Nutrition
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High altitudes are a challenge for human physiology and for sports enthusiasts. Several reasons lead to deterioration in performance at high altitudes. Hypoxia owing to high altitude causes a breakdown of homeostasis with imbalance in several physiological systems, including the immune system. ⋯ Although the association between exercise and hypoxia has been shown to be more severe for the body owing to the sum of stressful agents, supplementation with carbohydrates and glutamine seems to play a relevant role in mitigating immunosuppressive effects. These findings, although limited by the fact that they are the result of very few studies, shed light on a relevant theme for sports physiology and nutrition and suggest that both supplements may be useful for athletes, visitors, and workers in high-altitude regions. The aim of this review was to discuss the effects of high-altitude hypoxia on the human body from the point of view of exercise immunology because it is known that transient immunosuppression after strenuous exercise and competition should be followed by reduction in training overload and worse performance.
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Comparative Study
Body composition measurement by air displacement plethysmography in pregnancy: Comparison of predicted versus measured thoracic gas volume.
Body composition measurements with air displacement plethysmography (ADP) define body volume, which must be corrected for thoracic gas volume (TGV). We hypothesized that physiologic changes owing to pregnancy could affect the accuracy of predicted TGV and introduce errors into body composition measurements. ⋯ Measuring TGV increases the accuracy of body composition measurement by ADP in overweight and obese women, particularly during the late stage of pregnancy.
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Randomized Controlled Trial
High doses of sodium bicarbonate increase lactate levels and delay exhaustion in a cycling performance test.
It is well established that ingestion of sodium bicarbonate (NaHCO3) causes metabolic alkalosis. However, there is no consensus in terms of optimal NaHCO3 doses leading to enhanced performance. This study aimed to determine the effects of different NaHCO3 doses on performance and lactate clearance in non-professional cyclists. ⋯ The present study found that 0.3 g · kg-1 BW NaHCO3 is effective in improving performance and improving blood lactate levels in cyclists compared with control and 0.1 g · kg-1 BW NaHCO3.
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Increased blood flow via vasodilation, metabolite production, and venous pooling contribute to the hyperemia and cellular swelling experienced during resistance training. It has been suggested that these effects play a role in hypertrophic adaptations. Over the past 2 decades, sport supplement products have been marketed to promote exercise hyperemia and intracellular fluid storage, thereby enhancing hypertrophy via acute swelling of myocytes. ⋯ Although we recognize that the literature is relatively scarce regarding these topics, a better comprehension and discussion of these determinants can lead to increased knowledge and might guide further research regarding the proposed mechanisms of action of the identified compounds. In this case, increased knowledge may contribute to the development of improved efficacy, new products, or direct new research to specifically investigate those secondary effects. The aim of this review was to bring into focus new perspectives associated with secondary physiological effects induced by supplementation and to determine their relevance.
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Although current guidelines for obesity treatment endorse lifestyle modifications to achieve weight loss, energy-restricted diets are still the most commonly used method for the management of overweight. Diet restriction, however, not only is ineffective in promoting long-term weight loss but also may have more costs than benefits, predisposing the individual to fat regain. Several physiological and psychological mechanisms protect the body against starvation and explain how food restriction can promote paradoxically the opposite of what it is planned to achieve, triggering changes in energy metabolism, endocrine function and, thus, body composition. New approaches that focus on behavioral treatment without diet restriction, such as nutritional coaching, are showing strong growth that arises as an innovative way to create sustainable and effective lifestyle changes.