Serodiagnosis of Babesia equi in horses submitted to exercise stress

A complement fixation test (CFT), performed in microtitre plates, based upon the use of crude antigenic preparation of Babesia equi was adapted for the detection of antibodies in serum of infected horses. The indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) were also used for the immunodiagnosis of B. equi. Serum samples from 15 apparently healthy horses, previously conditioned to a high-speed equine treadmill, were taken before and after exercise. All the samples analyzed were positive for B. equi infection. There were no significant differences (P<0.01) between these 3 tests, or the condition of rest or stress. The combined use of CFT and IFAT or ELISA should be recommended in order to enable veterinary services to more efficiently prevent introduction of infected horses into disease-free areas.

Effects of caffeine on time to exhaustion in exercise performed below and above the anaerobic threshold

Controversy still exists concerning the potential ergogenic benefit of caffeine (CAF) for exercise performance. The purpose of this study was to compare the effects of CAF ingestion on endurance performance during exercise on a bicycle ergometer at two different intensities, i.e., approximately 10% below and 10% above the anaerobic threshold (AT). Eight untrained males, non-regular consumers of CAF, participated in this study. AT, defined as the intensity (watts) corresponding to a lactate concentration of 4 mM, was determined during an incremental exercise test from rest to exhaustion on an electrically braked cycle ergometer. On the basis of these measurements, the subjects were asked to cycle until exhaustion at two different intensities, i.e., approximately 10% below and 10% above AT. Each intensity was performed twice in a double-blind randomized order by ingesting either CAF (5 mg/kg) or a placebo (PLA) 60 min prior to the test. Venous blood was analyzed for free fatty acid, glucose, and lactate, before, during, and immediately after exercise. Rating of perceived exertion and time to exhaustion were also measured during each trial. There were no differences in free fatty acids or lactate levels between CAF and PLA during and immediately after exercise for either intensity. Immediately after exercise glucose increased in the CAF trial at both intensities. Rating of perceived exertion was significantly lower (CAF = 14.1 ± 2.5 vs PLA = 16.6 ± 2.4) and time to exhaustion was significantly higher (CAF = 46.54 ± 8.05 min vs PLA = 32.42 ± 14.81 min) during exercise below AT with CAF. However, there was no effect of CAF treatment on rating of perceived exertion (CAF = 18.0 ± 2.7 vs PLA = 17.6 ± 2.3) and time to exhaustion (CAF = 18.45 ± 7.28 min vs PLA = 19.17 ± 4.37 min) during exercise above AT. We conclude that in untrained subjects caffeine can improve endurance performance during prolonged exercise performed below AT and that the decrease of perceived exertion can be involved in this process

Post-exercise changes in blood pressure, heart rate and rate pressure product at different exercise intensities in normotensive humans

To evaluate the effect of exercise intensity on post-exercise cardiovascular responses, 12 young normotensive subjects performed in a randomized order three cycle ergometer exercise bouts of 45 min at 30, 50 and 80% of VO2peak, and 12 subjects rested for 45 min in a non-exercise control trial. Blood pressure (BP) and heart rate (HR) were measured for 20 min prior to exercise (baseline) and at intervals of 5 to 30 (R5-30), 35 to 60 (R35-60) and 65 to 90 (R65-90) min after exercise. Systolic, mean, and diastolic BP after exercise were significantly lower than baseline, and there was no difference between the three exercise intensities. After exercise at 30% of VO2peak, HR was significantly decreased at R35-60 and R65-90. In contrast, after exercise at 50 and 80% of VO2peak, HR was significantly increased at R5-30 and R35-60, respectively. Exercise at 30% of VO2peak significantly decreased rate pressure (RP) product (RP = HR x systolic BP) during the entire recovery period (baseline = 7930 ± 314 vs R5-30 = 7150 ± 326, R35-60 = 6794 ± 349, and R65-90 = 6628 ± 311, P<0.05), while exercise at 50% of VO2peak caused no change, and exercise at 80% of VO2peak produced a significant increase at R5-30 (7468 ± 267 vs 9818 ± 366, P<0.05) and no change at R35-60 or R65-90. Cardiovascular responses were not altered during the control trial. In conclusion, varying exercise intensity from 30 to 80% of VO2peak in young normotensive humans did not influence the magnitude of post-exercise hypotension. However, in contrast to exercise at 50 and 80% of VO2peak, exercise at 30% of VO2peak decreased post-exercise HR and RP.

Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats

Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white) and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg) was administered orally for three months to male Wistar rats weighing 200 ± 50 g before exercise and to non-exercised rats (N = 8/group). The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05) after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05) by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type.

Subacute effects of a maximal exercise bout on endothelium-mediated vasodilation in healthy subjects

We evaluated vascular reactivity after a maximal exercise test in order to determine whether the effect of exercise on the circulation persists even after interruption of the exercise. Eleven healthy sedentary volunteers (six women, age 28 ± 5 years) were evaluated before and after (10, 60, and 120 min) a maximal exercise test on a treadmill. Forearm blood flow (FBF) was measured by venous occlusion plethysmography before and during reactive hyperemia (RH). Baseline FBF, analyzed by the area under the curve, increased only at 10 min after exercise (P = 0.01). FBF in response to RH increased both at 10 and 60 min vs baseline (P = 0.004). Total excess flow for RH above baseline showed that vascular reactivity was increased up to 60 min after exercise (mean ± SEM, before: 526.4 ± 48.8; 10 min: 1053.0 ± 168.2; 60 min: 659.4 ± 44.1 ml 100 ml-1 min-1 . s; P = 0.01 and 0.02, respectively, vs before exercise). The changes in FBF were due to increased vascular conductance since mean arterial blood pressure did not change. In a time control group (N = 5, 34 ± 3 years, three women) that did not exercise, FBF and RH did not change significantly (P = 0.07 and 0.7, respectively). These results suggest that the increased vascular reactivity caused by chronic exercise may result, at least in part, from a summation of the subacute effects of successive exercise bouts.

Effects of type of physical exercise and leisure activities on the depression scores of obese Brazilian adolescent girls

Several studies have indicated that depressive states may lead to hypokinesia with diminished metabolic rate and energy use. Hypokinesia associated with certain eating behaviors may lead to an unfavorable energy balance that can contribute to the emergence and prevalence of obesity among children and adults. The purpose of the present study was to examine the possibility of reducing depression inventory scores in female adolescents with third-degree obesity while testing the effectiveness of different exercise programs in reducing anxiety and depression scores. The sample consisted of 40 female subjects (mean age 16 ± 1.56 years) divided into 4 groups (aerobic training, anaerobic training, leisure activities, and control). Subjects had a body mass index of 95% or more in relation to the 50th percentile. The aerobic program consisted of three ergometric bicycle sessions per week over a 3-month period (12 weeks) and the activities were prescribed after determining the anaerobic ventilatory threshold (VO2 threshold). Anaerobic training was based on the Wingate anaerobic power test. The leisure program consisted of a varied range of activities (games, exercises, etc.). A nutritionist interviewed the members of these two groups and the control group every week in order to adapt them to the nutritional guidelines proposed for the study. The study showed that all three programs (aerobic exercise, anaerobic exercise and leisure activities) were effective in reducing body mass. However, we found a significant reduction when analyzing the depression scores only for aerobic exercise (18.9 ± 9.33 to 10.6 ± 9.56 or 43.9%) but no significant alterations for anaerobic exercise (11.36 ± 5.23 to 9.63 ± 4.78 or 15.22%) and leisure (17.28 ± 7.55 to 15.07 ± 7.54 or 12.78%), thus indicating that in principle this type of activity could be included to improve emotional well-being of obese adolescent girls.

Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities

This study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50% of the difference between the first (LT1) and second (LT2) lactate breakpoint for moderate exercise (below LT2) and at 25% of the difference between the maximal load and LT2 for heavy exercise (above LT2) until exhaustion. Forty-eight hours before each experimental session, subjects performed a 90-min cycling exercise followed by 5-min rest periods and a subsequent 1-min cycling bout at 125% VO2max/1-min rest periods until exhaustion to deplete muscle glycogen. A diet providing 10% (CHOlow) or 65% (CHOmod) energy as carbohydrates was consumed for 2 days until the day of the experimental test. In the exercise below LT2, time to exhaustion did not differ between the CHOmod and the CHOlow diets (57.22 ± 24.24 vs 57.16 ± 25.24 min). In the exercise above LT2, time to exhaustion decreased significantly from 23.16 ± 8.76 min on the CHOmod diet to 18.30 ± 5.86 min on the CHOlow diet (P < 0.05). The rate of carbohydrate oxidation, respiratory exchange ratio and blood lactate concentration were reduced for CHOlow only during exercise above LT2. These results suggest that muscle glycogen depletion followed by a period of a low carbohydrate diet impairs high-intensity exercise performance.

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V CW) = rib cage (V RC) + abdomen (V AB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) V CW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of V CW regulation as EEV CW increased non-linearly in 17/30 "hyperinflators" and decreased in 13/30 "non-hyperinflators" (P < 0.05). EEV AB decreased slightly in 8 of the "hyperinflators", thereby reducing and slowing the rate of increase in end-inspiratory (EI) V CW (P < 0.05). In contrast, decreases in EEV CW in the "non-hyperinflators" were due to the combination of stable EEV RC with marked reductions in EEV AB. These patients showed lower EIV CW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIV CW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment.

Environmental issues and international relations, a new global (dis)order - the role of International Relations in promoting a concerted international system

Is it possible to talk about the rise of a new global (dis)order founded on the challenges posed by environmental issues? Through the review of the state of the art on the subject, this article analyzes the growing importance of the environment, and natural resources in particular, in international relations; and aims to raise awareness among International Relations scholars to the potential positive impact of the development of the discipline in integration with global environmental change studies.

Reshaping European Union development policy: collective choices and the new global order

Abstract The European Union (EU) is one of the world´s leading donors in official development assistance (ODA) to give a strong weight in the relationship with recipient partner countries, in particular with those that are more dependent on it. Besides the material weight of its funding, the EU has retained historical ties and influence in diplomatic, political and economic terms in many of its ODA recipient partner countries (particular in Sub-Saharan Africa). Since the 2000s, the EU development policy has not only undergone major structural changes in its institutional framework but also has started to face a new international aid scenario. This paper explores why a normative-based EU development policy is being challenged by reformed EU institutions and a new global order, and how the EU is attempting to respond to this context in face of the deepest recession since the end of the Second World War.

Validation of psychosocial scales for physical activity in university students

OBJECTIVE Translate the Patient-centered Assessment and Counseling for Exercise questionnaire, adapt it cross-culturally and identify the psychometric properties of the psychosocial scales for physical activity in young university students.METHODS The Patient-centered Assessment and Counseling for Exercise questionnaire is made up of 39 items divided into constructs based on the social cognitive theory and the transtheoretical model. The analyzed constructs were, as follows: behavior change strategy (15 items), decision-making process (10), self-efficacy (6), support from family (4), and support from friends (4). The validation procedures were conceptual, semantic, operational, and functional equivalences, in addition to the equivalence of the items and of measurements. The conceptual, of items and semantic equivalences were performed by a specialized committee. During measurement equivalence, the instrument was applied to 717 university students. Exploratory factor analysis was used to verify the loading of each item, explained variance and internal consistency of the constructs. Reproducibility was measured by means of intraclass correlation coefficient.RESULTS The two translations were equivalent and back-translation was similar to the original version, with few adaptations. The layout, presentation order of the constructs and items from the original version were kept in the same form as the original instrument. The sample size was adequate and was evaluated by the Kaiser-Meyer-Olkin test, with values between 0.72 and 0.91. The correlation matrix of the items presented r < 0.8 (p < 0.05). The factor loadings of the items from all the constructs were satisfactory (> 0.40), varying between 0.43 and 0.80, which explained between 45.4% and 59.0% of the variance. Internal consistency was satisfactory (α ≥ 0.70), with support from friends being 0.70 and 0.92 for self-efficacy. Most items (74.3%) presented values above 0.70 for the reproducibility test.CONCLUSIONS The validation process steps were considered satisfactory and adequate for applying to the population.

Factors associated with dietary supplement use by people who exercise at gyms

OBJECTIVE To assess the factors associated with the use of dietary supplements by people who exercise at gyms.METHODS A cross-sectional study with a sample defined by convenience, considering the number of gyms registered in the Conselho Regional de Educação Física (Regional Council of Physical Education) of Sao Luis, MA, Northeastern Brazil, from July 2011 to July 2012. The final sample comprised 723 individuals who exercise at gyms. The dependent variable was supplement use, and the explanatory variables were length of time and motivation of the physical exercises, duration, goal and self-perception of training, weekly frequency of gym attendance, sex, age, educational attainment, self-perception of body weight, smoking and self-perception of diet. The association between variables was analysed by hierarchical Poisson regression based on a theoretical model.RESULTS Supplement use was reported by 64.7% of the participants. Most of the sample was male (52.6%). The most frequent age group was 20 to 39 years (74.4%). Most participants (46.1%) had been exercising for over a year. The following variables were associated with supplement use: self-perceiving body weight as below ideal (p < 0.001), smoking (p < 0.001), exercising for 7 to 12 months (p = 0.028) or more than one year (p < 0.001), spending more than two hours at the gym (p = 0.051), and perceiving training as moderate (p = 0.024) or intense (p = 0.001).CONCLUSIONS The use of supplements lacks proper professional guidance, being motivated by individuals unsatisfied with their low body weight and who perceive their workout as intense, which raises the need for monitoring this population.

Muscarinic antibodies and heart rate responses to dynamic exercise and to the Valsalva maneuver in chronic chagasic patients

We have studied the cardiac chronotropic responses to the Valsalva maneuver and to dynamic exercise of twenty chronic chagasic patients with normal left ventricular function and no segmental wall abnormalities by two-dimensional echocardiogram. The absolute increase in heart rate of the patients (Δ = 21.5 ± 10 bpm, M±SD) during the maneuver was significantly diminished when compared to controls (Δ = 31.30 ± 70, M±SD, p = 0.03). The minimum heart rate (58.24 ± 8.90 vs. 62.80 ± 10, p = 0.68) and the absolute decrease in heart rate at the end of the maneuver (Δ = 38.30 ± 13 vs. Δ = 31.47 ± 17, p = 0.10) were not different from controls. The initial heart rate acceleration during dynamic exercise (Δ = 12 ± 7.55 vs. Δ = 19 ± 7.27, M±SD, p = 0.01) was also diminished, but the heart rate recovery during the first ten seconds was more prominent in the sero-positive patients (Median: 14, Interquartile range: (9.75-17.50 vs. 5(0-8.75, p = 0.001). The serum levels of muscarinic cardiac auto-antibodies were significantly higher in the chagasic patients (Median: 34.58, Interquartile Range: 17-46.5, Optical Density) than in controls (Median: 0, Interquartile Range: 0-22.25, p = 0.001) and correlated significantly and directly (r = 0.68, p = 0.002) with early heart rate recovery during dynamic exercise. The results of this investigation indirectly suggest that, the cardiac muscarinic auto-antibodies may have positive agonist effects on parasympathetic heart rate control of chagasic patients.