Sionaldo Eduardo Ferreira

Does an Energy Drink Modify the Effects of Alcohol in a Maximal Effort Test

BACKGROUND There are popular reports on the combined use of alcohol and energy drinks (such as Red Bull and similar beverages, which contain caffeine, taurine, carbohydrates, etc.) to reduce the depressant effects of alcohol on central nervous system, but no controlled studies have been performed. The main purpose of this study was to verify the effects of alcohol, and alcohol combined with energy drink, on the performance of volunteers in a maximal effort test (cycle ergometer) and also on physiological indicators (oxygen uptake, ventilatory threshold, respiratory exchange rate, heart rate, and blood pressure), biochemical variables (glucose, lactate, insulin, cortisol, ACTH, dopamine, noradrenaline, and adrenaline), and blood alcohol levels. METHODS Fourteen healthy subjects completed a double-blind protocol made up of four sessions: control (water), alcohol (1.0 g/kg), energy drink (3.57 ml/kg Red Bull), and alcohol + energy drink, each 1 week apart. The effort test began 60 min after drug or control ingestion, and the dependent variables were measured until 60 min after the test. RESULTS Heart rate at the ventilatory threshold was higher in the alcohol and alcohol + energy drink sessions in comparison with control and energy drink sessions. Although in comparison to the control session, the peak oxygen uptake was 5.0% smaller after alcohol ingestion, 1.4% smaller after energy drink, and 2.7% smaller after the combined ingestion, no significant differences were detected. Lactate levels (30 min after drug ingestion, 30 and 60 min after the effort test) and noradrenaline levels (30 min after the effort test) were higher in the alcohol and alcohol + energy drink sessions compared with the control session. CONCLUSIONS The performance in the maximal effort test observed after alcohol + energy drink ingestion was similar to that observed after alcohol only. No significant differences between alcohol and alcohol + energy drink were detected in the physiological and biochemical parameters analyzed. Our findings suggest that energy drinks, at least in the tested doses, did not improve performance or reduce alterations induced by acute alcohol ingestion.

Can energy drinks reduce the depressor effect of ethanol? An experimental study in mice

Although the popularization of the combined use of alcoholic beverages and energy drinks (ED) containing caffeine, taurine and other substances has increased, there are no controlled experimental studies on the effects of ED alone or combined with ethanol. This work aimed at evaluating the effects of different doses of ED combined or not with ethanol, on the locomotor activity of Swiss mice. The administration of 3.57, 10.71 or 17.86 ml/kg of ED alone increased the locomotor activity of the animals in relation to a control group. Low doses of ethanol (0.5, 1.0 and 1.5 g/kg) alone or in combination with 10.71 ml/kg of ED did not affect their locomotor activity. However, the reduction of activity observed after 2.5 g/kg of ethanol was antagonized by 10.71 ml/kg of ED. Further studies on the mechanisms of this interaction are still needed.

O efeito das bebidas alcoólicas pode ser afetado pela combinação com bebidas energéticas? Um estudo com usuários

OBJETIVO: Avaliar em uma amostra de criterio, o padrao de uso de bebidas energeticas, isoladamente e em associacao com bebidas alcoolicas. METODOS: Cento e trinta e seis voluntarios (idade 24 ± 6 anos) que relataram ao menos um uso anterior de bebidas energeticas foram submetidos a uma entrevista padronizada sobre habitos de consumo de bebidas energeticas e alcoolicas. RESULTADOS: A maioria da amostra relatou usar bebidas energeticas tanto isoladamente (79%) como em combinacao com bebidas alcoolicas (76%), neste caso preferencialmente com uisque (90%), vodka (37%) ou cerveja (13%). Apos a ingestao isolada de bebidas energeticas, 61% relataram nao sentir nenhum efeito, 10% mencionaram aumento da alegria, 9% euforia, 9% insonia, 7% desinibicao e 24% aumento do vigor fisico. Dos que relataram uso combinado com alcool, 14% relataram nao sentir alteracao dos efeitos do alcool, mas 38% reportaram aumento de alegria, euforia (30%), insonia (11%), desinibicao (27%) e do vigor fisico (24%). Observou-se grande variabilidade no numero de usos de bebidas energeticas na vida (14 ± 16), mas certa regularidade na quantidade ingerida por ocasiao (1,5 ± 0,7 latas). CONCLUSOES: Os dados sugerem que os efeitos das bebidas energeticas sao bastante variaveis, dependendo provavelmente da dose ingerida e da sensibilidade individual. Alguns relatos sugerem que ha interacao com o alcool, expressa pelo aumento dos efeitos excitatorios ou reducao de seus efeitos depressores. Sao discutidos possiveis mecanismos farmacologicos subjacentes a esta combinacao.

Expression of behavioral sensitization to ethanol is increased by energy drink administration

Alcohol abuse and dependence are important medical, social and economical problems, affecting millions of people. A relatively recent habit among young people is mixing alcohol with energy drinks (ED), in spite of the risks involved may be higher than those associated with alcohol consumption alone. The mixture of alcohol and energy drinks, both with stimulant properties, may alter the perception of intoxication and could lead individuals to believe they are less drunk and can drink more or for longer periods of time. In animals, the repeated administration of ethanol can lead to a progressive increase of the locomotor stimulant effect, known as behavioral sensitization, a drug-dependent behavioral plasticity associated with vulnerability to addiction. As well as for addiction, there are clear individual differences in the level of sensitization to ethanol among species and even among individuals from the same strain. The present study assessed how ED affects the expression of ethanol sensitization. Female mice chronically treated with ethanol (2.4 g/kg) were classified as low-sensitized or high-sensitized. Two days later, different groups of mice were submitted to saline+water, ethanol+water or ethanol+ED systemic challenges. As expected, only the high-sensitized group expressed clear sensitization after ethanol administration. However, the administration of ethanol+ED triggered the sensitization expression in the low-sensitized group. These data indicate that the combined use of ED and ethanol can potentiate the stimulant and, consequently, the reward effects of ethanol in previously treated mice. If a similar process occurs in human beings, the use of ED can increase the risk of developing alcohol abuse or dependence.

The influence of subjective intensity control on perceived fatigue and capillary lactate in two types of resistance training

1 Abstract - Rating of perceived exertion (RPE) is a method used to control intensity in resistance training (RT). However, few studies have compared acute physiological and perceptual responses between different types of RT. The objective of this study was to compare the acute responses of lactate and perceived fatigue (PF) between manual resist- ance training (MRT) and free weight RT (FWRT) with intensity control by RPE, and to evaluate the correlation between lactate and PF in both interventions. Fourteen previously untrained men (40.29 ± 8.63 years, BMI = 26.53 ± 5.24 kg/m²) underwent single sessions of MRT and FWRT with intensity control by RPE (5-7 OMNI-RES). Lactate and PF were analyzed pre and post-test. Repeated measures ANOVA and the post hoc Bonferroni test were used for data analysis, adopting a significance level of 5% (P ≤ 0.05). The effect size was calculated to determine the magnitude of the response and Pearsons correlation coefficient was used to assess the association between lactate and PF. Both interventions increased post-test lactate compared to pre-test levels. However, the increase was greater for MRT. Post-test PF was increased when compared to pre-test levels in both protocols, with no difference between interventions. However, a greater effect size was observed for MRT. The correlation between PF and lactate was moderate in three of the four assess- ments. In conclusion, the same intensity zone in RPE may elicit different physiological responses in the two types of RT. Thus, the use of RPE for intensity control under these conditions should be viewed with caution.