Strenuous Exercise Session Research Articles

Exercise-induced ruptured renal tumour in a young patient with hereditary leiomyomata-associated renal cell carcinoma (HLRCC): a case report

BackgroundHereditary leiomyomatosis-associated renal cell carcinoma (HLRCC) is rare with only 300 families reported to date worldwide. Despite highlighting renal malignancy, it is infamous for its cutaneous and leiomyomatosis component as the more common cause of presentation. This report is to highlight the rare presentation of HLRCC which occurs in a teenager which is unfortunately complicated with exercise-induced renal tumour rupture.Case presentationA 22-year-old gentleman presented with severe right lower abdominal pain for 4 days, associated with fever and nausea following a session of strenuous exercise. He has first-degree relatives and second-degree relatives from his maternal side who were genetically tested positive for HLRCC. Clinical examination revealed a tender right lumbar and right iliac fossa region. A computed tomography of the kidneys demonstrated a ruptured right renal tumour with a large right renal subcapsular and contained right retroperitoneal hematoma. An emergency right radical nephrectomy was performed, and he recovered well. The histopathological examination was consistent with HLRCC associated ruptured right renal cell carcinoma.ConclusionIdentification of this underreported familial malignancy is paramount as the onset of neoplasia occurs much earlier in life. This necessitates screening of family members at a younger age, and the management is followed by life-long surveillance.

Mir186 and mir145 In vivo Evaluation and Enrichment in Rats Submitted to Treadmill Strenuous Exercise

Aims: The present study aimed to identify miRNAs differentially expressed in rats submitted to strenuous exercise and in silico investigation of the biological implication of the findings.
 Place and Duration of Study: The in vivo experiments and analyses were performed in the Laboratory of Biochemistry and Gene Expression – LABIEX of the Superior Institute of Biomedical Science – ISCB from the State University of Ceará. Between 2017-2020.
 Methodology: The study was performed using as subjects 2-month-old male wistar rats, which initially were submitted to 2-week adaptation training. Later the animals were separated in two distinct groups, control (C) and trained (T), where only T performed a single session of strenuous exercise, while C were not submitted to this treatment. The applied exercise protocol consisted in a running training in treadmill with speed constant increasing until the animal exhaustion which was measured by the animal refusal to keep running. After 24h, soleus muscle was desiccated and submitted to RNAseq sequencing protocols. Obtained data were statistically evaluated in R environment with EBSeq package, to characterize and predict the miRNAs and their targets were used bioinformatics tools Gene Cards, mi RBase enrichR and KEGG.
 Results: Two differentially expressed miRNAs were found, mir145 and mir 186, both with downregulated expression pattern in strenuous exercise. These miRNAs have a total of 1201 predicted target genes, 67 were repeated and mostly correlate to cardiovascular disease pathways, between those 5 were differentially expressed as down-regulated.
 Conclusion: In conclusion, the findings suggest that mir186 and mir145 down-regulation profile mediated by strenuous exercise implicates in the non-alteration of the target genes expression profile, and consequently did not mediate alterations in the pathways they are evolved, which are mainly related to signaling and disorders.

Forced running-induced rhabdomyolysis in the Sprague-Dawley rat: towards a rodent model of capture myopathy.

Capture myopathy (CM) is a metabolic disease associated with mortality in mass boma captured (MBC) wildlife. The condition is induced by theforced pursuit, capturing, and restraint of wild animals, although its causal biology remains to be confirmed. A core feature of MBC-CM is rhabdomyolysis, which is associated with myoglobinuria and hyperthermia. Towards developing a translational model of CM-associated rhabdomyolysis, we investigated forced treadmill running to induce physical exhaustion and trigger rhabdomyolysis in Sprague Dawley (SD) rats. Twenty-four (24) SD rats (12 per sex) were subjected to treadmill habituation in a speed-tiered approach. Forty-eight hours after the last habituation session, one strenuous exercise (SE) session was performed at 75% of the theoretical VO2MAX (30m/min) until animals reached physical exhaustion. Core and skin surface temperatures were measured before the SE session and after rats reached exhaustion, after which a 1-h-cumulative urine sample was collected, and the myoglobin content assayed. We show that most SE, but not control-exposed (non-exercise) rats presented with myoglobinuria, while core and surface body temperatures in both male and female rats were significantly higher post-exercise. This pre-clinical model framework shows potential for investigating the pathophysiology of MBC-CM.

Interleukin-6 ablation does not alter morphofunctional heart characteristics but modulates physiological and inflammatory markers after strenuous exercise

Interleukin-6 (IL-6) is associated with pathological cardiac hypertrophy and can be dramatically increased in serum after an acute strenuous exercise session. However, IL-6 is also associated with the increased production and release of anti-inflammatory cytokines and the inhibition of tumor necrosis factor-alpha (TNF-α) after chronic moderate exercise. To elucidate the relevance of IL-6 in inflammatory and hypertrophic signaling in the heart in response to an acute strenuous exercise session, we combined transcriptome analysis using the BXD mice database and exercised IL-6 knockout mice (IL-6KO). Bioinformatic analysis demonstrated that low or high-levels of Il6 mRNA in the heart did not change the inflammation- and hypertrophy-related genes in BXD mice strains. On the other hand, bioinformatic analysis revealed a strong positive correlation between Il6 gene expression in skeletal muscle with inflammation-related genes in cardiac tissue in several BXD mouse strains, suggesting that skeletal muscle-derived IL-6 could alter the heart's intracellular signals, particularly the inflammatory signaling. As expected, an acute strenuous exercise session increased IL-6 levels in wild-type, but not in IL-6KO mice. Despite not showing morphofunctional differences in the heart at rest, the IL-6KO group presented a reduction in physical performance and attenuated IL-6, TNF-α, and IL-1beta kinetics in serum, as well as lower p38MAPK phosphorylation, Ampkalpha expression, and higher Acta1 and Tnf gene expressions in the left ventricle in the basal condition. In response to strenuous exercise, IL-6 ablation was linked to a reduction in the pro-inflammatory response and higher activation of classical physiological cardiac hypertrophy proteins.

Transarterial Embolization of a Transverse Sinus Dural Arteriovenous Fistula: 2-Dimensional Operative Video.

A 40-yr-old male with no significant past medical history presented with sudden onset right-sided retro-orbital headache associated with vision loss after a session of strenuous exercise. Initial assessment with noncontrast head computed tomography at the local emergency department revealed a right sided occipital intracranial hemorrhage (ICH). On arrival the patient ad a left quadrantopsia with Glasgow Coma Scale of 15 and an ICH score of 0. A computed tomographic angiography showed a high density 6×9 mm vascular lesion associated with 2 tortuous vessels. Cerebral angiography revealed a right sided dural arteriovenous fistula, Cognard Type IV, with arterial feeders arising from dural branches of the right vertebral artery, the posterior division of the right middle meningeal artery and meningeal branches distal to the neuromeningeal trunk of the left ascending pharyngeal artery.1 Four days after the ICH event the patient was treated with endovascular Onyx embolization of the fistula, through a transradial approach. Immediate angiographic assessment showed complete obliteration of the dAVF. The patient was discharged home and recovered his visual field deficit over 3 mo. The following operative video includes a discussion of the endovascular technique and treatment nuances associated with the transarterial management of a dural arteriovenous fistula. Patient consent was given prior to the procedure and consent and approval for this operative video was waived due to the retrospective nature of this manuscript and the anonymized video material.

Profile of Biochemical and Oxidative Stress Markers in Male Athletes Following Strenuous Exercise Session

With the increasing number of people who participate in one form of exercise or the other, believing that it improves health and enhances professional sporting career, the question of its health benefit can only be answered with the knowledge of the metabolic changes that occur during exercise. This study therefore, was aimed at investigating the implications of physical exercise on some metabolic biomarkers, and to identify the changes that occur in subjects who undergo strenuous regular physical exercise in the tropics. Blood samples were collected from 86 male athletes and 100 male non-athletes aged between 22 and 30 years following established protocols. The athletes were at the peak of their training in preparation for a major sporting event and the blood samples were collected at rest and immediately after strenuous exercise sessions; while blood samples from the non-athletes were collected only at rest and served as control. The samples were prepared and used for the evaluation of some metabolic and oxidative stress markers. All experimental evaluations were done following well established methods. Result showed that serum concentrations of creatinine, urea, bilirubin, testosterone and cortisol all significantly increased in athletes after strenuous exercise. However, there was no statistical significant change in these biomarkers between athletes at rest and non-athletes. Also except glutathione reductase which significantly decreased in athletes after exercise, other oxidative stress markers assayed significantly increased in athletes after exercise; there was also no significant change between athletes at rest and non-athletes. From the result, this study concludes that strenuous exercise may increase oxidative stress in the cells, cause hemolysis or muscle damage and subsequent myoglobin degradation.

Strenuous Acute Exercise Induces Slow and Fast Twitch-Dependent NADPH Oxidase Expression in Rat Skeletal Muscle.

The enzymatic complex Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase (NOx) may be the principal source of reactive oxygen species (ROS). The NOX2 and NOX4 isoforms are tissue-dependent and are differentially expressed in slow-twitch fibers (type I fibers) and fast-twitch fibers (type II fibers) of skeletal muscle, making them different markers of ROS metabolism induced by physical exercise. The aim of this study was to investigate NOx signaling, as a non-adaptive and non-cumulative response, in the predominant fiber types of rat skeletal muscles 24 h after one strenuous treadmill exercise session. The levels of mRNA, reduced glycogen, thiol content, NOx, superoxide dismutase, catalase, glutathione peroxidase activity, and PPARGC1α and SLC2A4 gene expression were measured in the white gastrocnemius (WG) portion, the red gastrocnemius (RG) portion, and the soleus muscle (SOL). NOx activity showed higher values in the SOL muscle compared to the RG and WG portions. The same was true of the NOX2 and NOX4 mRNA levels, antioxidant enzymatic activities, glycogen content. Twenty-four hours after the strenuous exercise session, NOx expression increased in slow-twitch oxidative fibers. The acute strenuous exercise condition showed an attenuation of oxidative stress and an upregulation of antioxidant activity through PPARGC1α gene activity, antioxidant defense adaptations, and differential gene expression according to the predominant fiber type. The most prominent location of detoxification (indicated by NOX4 activation) in the slow-twitch oxidative SOL muscle was the mitochondria, while the fast-twitch oxidative RG portion showed a more cytosolic location. Glycolytic metabolism in the WG portion suggested possible NOX2/NOX4 non-regulation, indicating other possible ROS regulation pathways.

Yogurt Drink Effectively Rehydrates Athletes After a Strenuous Exercise Session

Abstract Dehydration and electrolyte imbalance as a result of prolonged strenuous exercise leads to poor thermoregulation and impaired muscle performance. Thus, appropriate rehydration during and after exercise with a solution that has a balanced combination of nutrients including electrolytes, carbohydrates and proteins is crucial in preventing the side effects of dehydration. Yogurt drink as a traditional drink with an appropriate nutritious content could be used as an alternative to expensive commercially available drinks for rehydrating athletes after long exercises in warm and humid environments and in developing countries. In this cross-over trial we examined the rehydration potential of yogurt drink in comparison to water and a commercial drink after a strenuous exercise (cycling) session in a hot and humid environment. Blood measurements included blood osmolality, serum glucose, hematocrit and serum electrolytes. Urine measurements included urine volume, osmolality and electrolyte concentrations. The results showed that early after rehydration Yogurt drink compared to water significantly increased urine sodium (mmol/L) (138.8 ± 93.4 vs. 90.0 ± 50.7, P < 0.01), urine potassium (mmol/L) (105.6 ± 55.1 vs. 35.8 ± 22.0, P < 0.05) and urine chloride (mmol/L) (113.2 ± 28.4 vs. 35.8 ± 25.1 P < 0.01). This degree of improvement was the same as with the commercial drink for urine sodium, potassium, and chloride. Yogurt drink prevented dehydration-induced changes in the blood as it stabilized the hematocrit and serum sodium, potassium and osmolality within the normal range after exercise. Finally, our results indicated that yogurt drink, as a natural and affordable rehydration option, can be considered to restore fluid and electrolyte losses after strenuous exercises in hot and humid environments.

The effect of acute intermittent exercise on pain threshold and tolerance in middle-aged tennis players

Aim: The purpose of this study is to examine the alterations in pain threshold and tolerance of middle-aged persons those who regularly play tennis at rest and following acute voluntary exercise. Methods: Fifty-nine recreationally-active persons aged 30-60 years participated in this study. Women and men separately were divided into 10-years groups, with 30-39, 40-49 and 50-59 years of age. Pressure pain threshold (PPT) and pain tolerance (PPT) measurements were recorded at rest and immediately following an acute exercise. PPT and PPTO values were measured from the biceps muscle of dominant arm by using a digital algometer. Singles tennis match was used as an acute voluntary exercise session, the duration of each tennis match (min) and rate of perceived exertion (RPE) were recorded. Results: No statistical differences were found in exercise duration or RPE scores among groups. RPE scores showed that tennis match played by participants was corresponded a strenuous exercise session. In all age groups, no statistical differences were found in baseline PPT or PPTO results in women or men. PPT and PPTO values were increased following exercise both in women and men. Although post-exercise PPT results were similar among age groups of women and men, PPTO values of men were found to be higher in all age groups of men in comparison with the same age groups of women. Conclusion: In conclusion, the present study revealed that one bout of voluntary exercise session resulted in gender-dependent differences in pain tolerance in middle-aged participants, and those middle-aged men were tolerated of pain at higher pressure levels following exercise in comparison with women at the same age.

Is The Exercise-Induced Increase in Central Arterial Stiffness a Risk Factor for Health?

: Central arterial stiffness (CAS) is an independent predictor of cardiovascular mortality. If in one side, exercise training can reduce CAS and protect health; on the other side, CAS might be increased in individuals with very strenuous training routines. This chronic increase in CAS is observed acutely, right after a strenuous exercise session. Both chronic and acute increases in CAS are associated with cardiovascular risk factors such as left ventricle hypertrophy, reduction in baroreceptor sensitivity, increased aneurism formation and stroke incidence; besides, they contribute to hypertension, myocardial infarction, congestive heart failure, dementia and atherosclerosis. However, there are many reasons to believe that trained individuals are protected by other training adaptations and that increased CAS would not be too dangerous in these cases. Nevertheless, even when CAS is increased through exercise training, other harmful adaptations (e g, left ventricle hypertrophy) are aroused together. After debating these questions along the text, it was concluded that individuals should make a complete clinical check-up when decided to face strenuous training routines. A new debate is suggested: personalized exercise programs might be prescribed according to individual cardiovascular risks including CAS and the guidelines for exercise prescriptions proposed by health organizations need to attend these special cases.

Melatonin decreases muscular oxidative stress and inflammation induced by strenuous exercise and stimulates growth factor synthesis.

Strenuous exercise is detrimental to athletes because of the overproduction of reactive oxygen species. Melatonin, a classic antioxidant, has been shown to exhibit beneficial effects regarding intense exercise and tissue repair. In this study, we evaluated the onset and resolution of inflammation in melatonin-treated and nontreated rats subjected to a strenuous exercise session. We also analyzed the formation of thiobarbituric acid reactive substances (TBARS) and the activities of catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). Control and treated rats were subjected to exhaustive exercise after a period of 10days of melatonin treatment (20mg/dL). Plasma and muscle levels of tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), cytokine-induced neutrophil chemoattractant-2-alpha/beta (CINC-2α/β), l-selectin, macrophage inflammatory protein-3-alpha (MIP-3α), and vascular endothelial growth factor (VEGF) were measured prior to, immediately after, and 2hr after exercise. Our data revealed decreases in the muscle concentrations of IL-1β (35%), TNF-α (13%), IL-6 (48%), and TBARS (40%) in the melatonin-treated group compared with the control group. We also observed decreases in the plasma concentrations of IL-1β (17%) in the melatonin-treated group. VEGF-α concentrations and SOD activity increased by 179% and 22%, respectively, in the melatonin-treated group compared with the control group. We concluded that muscle inflammation and oxidative stress resulting from exhaustive exercise were less severe in the muscles of melatonin-treated animals than in the muscles of control animals. Thus, melatonin treatment may reverse exercise-induced skeletal muscle inflammation and stimulate growth factor synthesis.

Baker's yeast β-glucan supplementation increases monocytes and cytokines post-exercise: implications for infection risk?

Strenuous aerobic exercise is known to weaken the immune system, and while many nutritional supplements have been proposed to boost post-exercise immunity, few are known to be effective. The purpose of the present study was to evaluate whether 10 d of supplementation with a defined source of baker's yeast β-glucan (BG, Wellmune WGP®) could minimise post-exercise immunosuppression. Recreationally active men and women (n 60) completed two 10 d trial conditions using a cross-over design with a 7 d washout period: placebo (rice flour) and baker's yeast BG (250 mg/d of β-1,3/1,6-glucans derived from Saccharomyces cerevisiae) before a bout of cycling (49 ± 6 min) in a hot (38 ± 2°C), humid (45 ± 2 % relative humidity) environment. Blood was collected at baseline (before supplement), pre- (PRE), post- (POST) and 2 h (2H) post-exercise. Total and subset monocyte concentration was measured by four-colour flow cytometry. Plasma cytokine levels and lipopolysaccharide (LPS)-stimulated cytokine production were measured using separate multiplex assays. Total (CD14⁺) and pro-inflammatory monocyte concentrations (CD14⁺/CD16⁺) were significantly greater at POST and 2H (P<0·05) with BG supplementation. BG supplementation boosted LPS-stimulated production of IL-2, IL-4, IL-5 and interferon-γ (IFN-γ) at PRE and POST (P<0·05). Plasma IL-4, IL-5 and IFN-γ concentrations were greater at 2H following BG supplementation. It appears that 10 d of supplementation with BG increased the potential of blood leucocytes for the production of IL-2, IL-4, IL-5 and IFN-γ. The key findings of the present study demonstrate that BG may have potential to alter immunity following a strenuous exercise session.

Effect of iTonic Whole-Body Vibration on Delayed-Onset Muscle Soreness Among Untrained Individuals

Attempts to reduce or eliminate delayed-onset of muscle soreness are important as this condition is painful and debilitating. The purpose of this study was to examine the effectiveness of whole-body vibration (WBV) massage and stretching exercises at reducing perceived pain among untrained men. Sixteen adult men (age, 36.6 +/- 2.1 yr) volunteered to perform a strenuous exercise session consisting of resistance training and repeated sprints. Subjects were randomly assigned to 1 of 2 recovery groups: a group performing WBV stretching sessions or a stretching group performing static stretching without vibration. Both groups performed similar stretches, twice per day for 3 days after the workout. The vibration group performed their stretches on the iTonic platform (frequency, 35 Hz; amplitude, 2 mm). Perceived pain was measured at 12, 24, 48, and 72 hours postworkout. Statistical analyses identified a significantly lower level of reported perceived pain at all postworkout measurement times among the WBV group (p < 0.05). No difference existed at the preworkout measurement time. The degree of attenuation of pain ranged from 22-61%. These data suggest that incorporating WBV as a recovery/regeneration tool may be effective for reducing the pain of muscle soreness and tightness after strenuous training.

Strenuous exercise increases late outgrowth endothelial cells in healthy subjects

Endothelial progenitor cells (EPCs) and late outgrowth endothelial cells (OECs) seem to play an important role in vessel formation. While EPCs seem to exert their function mainly through a paracrine effect, the OECs can develop into mature endothelial cells and form tubular structures. Exercise is known to increase angiogenic factors that can mobilize EPCs; however, the effect on OECs is not known. We investigated the response to a single session of strenuous exercise on OECs, vascular endothelial growth factor (VEGF) and inflammatory cell levels in the healthy. Eleven healthy subjects performed 1 h of spinning exercise. Blood samples were collected at 1, 6, 24 and 48 h post-exercise for cell culture and biochemical analysis. OEC colonies doubled one hour after the spinning session (baseline 4.5 +/- 4.3 vs. 9.0 +/- 3.7, P < 0.05). Serum VEGF increased from 194 +/- 107 pg/ml at baseline to 224 +/- 111 pg/ml after 1 h, p = ns and neutrophilic granulocytes increased from 3.73 +/- 1.38 at baseline to 9.08 +/- 10.5 at 1 h (P < 0.01). The increased levels of OECs, VEGF and neutrophilic granulocytes declined gradually at the following time points. VEGF levels and neutrophilic granulocytes were highly correlated to OEC levels, r = 0.903 (VEGF) and r = 0.85 (neutrophilic granulocytes), respectively. Strenuous physical activity increases OEC colonies and is correlated to serum VEGF and neutrophilic granulocytes levels. An acute exercise-induced inflammatory response might be responsible for the VEGF release and subsequent increase of OECs. The clinical importance of these findings remains to be elucidated.

Cytokine Responses To Strenuous Exercise In Elite Athletes And Sedentary Subjects

Several pro inflammatory cytokines induce fatigue and somnolence when administered exogenously. The involvement of TNFα and IL6 in modulation of fatigue has been indirectly suggested by several lines of clinical evidence. PURPOSE: Our main objective was to asses changes in plasma IL6 and TNFα as well as in TNFα release from Lipopolysaccharide (LPS) stimulated blood by peripheral blood mononuclear cells (PBMC's) in well-trained cyclists over a strenuous exercise session. Our second objective was to compare plasma IL6 and TNFα as well as the TNFα release from LPS stimulated blood by PBMC's in well-trained cyclists with sedentary subjects. METHODS: Eight well-trained cyclists performed a maximal incremental exercise test followed by a strenuous exercise protocol. Nine sedentary subjects performed a maximal incremental exercise test as well. Blood samples were obtained before, during and after the exercise session. Concentrations of plasma IL6 and TNFα as well as TNFα release from LPS stimulated blood by PBMC's were measured. RESULTS: Plasma IL6 was elevated after the strenuous exercise protocol in well trained cyclists (P = 0.02). The capacity of LPS stimulated PBMC's to release TNFα decreased over the maximal incremental exercise test (P = 0.05) and decreased even further over the strenuous exercise protocol (P = 0.001) in well trained cyclists whereas no changes were observed over the maximal incremental exercise test in sedentary subjects. Basal TNFα release capacity was lower in sedentary subjects compared to well-trained cyclists (P = 0.01). Basal concentrations of TNFα and IL6 were below the detection limit of 3 pg/ml. CONCLUSION: Plasma IL6 and the LPS induced capacity of PBMC's to release TNFα are affected by a strenuous cycling exercise (increased and decreased, respectively) in welltrained cyclists while these responses are absent in sedentary subjects.

Exercise and Calcium Supplementation

Exercise-induced sweat calcium losses have been reported as substantial in male athletes. The first aim of the study was to quantify the increase in 24-h total dermal calcium losses and the net changes in calcium retention in active sportswomen after a 1-h strenuous exercise session. A second aim was to determine the effectiveness of calcium supplementation to offset any calcium loss. Twenty-six premenopausal sportswomen completed three 8-d intervention phases in a randomized-order, crossover design. The three phases were placebo+no exercise (control), placebo+exercise, and 400 mg of calcium as calcium carbonate (TUMS Ultra) twice daily+exercise. The supervised exercise was 1 h.d(-1) cycling at 65-70% of heart rate reserve. A controlled diet of approximately 450 mg.d(-1) of calcium and 24-h pooled urine and fecal collections allowed determination of calcium balance on days 5-8 of each phase. Twenty-four-hour dermal collections were made at the end of each phase using a whole-body washdown procedure. Exercise increased (P<0.05) dermal calcium losses (means+/-SD, 92+/-49 vs 79+/-31 mg.d(-1) in the nonexercise intervention period), which was no longer significant (P=0.14) when calcium supplementation was provided (83+/-49 mg.d(-1)). Higher (P<0.01) urinary calcium excretion during calcium supplementation is suggestive of higher net calcium absorption. Exercise did not affect urinary calcium excretion indicating lack of compensation for dermal losses. Net calcium retention was positive only during the exercise+calcium supplementation intervention period. Calcium supplementation can correct for negative calcium balance attributable to low calcium dietary intake and additional dermal losses from exercise.

Physiological Strain and Perceptual Differences during Repeated-bout Exercise in the Heat

One of the biggest challenges facing numerous young athletes is attempting to train or perform safely and effectively in the heat. An even greater performance challenge and clinical risk for incurring heat injury is encountered when a young athlete has to train or compete again soon on the same day, following a prior heat exposure and strenuous exercise session or competition. PURPOSE: To test the hypothesis that young athletes will experience an increase in physiological strain and related ratings of perceptual discomfort during a second identical exercise bout (compared to the first) in the heat, with a one-hour recovery period (21°C) in between bouts, even when maintaining adequate hydration (6% carbohydrate-electrolyte drink; [Na+]: 21.1 mmoH-1). METHODS: 24 healthy, young soccer players (6 boys, 6 girls 12–13 y: 12.6 ± 0.5 y, 161.8 ± 7.5cm, 49.9 ± 7.9 kg, BMI: 18.6 ± 2.2; 6 boys, 6 girls 16–17 y: 16.5 ± 0.5y, 166.0 ± 8.0 cm, 61.0 ± 8.6 kg, BMI: 21.8 ± 2.0) each completed two 80-min intermittent exercise (treadmill: 60% VO2max; cycle ergometer: 40% VO2max) sessions in the heat (33°C; relative humidity: 48.9 ± 6.0%) on the same day. RESULTS: Sweat loss incurred during each bout (B) of exercise was similar within each age group (12–13 yB1: 943.6 ± 237.1 ml, B2: 955.5 ± 250.3 ml; 16–17yB1: 1382.2 ± 480.7 ml, B2: 1373.1 ± 472.2 ml). Area under the curve (AUC) was not statistically different (p>0.05) between exercise bouts for core body temperature (12–13 y B1 peak: 38.6 ± 0.4°C, B2: 38.4 ± 0.2°C; 16–17y B1 peak: 38.8 ± 0.7°C, B2: 38.7 ± 0.6°C), physiological strain index (PSI) (12–13 yB1 peak: 7.9 ± 0.9, B2: 7.5 ± 0.7; 16–17 yB1 peak: 8.1 ± 1.5,B2: 7.9 ± 1.4), or thermal sensation for any age/gender sub-group or for all subjects combined. However, rating of perceived exertion AUC for all subjects combined was higher (p=0.0002) during B2 (B1 peak: 15.3 ± 2.0; B2: 16.2 ± 2.2), with the biggest difference shown in the older boys. Notably, 4 subjects experienced a consistently higher core temperature and PSI throughout exercise B2 compared to B1. CONCLUSION: With fit, young athletes, one hour of cool-down and rehydration, following 80 min of exercise in the heat, is insufficient time to avert greater perception of effort, and for some, greater physiological strain, during a subsequent identical exercise bout. Supported by Gatorade Sports Science Institute

Response of bone metabolism related hormones to a single session of strenuous exercise in active elderly subjects

Objective: To evaluate the effect of strenuous exercise on bone metabolism and related hormones in elderly subjects. Methods: Twenty one active elderly subjects (11 men and 10 women; mean age...

Conseqüências do exercício para o metabolismo da glutamina e função imune

Para o atleta, o objetivo do treinamento é aperfeiçoar sua capacidade física para obtenção do melhor desempenho em competições. Isso o leva a procurar os mais novos e eficientes métodos de treinamento. Um aspecto importante do programa de treinamento é o período de recuperação entre as sessões de exercícios, imprescindível para que ocorram as adaptações fisiológicas, como as alterações morfológicas e a supercompensação das reservas energéticas. A liberação de glutamina pelos músculos esqueléticos é aumentada durante o exercício. Como conseqüência, o conteúdo muscular de glutamina diminui após um exercício extenuante. Este aminoácido, entretanto, é muito importante para a funcionalidade dos leucócitos (linfócitos, macrófagos e neutrófilos). Portanto, após um exercício intenso, a concentração plasmática de glutamina diminui, suprimindo a função imune e tornando o indivíduo mais suscetível a infecções respiratórias. Nesta revisão são discutidas as implicações do exercício sobre o metabolismo dos músculos esqueléticos e leucócitos.