Neurohumoral and Metabolic Response to Exercise in Water
ABSTRACT Atrial natriuretic peptide (ANP) stimulates lipid mobilization and lipid oxidation in humans. The mechanism appears to promote lipid mobilization during exercise. We tested the hypothesis that water immersion augments exercise-induced ANP release and that the change in ANP availability is associated with increased lipid mobilization and lipid oxidation. In an open randomized and cross-over fashion we studied 17 men (age 31+/-3.6 years; body mass index 24+/-1.7 kg/m(2); body fat 17+/-6.7%) on no medication. Subjects underwent two incremental exercise tests on a bicycle ergometer. One test was conducted on land and the other test during immersion in water up to the xiphoid process. In a subset (n=7), we obtained electromyography recordings in the left leg. We monitored gas exchange, blood pressure, and heart rate. In addition, we obtained blood samples towards the end of each exercise step to determine ANP, norepinephrine, epinephrine, lactate, free fatty acids, insulin, and glucose concentrations. Heart rate, systolic blood pressure, and oxygen consumption at the anaerobic threshold and during peak exercise were similar on land and with exercise in water. The respiratory quotient was mildly reduced when subjects exercised in water. Glucose and lactate measurements were decreased whereas free fatty acid concentrations were increased with exercise in water. Water immersion attenuated epinephrine and norepinephrine and augmented ANP release during exercise. Even though water immersion blunts exercise-induced sympathoadrenal activation, lipid mobilization and lipid oxidation rate are maintained or even improved. The response may be explained by augmented ANP release.
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ABSTRACT: Various nutritional supplements (herbs, vitamins, and micronutrients) improve responses and adaptations to resistance exercise. ANP is a heart hormone that contributes to fluid, electrolyte and blood pressure homeostasis through its natriuretic and vasodilative actions. In the present study, the adaptation of ANP in response to resistance exercise was investigated in rats supplemented with glutamine for five weeks. The results showed that supplementation with glutamine did not influence the number of ANP granules per atrial cardiocyte in sedentary animals. In exercised-trained rats, the number and diameter of the granules was significantly higher in comparison with the control group and in exercised animals supplemented with glutamine there was significant increase in the number and diameter of ANP granules compared with controls. Altogether, these data indicated that in resistance exercise rats, glutamine significantly enhances cardiac ANP thus implicating the beneficial effects of glutamine supplementation to the ANP system.03/2015; 5(1). DOI:10.1016/j.rbce.2013.03.001
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ABSTRACT: The present study investigated the difference in blood glucose concentration (Glu) response during an incremental swimming test before and after a ten-week training period and verified whether blood glucose threshold (GT) could be determined in competitive swimmers. 7 elite male university swimmers participated in this study. 2 incremental swimming tests were conducted in a swimming flume before and after a ten-week training period. Blood lactate concentration (Bla) and Glu were measured after each swimming step, and the velocities of the lactate threshold (VLT) and glucose threshold (VGT) were analyzed. VLT increased significantly after training (1.21±0.06 m x s(-1) pre-training, 1.31±0.10 m x s(-1) post-training, p<0.05), while Glu did not increase at the higher swimming intensity steps. GT was not determined at each trial. Our results show that lactate threshold (LT) improved significantly after the ten-week training period, while the Glu response during incremental swimming tests did not change. Therefore, GT could not be determined in elite competitive swimmers before and after training.International Journal of Sports Medicine 11/2011; 32(11):835-8. DOI:10.1055/s-0031-1279778 · 2.37 Impact Factor
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ABSTRACT: BACKGROUND: The influences of exercising on cytokine response, fatigue and cardiorespiratory values are important aspects of rehabilitation in persons with multiple sclerosis (PwMS). Exercise performed within these programs is often practised in water but the effects of immersion on PwMS have not been systematically investigated. OBJECTIVE: The objective of this study is to determine differences in cytokine and neurotrophin concentrations, fatigue and cardiorespiratory values in response to 3 week endurance training conducted on a cycle ergometer or an aquatic bike. METHODS: A randomized controlled clinical trial was conducted in 60 MS patients (Expanded Disability Status Scale range 1.0-6.5). Resting serum levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), Interleukin-6, soluble receptor of IL-6 and tumor necrosis factor alpha, and concentrations in response to cardiopulmonary exercise test (CPET), fatigue and cardiorespiratory values were determined at entry and discharge. Subjects performed daily 30 minute training at 60% of VO(2)max. RESULTS: Cytokines and neurotrophins showed no significant differences between groups over the training intervention. Within the water group BDNF resting and post-CPET concentrations (p<0.05) showed a significant increase and NGF tended to increase after the training intervention. Short-term effects on BDNF (CEPT) tended to increase at the start and significantly thereafter (p<0.05). No changes occurred in the land group. Other cytokines and fatigue scores remained unchanged over the training period. Cardiorespiratory values improved significantly over time within both groups. CONCLUSION: This study indicates that aquatic training activates BDNF regulation and can be an effective training method during rehabilitation in PwMS.Multiple Sclerosis 08/2012; 19(5). DOI:10.1177/1352458512458605 · 4.86 Impact Factor