Search

Competing Interests: Y. Le Bouc déclare des liens (interventions ponctuelles et prises en charge lors de congrès) avec Sandoz, Ipsen et Novo-Nordisk. X. Bigard déclare n’avoir aucun lien d’intérêts.

Recommending physical activity for primary prevention of chronic diseases. Low level of physical activity (i.e. inactivity) is recognized as the second preventable common risk factor of chronic diseases after the tobacco use. Nonlinear dose-effect relationships are found between the volume and intensity of physical activity, and the global mortality and incidence of chronic diseases. A sedentary behavior, characterized by prolonged periods of very low energy expenditure, is also related to the global mortality and the incidence of chronic diseases. The deleterious effects of sedentary behavior are especially marked beyond seven hours a day sitting, or three hours a day in watching the television. All the results of recent survey demonstrate that in order to reduce the incidence of chronic diseases, both physical activity recommendations and decrease in sedentary time are recommended, whatever the age of the population., Competing Interests: Les auteurs déclarent n’avoir aucun lien d’intérêts.

Aims: The aim of this study was to explore possible changes in body composition, blood glucose regulation, plasma growth hormone (GH), insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein-3 (IGFBP-3), and insulin concentrations of trained athletes in response to the intermittent fasting and dehydration of Ramadan observance., Methods: Nine trained male rugby players (age 19 +/- 2 years, height 1.78 +/- 0.74 m) were tested 3 times: before Ramadan (C), at the end of the first week (R1), and during the fourth week (R2). They performed a progressive cycle ergometer test at each visit. The work rate was increased in 6-min stages corresponding to 20, 30, 40, 50 and 60% of W max. Substrate oxidation was evaluated by indirect calorimetry. On each occasion, substrate and plasma hormone concentrations were measured at rest and at the end of the exercise., Results: Ramadan fasting induced a significant decrease in body mass and body fat (R2 vs. C, p < 0.001). Plasma concentrations of glucose, insulin, GH, IGF-1 and IGFBP-3 did not change significantly between C and R2, either at rest or following exercise., Conclusion: Ramadan fasting induces positive changes in body composition without disturbing glucose regulation or activity of the GH/IGF-1 system., (2008 S. Karger AG, Basel.)

Purpose: The aim of this study was to assess the effect of Ramadan fasting on substrate oxidation in trained athletes during moderate-intensity exercise., Methods: Nine trained men (age: 19+/-2 yr, Height: 1.78+/-0.74 m) were tested on three occasions: during a control period immediately before Ramadan (C), at the end of the first week (Beg-R), and during the fourth week of Ramadan (End-R). On each occasion, they performed submaximal cycle ergometer exercise, with work-rates that were increased progressively (loadings corresponding to 20, 30, 40, 50, 60% of Wmax). Steady-state substrate oxidation was evaluated by indirect calorimetry., Results: Participants showed significant decreases in body mass and body fat at the end of Ramadan, relative to initial control values (P<0.001). The daily food intake was also reduced during Ramadan (P<0.01). Haemoglobin concentrations and hematocrit were significantly higher at the end-Ramadan, both at rest (P<0.001 and P<0.0001 respectively) and after exercise, (P<0.05 and P<0.01 respectively) compared to control measurements made before Ramadan. At the end of Ramadan, our subjects had increased their fat utilization during exercise. The cross-over was observed at a higher intensity at the End-R (35% vs. 30% of Wmax, P<0.001). For the same power output, the Lipox max was also higher at the End-R, compared to control value (265+/-38 vs. 199.1+/-20 mg/min, P<0.001)., Conclusion: Ramadan fasting increases the lipid oxidation of trained athletes during submaximal exercise. The increased fat utilisation may be related to decreases in body mass and body fat content.

Objectives: We investigated the in situ properties of muscle mitochondria using the skinned fiber technique in patients with chronic heart failure (CHF) and sedentary (SED) and more active (ACT) controls to determine: 1) whether respiration of muscle tissue in the SED and ACT groups correlates with peak oxygen consumption (pVO(2)), 2) whether it is altered in CHF, and 3) whether this results from deconditioning or CHF-specific myopathy., Background: Skeletal muscle oxidative capacity is thought to partly determine the exercise capacity in humans and its decrease to participate in exercise limitation in CHF., Methods: M. Vastus lateralis biopsies were obtained from 11 SED group members, 10 ACT group members and 15 patients with CHF at the time of transplantation, saponine-skinned and placed in an oxygraphic chamber to measure basal and maximal adenosine diphosphate (ADP)-stimulated (V(max)) respiration rates and to assess mitochondrial regulation by ADP. All patients received angiotensin-converting enzyme (ACE) inhibitors., Results: The pVO(2) differed in the order CHF < SED < ACT. Compared with SED, muscle alterations in CHF appeared as decreased citrate synthase, creatine kinase and lactate dehydrogenase, whereas the myosin heavy chain profile remained unchanged. However, muscle oxidative capacity (V(max), CHF: 3.53 +/- 0.38; SED: 3.17 +/- 0.48; ACT: 7.47 +/- 0.73, micromol O(2).min(-1).g(-1)dw, p < 0.001 vs. CHF and SED) and regulation were identical in patients in the CHF and SED groups, differing in the ACT group only. In patients with CHF, the correlation between pVO(2) and muscle oxidative capacity observed in controls was displaced toward lower pVO(2) values., Conclusions: In these patients, the disease-specific muscle metabolic impairments derive mostly from extramitochondrial mechanisms that disrupt the normal symmorphosis relations. The possible roles of ACE inhibitors and level of activity are discussed.

Practical information is needed on the extent to which elite and competitive female athletes can continue to train and compete safely during pregnancy, without risk for themselves or their child, as well as advice for the postpartum period, including breast-feeding. Such information is also needed to recommend cycling for non-athlete women who wish to exercise. For this reason, the International Cycling Union (UCI) has produced this guide to provide information for all those who participate in recreational cycling activities and UCI sanctioned competitions during pregnancy. This policy has been developed utilising the AGREE II instrument and has had input from elite female cyclists, including those who have came back to compete following pregnancy. Supported by clinical evidence, the UCI encourages women to continue cycling throughout their pregnancy. Although cycling exercise is generally safe during pregnancy, some general principles are required for women, especially when cycling in the heat. No competitive cycling events included in the UCI calendar are possible beyond the 1st trimester of pregnancy, mainly to prevent the risk of trauma to the uterus and foetus in the event of an accident. However, the UCI encourages pregnant women to participate in recreational/leisure cycling as a form of physical activity throughout their pregnancy; but the ability to participate in organised recreational activities is only possible up to the end of the 1st trimester. Exercise, and especially cycling exercise, should be viewed as an important component to improve women's psychological health and common complaints during the postpartum period. Breast-feeding is highly recommended when women return to exercise and there is no impact of exercise on the quantity and quality of breast-milk. There are no significant disadvantages with regard to foetal and/or maternal conditions with high-intensity training programmes when they are subjectively tolerated and carefully monitored, at least during the first trimester of pregnancy. For the global population, exercises at moderate-intensity during pregnancy have many positive effects for both the mothers and their unborn children. That is why it is highly recommended that pregnant women begin or continue biking at moderate-intensity at least 150 minutes a week with at least 3 sessions of a duration longer than 30 minutes each. [ABSTRACT FROM AUTHOR]

An abstract of the study "Fiber-Type Specificity of VEGF Production in Single Muscle Fibers After a Single Bout of Exercise," by O. Birot and X. Bigard, is presented.