopathy model.

Dilated cardiomyopathy (DCM) is one of major causes of heart failure (HF) especially in Asia. Although exercise is regarded as one of therapies for HF, the effects of exercise on patients with DCM have not been established. A knock-in mouse model of human inherited DCM, TNNT2 ΔK210, shows similar characteristics to DCM patients. We have showed that one of angiotensin receptor blockers (ARB) is effective on cardiac function and electrical remodeling. We also have found that voluntary exercise improves cardiac function in homozygote model mice (DCM mice). In this study, we examined combination therapy of ARB and exersise in DCM mice. The DCM mice showed enlarged heart and frequent sudden death with t1/2 of ∼70 days. Male DCM mice were divided into 4 groups based on the administration of ARB and voluntary exercise: without drug or exercise (CON), oral administration of ARB (ARB), daily exercise (EXE), and combined ARB and exercise (COMB). The EXE and COMB groups started wheel running at 1 month of age. Cardiac function was measured with echocardiography and electrocardiogram at 2.5 months of age. After sacrifice, weights of body, heart, lung, and lower extremity muscles were measured. Gene expressions of HF- and arrhythmia-related genes in myocardium were quantified by qPCR analysis. There was no significant difference in driving performance between EXE and COMB (EXE: 7.0 ± 1.6 km/day (n = 8), COMB: 6.3 ± 2.2 km/day (n = 7)). On echocardiography, the ejection fraction was significantly improved in only COMB (CON: 21.7 ± 6.1% (n = 6), ARB: 26.9 ± 5.1% (n = 6), EXE: 27.2 ± 4.5% (n = 5), COMB: 31.9 ± 3.6% (n = 6)). On the other hand, the heart weight/body weight ratio decreased in the ARB and the COMB groups. Our results suggest that the combination of ARBs and exercise may have a greater effect on cardiac function in DCM mice.

Effects of voluntary exercise on muscle structure and function in cerebral palsy.

Skeletal muscles are required for functional movement and force production. While it is clear that cerebral palsy (CP) results in loss of muscle strength and bodily function, and that much of this loss is caused by injury to the central nervous system, muscle is a very plastic tissue that is also dramatically affected. In many studies, it is assumed that voluntary exercise will cause the muscle to respond in the same way that typically developing muscle does, but there are scarce data demonstrating that this is true. The purpose of this review is to briefly describe muscle architectural adaptation to various forms of exercise with specific reference to voluntary exercise performed in children with CP. Exercise itself is not generic but can vary by intensity, duration, and the exact nature of the muscle length change and velocity imposed during the exercise. Our goal is to stimulate discussion in this area by pointing out salient experimental variables and, ultimately, to improve activity and participation in children with CP.

Effects of voluntary exercise on the expression of browning markers in visceral and subcutaneous fat tissue of normotensive and spontaneously hypertensive rats

High physical activity is important to optimize the function of adipose tissue. Dysfunctional adipose tissue contributes to the development of metabolic stress, chronic inflammation, and hypertension. To improve our current understanding of the interaction between physical exercise and adipose tissue, we analyzed the effect of 10 months voluntary running wheel activity of rats on uncoupling protein (UCP) 1 negative white adipose tissue (visceral and subcutaneous adipose tissue, VWAT and SWAT). Analysis was performed via RT-PCR and immunoblot from adipose tissues depicted from adult normotensive and spontaneously hypertensive female rats. UCP1 negative VWAT differed from UCP1 positive WAT and brown adipose tissue (BAT) from interscapular fat depots, by lacking the expression of UCP1 and low expression of Cidea, a transcriptional co-activator of UCP1. High physical activity affected the expression of five genes in SWAT (Visfatin (up), RBP5, adiponectin, Cidea, and Nrg4 (all down)) but only one gene (Visfatin, up) in VWAT. Furthermore, the expression of these genes is differentially regulated in VWAT and SWAT of normotensive and spontaneously hypertensive rats (SHR) under sedentary conditions (UCP2) and exercise (Visfatin, Cidea, Nrg4). Keeping the animals after 6 months of voluntary exercise under observation for an additional period of 4 months without running wheels, Visfatin, Cidea, and Nrg4 were stronger expressed in VWAT of SHRs than in sedentary control rats. In summary, our study shows that SWAT is more responsible to exercise than VWAT.

Associations of Voluntary Exercise and Screen Time during the First Wave of COVID-19 Restrictions in Japan with Subsequent Grip Strength among University Students: J-Fit+ Study

This study aimed to examine the combined effect of voluntary exercise and screen time during the first wave of the coronavirus disease 2019 (COVID-19) restrictions on subsequent grip strength among health and sports science students in Japan. The participants performed grip strength tests and had their weight assessed on 21 October 2020. Furthermore, they completed an online survey between 21 October and 28 October 2020, which included participants’ current age, height, voluntary exercise, and screen time during the first wave of the COVID-19 pandemic (April and May 2020). In total, 380 participants provided complete data (mean age ± standard deviation [SD]: 18.8 ± 0.6 years; 233 males). Our results revealed that 87.6% of male students and 84.4% of female students performed voluntary exercise &gt;1 day/week during the first wave of the pandemic. Moreover, 21.5% of male students and 23.1% of female students had &gt;8 h/day of screen time. A trend toward greater grip strength was observed for both male and female students with high voluntary exercise and low screen time. In particular, grip strength (p &lt; 0.05) was significantly greater in male students with high voluntary exercise and low screen time than those with low voluntary exercise and high screen time. In conclusion, this study revealed that during the first wave of COVID-19 restrictions, a combination of high voluntary exercise and low screen time positively affected the subsequent grip strength of health and sports science students.

Effect of voluntary exercise upon the metabolic syndrome and gut microbiome composition in mice.

The metabolic syndrome is a cluster of conditions that increase an individual's risk of developing diseases. Being physically active throughout life is known to reduce the prevalence and onset of some aspects of the metabolic syndrome. Furthermore, previous studies have demonstrated that an individual's gut microbiome composition has a large influence on several aspects of the metabolic syndrome. However, the mechanism(s) by which physical activity may improve metabolic health are not well understood. We sought to determine if endurance exercise is sufficient to prevent or ameliorate the development of the metabolic syndrome and its associated diseases. We also analyzed the impact of physical activity under metabolic syndrome progression upon the gut microbiome composition. Utilizing whole‐body low‐density lipoprotein receptor (LDLR) knockout mice on a “Western Diet,” we show that long‐term exercise acts favorably upon glucose tolerance, adiposity, and liver lipids. Exercise increased mitochondrial abundance in skeletal muscle but did not reduce liver fibrosis, aortic lesion area, or plasma lipids. Lastly, we observed several changes in gut bacteria and their novel associations with metabolic parameters of clinical importance. Altogether, our results indicate that exercise can ameliorate some aspects of the metabolic syndrome progression and alter the gut microbiome composition.

Coping with Exercise Induced Spatial Memory Improvement in Morphine Dependent Rats by Inhibiting Brain Derived Neurotrophic Factor (BDNF)

Background: Addiction as a chronic disorder that requires long treatment. One way to treating this chronic disease is exercise. Chronic exposure to opiates impairs spatial learning and memory. Given the well-known beneficial effects of voluntary exercise on cognitive functions, we investigated whether voluntary exercise would ameliorate the cognitive deficits that are induced by morphine dependence. If an effect of exercise was observed, we aimed to investigate the possible role of hippocampal brain-derived neurotropic factor (BDNF) in the exercise-induced enhancement of learning and memory in morphine-dependent rats.&#x0D; Methods: The rats were injected with bi-daily doses (10 mg/kg, at 12 hr. intervals) of morphine over a period of 10 days of voluntary exercise. Following these injections, a water maze task was performed twice a day for 5 consecutive days, followed by a probe trial 2 days later. A specific BDNF inhibitor (TrkB-IgG chimera) was used to block the hippocampal BDNF action during the 10 days of voluntary exercise.&#x0D; Results: The voluntary exercise diminished the severity of the rats’ dependency on morphine. A blockade of the BDNF action blunted the exercise-induced improvement of spatial memory, hippocampal neuron counting and BDNF protein levels in the dependent rats. Our results indicate that voluntary exercise could be increase the expression of LTP by lowering the induction threshold for LTP in the DG of morphine-dependent rats.&#x0D; Conclusion: Thus, voluntary exercise might be considered as a potential method to ameliorate some of the deleterious behavioral consequences of the abuse of morphine and other opiates.

Protective Effects of Voluntary Exercise on Hepatic Fat Accumulation Induced by Dietary Restriction in Zucker Fatty Rats.

Weight control based on dietary restriction (DR) alone can cause lipid metabolic failure and progression to fatty liver. This study aimed to investigate the effect of exercise on preventing DR-induced hepatic fat accumulation in Zucker fatty (ZF) rats by focusing on the relationship between adipose tissue lipolysis and hepatic fat uptake. Six-week-old male ZF rats were randomly assigned to obese, DR, or DR with exercise (DR + Ex) groups. The DR and DR + Ex groups were fed a restricted diet, with the latter also undergoing voluntary exercise. After 6 weeks, hepatic fat accumulation was observed in the DR group, whereas intrahepatic fat was markedly reduced in the DR + Ex group. Compared with the obese (Ob) group, the DR group exhibited 2.09-fold expression of hepatic fatty acid translocase (FAT)/CD36 proteins (p < 0.01) and 0.14-fold expression of hepatic fatty acid-binding protein (FABP)1 (p < 0.01). There were no significant differences between the DR + Ex group and the Ob group. FAT/CD36 and hepatic triglyceride (TG) expression levels were strongly positively correlated (r = 0.81, p < 0.001), whereas there was a strong negative correlation between FABP1 and hepatic TG expression levels (r = −0.65, p < 0.001). Our results suggest that hepatic fat accumulation induced by DR in ZF rats might be prevented through exercise-induced modifications in FAT/CD36 and FABP1 expression.

Effect of voluntary exercise after cerebral ischemia on functional recovery and the peri-infarct cortex

Effect of voluntary exercise after cerebral ischemia on functional recovery and the peri-infarct cortex

Analysis of Activity-Dependent Energy Metabolism in Mice Reveals Regulation of Mitochondrial Fission and Fusion mRNA by Voluntary Physical Exercise in Subcutaneous Fat from Male Marathon Mice (DUhTP).

Physical inactivity is considered as one of the main causes of obesity in modern civilizations, and it has been demonstrated that resistance training programs can be used to reduce fat mass. The effects of voluntary exercise on energy metabolism are less clear in adipose tissue. Therefore, the effects of three different voluntary exercise programs on the control of energy metabolism in subcutaneous fat were tested in two different mouse lines. In a cross-over study design, male mice were kept for three or six weeks in the presence or absence of running wheels. For the experiment, mice with increased running capacity (DUhTP) were used and compared to controls (DUC). Body and organ weight, feed intake, and voluntary running wheel activity were recorded. In subcutaneous fat, gene expression of browning markers and mitochondrial energy metabolism were analyzed. Exercise increased heart weight in control mice (p < 0.05) but significantly decreased subcutaneous, epididymal, perinephric, and brown fat mass in both genetic groups (p < 0.05). Gene expression analysis revealed higher expression of browning markers and individual complex subunits present in the electron transport chain in subcutaneous fat of DUhTP mice compared to controls (DUC; p < 0.01), independent of physical activity. While in control mice, voluntary exercise had no effect on markers of mitochondrial fission or fusion, in DUhTP mice, reduced mitochondrial DNA, transcription factor Nrf1, fission- (Dnm1), and fusion-relevant transcripts (Mfn1 and 2) were observed in response to voluntary physical activity (p < 0.05). Our findings indicate that the superior running abilities in DUhTP mice, on one hand, are connected to elevated expression of genetic markers for browning and oxidative phosphorylation in subcutaneous fat. In subcutaneous fat from DUhTP but not in unselected control mice, we further demonstrate reduced expression of genes for mitochondrial fission and fusion in response to voluntary physical activity.

A model of negative emotional contagion between male-female rat dyads: Effects of voluntary exercise on stress-induced behavior and BDNF-TrkB signaling

Emotional contagion refers to the sharing of emotional states between individuals and can cause depressive behaviors in healthy persons who live with depressed individuals. Negative emotional contagion has been observed in animal models, but the vast majority of studies are short-term and bear little resemblance to long-term human relationships. Thus, the first aim of this study was to establish an animal model of stress-induced negative emotional contagion that develops across time and between pairs. To accomplish this, we tested the hypothesis that sedentary male rats that cohabitate for five weeks with a stress-exposed female will exhibit a depression-like phenotype that is observable on behavioral and physiological measures. In addition, drawing from a comprehensive literature that describes the beneficial effects of prior exercise on stress-related behavior, we tested our second hypothesis that in males that were paired with a stressed female, prior voluntary exercise will diminish the impact of negative emotional contagion. We found that pair housing a healthy male with a stressed female led to emotional contagion; males gained less body weight, were anhedonic, demonstrated heightened anxiety-like behavior, had lower serum brain-derived neurotrophic factor (BDNF) levels, had decreased hippocampal BDNF-stimulated tyrosine receptor kinase B (TrkB) signaling and had increased pro-inflammatory cytokine expression in the hippocampus. For the most part, the five-week exercise window that occurred prior to pair housing had few effects in non-stress paired rats, but had partial, yet substantial protective effects in rats that were pair-housed with a stressed female. Specifically, stress-paired, exercised rats showed less depressive-like behavior, had partially preserved hippocampal BDNF-stimulated TrkB signaling, had normalized serum BDNF concentration, and had hippocampal cytokine and immediate early gene levels that were equivalent to controls. These preclinical findings introduce a new model of negative emotional contagion between dyads of male-female rats and support the view that inclusion of exercise programs would be beneficial for persons that may, in the future, be susceptible to negative emotional contagion.

Effects of voluntary exercise on plasma and urinary metabolites and gut microbiota in mice fed with high-fat-diet

Effects of voluntary exercise on plasma and urinary metabolites and gut microbiota in mice fed with high-fat-diet

The Effect of Voluntary Exercise and Prenatal Exposure to Sodium Valproate on Learning, Memory, and Anxiety of Rats' Offspring.

Background: Antiepileptic drugs, such as sodium valproate (SV), are teratogenic as their usage by the pregnant mother has been associated with an increased risk of major congenital abnormalities in the fetus. In this study, the effects of voluntary exercise and prenatal exposure to SV on learning, memory, and anxiety in rats’ offspring are investigatedMethods: In the present study, 70 female albino Wistar rats (200-240g) were used. The rats were categorized in seven groups: 1 and 2, pregnant rats with exposure to SV (10 mg/kg/day i.p) 3 and 4, pregnant rats with exposure to SV (20 mg/kg/day i.p) 5 and 6, pregnant rats with exposure to normal saline (0.4 ml/day i.p) and 7, pregnant rats with exposure to lamotrigine (20 mg/kg/day i.p). The even and odd groups were sedentary and voluntary exercise groups, respectively. Learning and memory were tested in male offspring using shuttle-box; anxiety was tested by elevated plus-maze (each group n=12). Statistical analyses were performed using the one-way ANOVA (the Tukey test) and/or two-way ANOVA on rankResults: The results showed that voluntary exercise in male rats caused improvement of latency and duration time in the dark box compared to sedentary groups (P=0.004). Moreover, the group administrated with 10 mg/kg SV showed better learning capability than the group administrated with 20 mg/kg SV. Voluntary exercise could also improve anxiety (P=0.001)Conclusion: This study indicated that exercise could increase learning capacity and improve memories in rats’ offspring whose mothers were exposed to SV. Voluntary exercise could improve anxiety too, and the effect was dose-dependent.

Sexual differences on effects of voluntary exercise on heart failure in DCM model mice.

Sexual differences on effects of voluntary exercise on heart failure in DCM model mice.

Effects of voluntary exercise and sex on multiply-triggered heroin reinstatement in male and female rats.

The rise in heroin addiction has heightened the need for novel and effective treatments. Physical exercise has been shown as an effective treatment for stimulant abuse in clinical and pre-clinical research. However, this treatment has not yet been tested on opioid addiction. This study examined the effects of physical activity (wheel running) on heroin-seeking in rats within a reinstatement paradigm (i.e., heroin relapse model). Female and male rats were trained to self-administer intravenous heroin (0.015 mg/kg). Once trained, rats were placed into extinction (i.e., heroin abstinence) for 21 days with continuous access to a locked or unlocked running wheel. After extinction, rats were tested for drug- (heroin, caffeine, and yohimbine) and cue-primed reinstatement of heroin-seeking. Females completed more wheel revolutions than males across all study phases. Access to an unlocked running wheel reduced extinction and reinstatement of heroin-seeking, with greater reductions in females than males across several reinstatement conditions. In the locked wheel group, female rats showed greater reinstatement of heroin-seeking than males across several priming conditions. Wheel running reduced heroin-seeking in male and female rats, with females showing a more robust effect during reinstatement. The locked wheel group allowed an examination of sex differences in heroin reinstatement, which revealed that females showed greater vulnerability to heroin reinstatement than males, but with no other sex differences observed in maintenance or extinction. Overall, the results indicate that voluntary physical exercise may be an effective treatment for heroin dependence in humans.

Opposite Effects of Voluntary Physical Exercise on β3-Adrenergic Receptors in the White and Brown Adipose Tissue.

Catecholamine effects via β3-adrenergic receptors are important for the metabolism of the adipose tissue. Physical exercise is a core component of antiobesity regimens. We have tested the hypothesis that voluntary wheel running results in enhancement of β3-adrenergic receptor gene expression in the white and brown adipose tissues. The secondary hypothesis is that dietary tryptophan depletion modifies metabolic effects of exercise. Male Sprague-Dawley rats were assigned for sedentary and exercise groups with free access to running wheels for 3 weeks. All animals received normal control diet for 7 days. Both groups were fed either by low tryptophan (0.04%) diet or by control diet (0.2%) for next 2 weeks. The β3-adrenergic receptor mRNA levels in response to running increased in the retroperitoneal and epididymal fat pads. The gene expression of uncoupling protein-1 (UCP-1) was increased in the brown, while unchanged in the white fat tissues. Unlike control animals, the rats fed by low tryptophan diet did not exhibit a reduction of the white adipose tissue mass. Tryptophan depletion resulted in enhanced concentrations of plasma aldosterone and corticosterone, but had no influence on exercise-induced adrenal hypertrophy. No changes in β3-adrenergic receptor and cell proliferation measured by 5-bromo-2'-deoxyuridine incorporation in left heart ventricle were observed. The reduced β3-adrenergic receptor but not enhanced uncoupling protein-1 gene expression supports the hypothesis on hypoactive brown adipose tissue during exercise. Reduction in dietary tryptophan had no major influence on the exercise-induced changes in the metabolic parameters measured.