Background: The purpose of this study was to examine the acute metabolic effects of a high-energy drink in healthy, physically-active women.
Methods: Ten women (20.4 +/- 0.70 y; 166.9 +/- 7.2 cm; 67.0 +/- 7.0 kg; 29.6 +/- 6.5% body fat) underwent two testing sessions administered in a randomized and double-blind fashion. Subjects reported to the laboratory in a 3-hr post-absorptive state and were provided either 140 ml of the high-energy drink (SUP; commercially marketed as Meltdown RTD) or placebo (P). Subjects consumed two 70 ml doses of SUP or P, separated by 30 min and rested in a semi-recumbent position for 3 hours. Resting oxygen consumption (VO2) and heart rate (HR) were determined every 5 min during the first 30 min and every 10 min during the next 150 min. Blood pressure (BP) was determined every 15 min during the first 30 min and every 30 min thereafter. Area under the curve (AUC) analysis was computed for VO2, whereas a 3-hour average and hourly averages were calculated for respiratory quotient (RQ), total kcal, HR, BP, and profile of mood states (POMS).
Results: AUC analysis revealed a 10.8% difference (p = 0.03) in VO2 between SUP and P. No difference in VO2 was seen between the groups in the first hour, but VO2 in SUP was significantly greater than P in the second (13.9%, p = 0.01) and third hours (11.9%, p = 0.03). A difference (p = 0.03) in energy expenditure was seen between SUP (1.09 +/- 0.10 kcal x min-1) and P (0.99 +/- 0.09 kcal x min-1) for the 3-hour period. Although no difference in energy expenditure was seen in the first hour, significant differences between SUP and P were observed in the second (1.10 +/- 0.11 kcal x min-1 and 0.99 +/- 0.09 kcal x min-1, respectively; p = 0.02) and third hour (1.08 +/- 0.11 kcal x min-1 and 0.99 +/- 0.09 kcal x min-1, respectively; p = 0.05). Average systolic BP was significantly higher (p = 0.007) for SUP (110.0 +/- 3.9 mmHg) compared to P (107.3 +/- 4.4 mmHg). No differences were seen in HR, diastolic BP, or POMS at any time point.
Conclusions: Results showed a significant increase in energy expenditure in young, healthy women following an acute ingestion of a high-energy drink.