Subjective State, Blood Pressure, and Behavioral Control Changes Produced by an “Energy Shot”

Abstract

Background: Energy drinks and energy shots are popular consumer beverages that are advertised to increase feelings of alertness. Typically, these products include high levels of caffeine, a mild psychostimulant drug. The scientific evidence demonstrating the specific benefits of energy products to users in terms of subjective state and objective performance is surprisingly lacking. Moreover, there are rising health concerns associated with the use of these products. Therefore, the purpose of this study was to investigate the acute effects of a popular energy shot (5-Hour Energy Ò ) on subjective and objective measures that were assessed hourly for 6 hours following consumption. Methods: Participants (n = 14) completed a three-session study where they received the energy shot, a placebo control, and no drink. Following dose administration, participants completed subjective Profile of Mood States ratings hourly for 6 hours. Participants also repeatedly completed a behavioral control task (the cued go/no-go task) and provided blood pressure and pulse rate readings at each hour. Results: Consumption of the energy shot did improve subjective state, as measured by increased ratings of vigor and decreased ratings of fatigue. However, the energy shot did not alter objective performance, which worsened over time. Importantly, the energy shot elevated both systolic and diastolic blood pressure. Conclusions: Consumption of one energy shot may only result in modest benefits to subjective state. Individuals with preexisting hypertension or other medical conditions should be cautious about using these new consumer products.

Acute effects of energy drinks in medical students

“…Several studies have shown that energy drinks exerted different effects on BP, but the use of different volumes and the concentration of components [16,21] or the fact that the beverages tested were prepared using only some of the components of the commercial brands [22] may be the reasons for this disagreement. However, some studies demonstrated an increase in SBP and DBP after energy drink intake [20,21], and one case of reversible hypertension induced by energy drinks was reported [47]. Caffeine promotes endothelial dysfunction and activates the sympathetic nervous system [48], which may generate the increase in BP values.…”

“…It is important to inquire more profoundly about the multiple effects of energy drinks to determine more precisely the potential harmful actions and the real effects on mental and physical performance [20,22] to compare the results with the proclaimed effects [84], according with the existing evidence. This further research is fundamental to providing correct information to consumers, especially adolescents and their parents [6], including health science students, who should paradoxically become more aware of such information.…”

“…Consumers 1 3 [19]. However, few studies investigated the acute cardiovascular and neurological effects [20][21][22] of energy drinks, and most of these studies evaluated only a single drink or beverages with a similar composition of commercial energy drinks. Parameters such as stress, anxiety and cortisol were not assessed in these studies.…”

Energy Drinks and Their Impact on the Cardiovascular System: Potential Mechanisms

“…In agreement with the findings of our study (19) on the predominantly myocardial effects of sugar-sweetened EDs are the following: 1) a report that the consumption of a sugarsweetened Monster ED (Monster Beverage; 2.0 mg caffeine/kg and 0.65 g sugar/kg) significantly elevated heart rate after 60 min compared with the placebo control (20), 2) a study in which blood pressure and heart rate responses to a sugarsweetened ED (Rockstar, Rockstar, Inc.; 240 mg caffeine and ;62 g sugar) resulted in significantly elevated blood pressure values (systolic blood pressure: +6.6 mm Hg; diastolic blood pressure: +4.2 mm Hg) compared with a sugarmatched placebo (21), and 3) findings from current studies evaluating the impact of sugar-free caffeinated energy shots [5-h Energy; 200 mg and 215 mg caffeine] on cardiovascular variables that showed that blood pressure variables significantly increased whereas heart rate did not change (22,23). Moreover, repeated intakes of an ED [8.3 oz of a Red Bull ED (Red Bull GmbH) 4 times over 24 h; 1 oz = 30 mL] increased blood pressure variables when compared with a water drink with equivalent amounts of caffeine (8 oz water with 80 mg caffeine) (24).…”

Impact of Acute Energy Drink Consumption on Blood Pressure Parameters

“…Expecting a possibly compensatory reduction in HR as a result of increased BP, the lowest available data point independent of time was extracted for the HR end point. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] When multiple usable arms were available within an individual study, the data were counted as another study in the meta-analysis model. 19 This was done in parallel design studies only to avoid artificial sample size inflation.…”