Effects of moderate alcohol consumption in response to a high-intensity interval training in healthy adults. The BEER-HIIT study

Abstract

Physical activity is an integral part of a healthy lifestyle and physical exercise is an excellent tool to preserve health, enhance well-being, and improve physical and mental performance. For that, the most effective physical exercises are those leading to improvements in physical fitness and, consequently, are part of a structured training program. High intensity interval training (HIIT) is a novel form of training particularly effective and efficient since it allows achieving results with less time investment. HIIT leads to improvements in body composition, reducing body fat levels, increasing fat free mass, and bone mineral content. HIIT also elicits improvements in aerobic capacity, resistance, and muscle strength. Indeed, physical activity enhances cognitive function including better processing speed, attention, and memory, also it shows positive associations with self-perceptions, self-esteem, and mental well-being in young adults. Recent studies have reported the positive effects of HIIT on cognitive function, however contradictory results have been found related to performance on the executive function tasks. Although gender differences are obvious in physical and metabolic mechanisms concerning exercise, this issue has not generally received much attention, and data derived from men should not be directly applicable to women. Although the multiple and negative effects of high intakes of alcohol have been widely studied and demonstrated, the effect of moderate alcohol doses after exercise is not clear and it is currently under debate. Some studies indicate that post-exercise alcohol intake may have detrimental effect on muscle recovery. Others investigations have suggested that beer consumption could be associated with increased waist circumference. Further, some research has showed that alcohol containing beverages may decrease performance, specifically affecting reaction time, fine motor control, levels of arousal, and judgement. However, we can find contradictory and inconclusive results. The main aims of this International Doctoral Thesis are to evaluate the combined effects of a highly demanding training program and moderate alcohol/beer consumption on physical performance (i.e. body composition and cardiorespiratory fitness and muscular strength (Section 1), on cognitive performance (Section 2), and on psychosocial parameters and mood state (Section 3). The present results show that 10 weeks of HIIT did not influence body weight, but significantly decreased fat mass and fat mass percentage while increasing lean mass. These positive effects were not affected by the concomitant regular intake of beer, or its alcohol equivalent, in moderate amounts (Study 1). Additionally, our 10-week HIIT program improved cardiorespiratory fitness and hand grip strength, while no influence determined by the concurrent daily intake of beer or ethanol in moderate amount was observed (Study 2). Although improvements were found in reaction time (Study 3) and cognitive function (Study 4) we cannot conclude that those benefits were elicited by our HIIT intervention. Interestingly, moderate alcohol consumption did not negatively influence those beneficial adaptations on cognition. Finally, a 10-week HIIT program improved overall psychosocial parameters and mood adaptations in healthy young adults (Study 5). Also, those benefits were not affected by moderate alcohol consumption. Collectively, the results from the present International doctoral Thesis enhance our understanding of the effects of a highly demanding training program on several physical variables, such as body composition and physical fitness, and psychosocial parameters. However, inconclusive results were found regarding to the effects of a high intensity training on cognitive performance in healthy young adults. Moreover, it provides novel information regarding to the role of moderate beer or ethanol consumption while training in healthy young adults.