Document Type : review article
Authors
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Department of Sports Biological Sciences, Faculty of Sports and Health Sciences, Shahid Beheshti University, Tehran, Iran
2
Department of Sports Biological Sciences. Faculty of Sports and Health Sciences. Shahid Beheshti University. Tehran. Iran
Abstract
abstract
Resistance exercise leads to the stimulation of muscle protein synthesis, known as exercise-induced muscle hypertrophy. Several hormonal and nutritional factors, directly or indirectly impacting cellular pathways activated by exercise, influence muscle protein synthesis. Among these factors, acute and chronic alcohol consumption disrupts the balance between anabolic and catabolic mechanisms And affects muscles and heart activity in a different process though debate remains regarding the precise mechanisms involved. This systematic review article discusses the effects of alcohol consumption on muscle protein synthesis and degradation, focusing on the hypertrophy pathway mTOR and hormones considered dominant in exercise-induced muscle protein synthesis. To conduct this study, Based on searches in Pub med, Google Scholar, and Web of Science regarding the impact of alcohol consumption on protein synthesis processes, with an emphasis on the mTOR pathway in skeletal muscle following resistance exercise, in the time frame of 2010 to 2024, the following keywords were used in the title and keywords: Protein synthesis, Alcohol, Ethanol, Skeletal muscle, mTOR signaling, Resistance exercise, and Hypertrophy. After reviewing the articles, a total of 68 articles were selected for the current research. The research results indicate a decrease in growth hormone, testosterone, and insulin-like growth factor along with a negative effect on mTOR due to acute alcohol consumption, ultimately leading to reduced hypertrophy. Twenty-four hours after alcohol consumption, a 15-20% decrease in basal protein synthesis in skeletal muscle is observed, mostly in Type II fibers, especially Type IIx fibers which provide the greatest response to muscular hypertrophy from exercise. Chronic alcohol consumption also increases cortisol levels and activates the ubiquitin-proteasome pathway, leading to the activation of atrophic pathways and subsequent muscle mass reduction. Alcohol abuse is associated with a 50% prevalence of alcoholic myopathy, which also causes abnormal hypertrophy and diastolic dysfunction in the left ventricle of the heart. Excessive or chronic alcohol consumption leads to cardiomyopathy or structural and functional abnormalities of the cardiac muscle.
Conclusion: Therefore, considering that alcohol consumption can have negative effects on muscle protein synthesis even up to one day after consumption and disrupt hypertrophic signaling pathways. In this regard, it also affects cardiovascular health, and athletes need to be aware of the detrimental effects and consequences that alcohol consumption may entail. Understanding the negative effects of alcohol on these physiological processes is crucial for promoting a healthy lifestyle and optimizing exercise outcomes.
Keywords: Ethanol, mTOR, Hypertrophy, Resistance Exercise
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