Acute physical exercise under hypoxia improves sleep, mood and reaction time

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Daily intake of pasteurized orange juice decreases serum cholesterol, fasting glucose and diastolic blood pressure in adults

Previous studies have shown that fresh squeezed orange juice or juice from reconstituted concentrate can help prevent the development of atherosclerosis. Pasteurized orange juice presently represents the major orange juice available in the market, and because of this, it becomes necessary to determine the healthy benefits associated with this product. In this study we investigated the effect of regular consumption of pasteurized orange juice on the nutritional status, biochemical profile, and arterial blood pressure in healthy men and women. Men and women volunteered to consume pasteurized orange juice (500 mL·d–1 and 750 mL·d–1, respectively), for 8 weeks. Anthropometric, biochemical, hemodynamic, and dietary assessments were evaluated at baseline and at the end of the experimental period. Total cholesterol and LDL-C significantly decreased in both men and women after the consumption of orange juice, and an increase in HDL-C level was detected exclusively in women. Fasting glucose, diastolic blood pressure, and triglyceride levels dropped in men after the consumption of orange juice. Anthropometric variables did not change with orange juice consumption, only waist circumference decreased significantly in women. Consumption of orange juice increased the energy and carbohydrate intake for women; however, vitamin C and folate increased after the orange juice period for both men and women. Regular consumption of pasteurized orange juice by men (750 mL·d–1) and women (500 mL·d–1) reduced the risk of developing atherosclerosis, and increased the nutritional quality of their diets.

Efeitos do estímulo auditivo musical sobre a resposta autonômica cardíaca e parâmetros cardiorrespiratórios durante e após exercício submáximo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Exploratory study of electromyographic behavior of the vastus medialis and vastus lateralis at neuromuscular fatigue onset

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Manipulation effects of prior exercise intensity feedback by the Borg scale during open-loop cycling

Objective To verify the effects of exercise intensity deception by the Borg scale on the ratings of perceived exertion (RPE), heart rate (HR) and performance responses during a constant power output open-loop exercise. Methods Eight healthy men underwent a maximal incremental test on a cycle ergometer to identify the peak power output (PPO) and heart rate deflection point (HRDP). Subsequently, they performed a constant power output trial to exhaustion set at the HRDP intensity, in deception (DEC) and informed (INF) conditions: DEC-subjects were told that they would be cycling at an intensity corresponding to two categories below the RPE quantified at the HRDP; INF-subjects were told that they would cycle at the exact intensity corresponding to the RPE quantified at the HRDP. Results The PPO and power output at the HRDP obtained in maximal incremental tests were 247.5 +/- 32.1 W and 208.1 +/- 27.1 W, respectively. No significant difference in the time to exhaustion was found between DEC (525 +/- 244 s) or INF (499 +/- 224 s) trials. The slope and the first and second measurements of the RPE and HR parameters showed no significant difference between trials. Conclusions Psychophysiological variables such as RPE and HR as well as performance were not affected when exercise intensity was deceptively manipulated via RPE scores. This may suggest that unaltered RPE during exercise is a regulator of performance in this open-loop exercise.

Is there a relationship between the total volume of load lifted in bench press exercise and the rating of perceived exertion?

Aim. The purpose of the study was to investigate the relationship between the total volume of load lifted (TVLL) and the rating of perceived exertion (RPE) measures during different resistance training (RT) schemes using the bench press exercise. Methods. The present study was divided into two experiments. In the first experiment, 18 healthy men performed three different RT schemes: a strength oriented scheme (SS), a muscular endurance oriented scheme (ES) and a hypertrophy oriented scheme (HS). TVLL was calculated for each scheme. Mean-RPE and session-RPE were assessed. In the second experiment, 23 men performed two resistance exercise bouts at different intensities (50 %-1RM and 75%-1RM) with matched TVLL. Mean-RPE and session-RPE were also assessed. Results. SS and HS showed higher TVLL and greater RPE scores as compared to ES (P<0.05). No significant difference was observed between SS and HS. It was verified significant positive correlations between TVLL and session-RPE (SS r=0.63, HS r=0.64, ES r=0.56; P<0.05), and between mean-RPE and TVLL (SS r=0.55, HS r=0.52, ES r=0.47; P<0.05) for all schemes. No differences were observed for mean-RPE, session-RPE and TVLL between the 50%-1RM and 75%1RM. Significant positive relationships between TVLL and session-RPE (50 %-1RM r=0.61, 75 %-1RM r=0.66; p<0.05) and between TVLL and mean-RPE (50 %-1RM r=0.51, 75%1RM r=0.49; P<0.05) were observed. Conclusion. The results of this study have shown that the TVLL in RT influences RPE measures. These findings corroborates the existence of a relationship between total work performed (external training load) and perception of effort (internal training load).

Comparison between multiple sets and half-pyramid resistance exercise bouts for muscle damage profile

The present study compared the changes in markers of muscle damage after bouts of resistance exercise employing the Multiple-sets (MS) and Half-pyramid (HP) training systems. Ten healthy men (26.1 +/- 6.3 years), who had been involved in regular resistance training, performed MS and HP bouts, 14 days apart, in a randomised, counter-balanced manner. For the MS bout, participants performed three sets of maximum repetitions at 75%-1RM (i.e. 75% of a One Repetition Maximum) for the three exercises, starting with the bench press, followed by pec deck and decline bench press. For the HP bout, the participants performed three sets of maximum repetitions with 67%-1RM, 74%-1RM and 80%-1RM for the first, second and third sets, respectively, for the same three exercise sequences as the MS bout. The total volume of load lifted was equated between both bouts. Muscle soreness, plasma creatine kinase (CK) activity, myoglobin (Mb) and C-reactive protein (CRP) concentrations were assessed before and for three days after each exercise bout, and the changes over time were compared between MS and HP using two-way repeated measures ANOVA. Muscle soreness developed significantly (P<0.01) after both bouts, but no significant difference was observed between MS and HP. Plasma CK activity and Mb concentration increased significantly (P<0.01) without significant differences between bouts, and CRP concentration did not change significantly after either bout. These results suggest that the muscle damage profile is similar for MS and HP, probably due to the similar total volume of load lifted.

Induction of Psychosis by Delta 9-Tetrahydrocannabinol Reflects Modulation of Prefrontal and Striatal Function During Attentional Salience Processing

Context: The aberrant processing of salience is thought to be a fundamental factor underlying psychosis. Cannabis can induce acute psychotic symptoms, and its chronic use may increase the risk of schizophrenia. We investigated whether its psychotic effects are mediated through an influence on attentional salience processing. Objective: To examine the effects of Delta 9-tetrahydrocannabinol (Delta 9-THC) and cannabidiol (CBD) on regional brain function during salience processing. Design: Volunteers were studied using event-related functional magnetic resonance imaging on 3 occasions after administration of Delta 9-THC, CBD, or placebo while performing a visual oddball detection paradigm that involved allocation of attention to infrequent (oddball) stimuli within a string of frequent (standard) stimuli. Setting: University center. Participants: Fifteen healthy men with minimal previous cannabis use. Main Outcome Measures: Symptom ratings, task performance, and regional brain activation. Results: During the processing of oddball stimuli, relative to placebo, Delta 9-THC attenuated activation in the right caudate but augmented it in the right prefrontal cortex. Delta 9-Tetrahydrocannabinol also reduced the response latency to standard relative to oddball stimuli. The effect of Delta 9-THC in the right caudate was negatively correlated with the severity of the psychotic symptoms it induced and its effect on response latency. The effects of CBD on task-related activation were in the opposite direction of those of Delta 9-THC; relative to placebo, CBD augmented left caudate and hippocampal activation but attenuated right prefrontal activation. Conclusions: Delta 9-Tetrahydrocannabinol and CBD differentially modulate prefrontal, striatal, and hippocampal function during attentional salience processing. These effects may contribute to the effects of cannabis on psychotic symptoms and on the risk of psychotic disorders.

Acute Cardiorespiratory and Metabolic Responses During Resistance Exercise in the Lactate Threshold Intensity

The aims were both to determine lactate and ventilatory threshold during incremental resistance training and to analyze the acute cardiorespiratory and metabolic responses during constant-load resistance exercise at lactate threshold (LT) intensity. Ten healthy men performed 2 protocols on leg press machine. The incremental test was performed to determine the lactate and ventilatory thresholds through an algorithmic adjustment method. After 48 h, a constant-load exercise at LT intensity was executed. The intensity of LT and ventilatory threshold was 27.1 +/- 3.7 and 30.3 +/- 7.9% of 1RM, respectively (P=0.142). During the constant-load resistance exercise, no significant variation was observed between set 9 and set 15 for blood lactate concentration (3.3 +/- 0.9 and 4.1 +/- 1.4 mmol.L-1, respectively. P=0.166) and BORG scale (11.5 +/- 2.9 and 13.0 +/- 3.5, respectively. P=0.783). No significant variation was observed between set 6 and set 15 for minute ventilation (19.4 +/- 4.9 and 22.4 +/- 5.5L. min(-1), respectively. P=0.091) and between S3 and S15 for VO2 (0.77 +/- 0.18 and 0.83 +/- 0.16L. min(-1), respectively. P=1.0). Constant-load resistance exercise at LT intensity corresponds to a steady state of ventilatory, cardio-metabolic parameters and ratings of perceived exertion.

Expression of Clock Genes in Human Subcutaneous and Visceral Adipose Tissues

Disrupted circadian rhythms are associated with obesity and metabolic alterations, but little is known about the participation of peripheral circadian clock machinery in these processes. The aim of the present study was to analyze RNA expression of clock genes in subcutaneous (SAT) and visceral (VAT) adipose tissues of male and female subjects in AM (morning) and PM (afternoon) periods, and its interactions with body mass index (BMI). Ninety-one subjects (41 +/- 11 yrs of age) presenting a wide range of BMI (21.4 to 48.6 kg/m(2)) were included. SAT and VAT biopsies were obtained from patients undergoing abdominal surgeries. Clock genes expressions were evaluated by qRT-PCR. The only clock gene that showed higher expression (p < .0001) in SAT in comparison to VAT was PER1 of female (372%) and male (326%) subjects. Different patterns of expression between the AM and PM periods were observed, in particular REV-ERBa, which was reduced (p < .05) at the PM period in SAT and VAT of both women and men (women: similar to 53% lower; men: similar to 78% lower), whereas CLOCK expression was not altered. Relationships between clock genes were different in SAT vs. VAT. BMI was negatively correlated with SATPER1 (r = -.549; p = .001) and SATPER2 (r = -.613; p = .0001) and positively with VATCLOCK (r = .541; p = .001) and VATBMAL1 (r = .468; p = .007) only in women. These data suggest that the circadian clock machinery of adipose tissue depots differs between female and male subjects, with a sex-specific effect observed for some genes. BMI correlated with clock genes, but at this moment it is not possible to establish the cause-effect relationship. (Author correspondence: mzanquetta@gmail.com)

Strength training with and without a vibration platform is capable to modulate heart rate variability?

The current research compared resting heart rate variability (VFC) before and after 10 weeks of strength training in groups that used and did not use a vibration platform. Seventeen healthy men were divided into conventional strength training (TF) or strength training using a vibration platform with a frequency of 30 Hz (TF+V30) training groups. One repetition maximum load (1-RM) on half squat exercise and VFC measurements were determined pre- and post-training program. Both groups had improved 1-RM load after the program (15.1% in TF group and 16.4% in TF+V30 group), although this increase was changed in the same extent for the two groups and there was no difference in 1-RM load between groups pre- and post-training program. No significant difference was observed in resting VFC measurements between groups pre and post-training program, however the magnitude of the effect size was moderated (ES = 0.50-0.80) for some variables (R-R interval, standard deviation of all R-R interval - SDNN, RMSSD, log-transformed of low frequency - InLF, and log-transformed of high frequency - InHF) in TF+V30 group. It was concluded that 10 weeks of strength training program with or without the vibration platform provided similar increase in 1-RM load in both groups, and although some evidences in this study indicate that vibration can increase vagal activity analyzed by ES, in neither groups the strength training was able to change VFC significantly.

Circulating matrix metalloproteinases and their endogenous inhibitors in patients with erectile dysfunction

Erectile dysfunction (ED) may reflect vascular alterations associated with imbalanced matrix metalloproteinases (MMPs) activities. However, no previous study has compared MMPs levels in ED patients with those found in healthy subjects. We measured the circulating MMP-2, MMP-9, TIMP-1 and TIMP-2 levels in ED patients, with or without diabetes mellitus (DM), and in healthy controls. We studied 28 healthy men (control group), 35 men with ED (ED group), and 33 men with ED and DM (ED/DM group). MMP-2, MMP-9, TIMP-1 and TIMP-2 plasma levels were measured by enzyme-linked immunosorbent assay and zymography. We found no differences in MMP-9 levels (P>0.05) among groups. However, while patients in the ED group had similar TIMP-1 levels compared with those found in the control group, we found higher TIMP-1 levels and lower MMP-9/TIMP-1 ratios in the ED/DM group compared with controls (P<0.05). While both groups of patients (ED and ED/DM) had slightly lower MMP-2 levels compared with controls (P<0.05), we found no differences in TIMP-2 levels among the study groups (P>0.05), and no differences in MMP-2/TIMP-2 ratios (P>0.05). We found evidence indicating lack of significant alterations in circulating net MMP-9 and MMP-2 activities in patients with ED, and lower net MMP-9 activity in diabetic patients with ED. International Journal of Impotence Research (2012) 24, 38-43; doi:10.1038/ijir.2011.44; published online 15 September 2011

Leptin receptors in human skeletal muscle

[EN] Human skeletal muscle expresses leptin receptor mRNA; however, it remains unknown whether leptin receptors (OB-R) are also expressed at the protein level. Fourteen healthy men (age = 33.1 +/- 2.0 yr, height = 175.9 +/- 1.7 cm, body mass = 81.2 +/- 3.8 kg, body fat = 22.5 +/- 1.9%; means +/- SE) participated in this investigation. The expression of OB-R protein was determined in skeletal muscle, subcutaneous adipose tissue, and hypothalamus using a polyclonal rabbit anti-human leptin receptor. Three bands with a molecular mass close to 170, 128, and 98 kDa were identified by Western blot with the anti-OB-R antibody. All three bands were identified in skeletal muscle: the 98-kDa and 170-kDa bands were detected in hypothalamus, and the 98-kDa and 128-kDa bands were detected in thigh subcutaneous adipose tissue. The 128-kDa isoform was not detected in four subjects, whereas in the rest its occurrence was fully explained by the presence of intermuscular adipose tissue, as demonstrated using an anti-perilipin A antibody. No relationship was observed between the basal concentration of leptin in serum and the 170-kDa band density. In conclusion, a long isoform of the leptin receptor with a molecular mass close to 170 kDa is expressed at the protein level in human skeletal muscle. The amount of 170-kDa protein appears to be independent of the basal concentration of leptin in serum.

Cardiovascular responses to dynamic exercise with acute anemia in humans

[EN] We hypothesized that reducing arterial O2 content (CaO2) by lowering the hemoglobin concentration ([Hb]) would result in a higher blood flow, as observed with a low PO2, and maintenance of O2 delivery. Seven young healthy men were studied twice, at rest and during two-legged submaximal and peak dynamic knee extensor exercise in a control condition (mean control [Hb] 144 g/l) and after 1-1.5 liters of whole blood had been withdrawn and replaced with albumin [mean drop in [Hb] 29 g/l (range 19-38 g/l); low [Hb]]. Limb blood flow (LBF) was higher (P < 0.01) with low [Hb] during submaximal exercise (i.e., at 30 W, LBF was 2.5 +/- 0.1 and 3.0 +/- 0.1 l/min for control [Hb] and low [Hb], respectively; P < 0.01), resulting in a maintained O2 delivery and O2 uptake for a given workload. However, at peak exercise, LBF was unaltered (6.5 +/- 0.4 and 6.6 +/- 0.6 l/min for control [Hb] and low [Hb], respectively), which resulted in an 18% reduction in O2 delivery (P < 0.01). This occurred despite peak cardiac output in neither condition reaching >75% of maximal cardiac output (approximately 26 l/min). It is concluded that a low CaO2 induces an elevation in submaximal muscle blood flow and that O2 delivery to contracting muscles is tightly regulated.

Sperm analysis of patients after successful treatment of childhood acute lymphoblastic leukemia with chemotherapy

Survivors of childhood acute lymphoblastic leukemia (ALL) treated with radiotherapy are at risk for impaired fertility. Whether chemotherapy alone is also long-term gonadotoxic is unclear. We assessed gonadal function in 11 male ALL-survivors treated with the same chemotherapy regimen and compared sperm analysis to healthy men. While sex hormone levels were normal in all subjects, 5/11 survivors showed pathological sperm concentration and 4/11 a decreased total sperm count compared to WHO criteria. Compared to healthy controls, all quantitative parameters in semen analysis of survivors were decreased. This suggests that treatment with chemotherapeutic agents alone, even in moderate doses, might have a gonadotoxic effect.