Effect Of Energy Drink Consumption On Heart Rate Variability And Blood Glucose In Relation To Exercise
METHODS: Consecutive 14 girl runners (16.6 0.7 y/o, 161.0 6.3 cm, 45.2 5.4 kg) in the same competitive high school team were evaluated without control on food and exercise. Each runner was asked to report dietary records with photos and training logs for 7 days. Energy intake (EI) was assessed by registered nutritionists. The runners were tested on treadmill with indirect calorimeter to yield individual prediction equations for VO2 by running velocity. Exercise energy expenditure (EEE) was calculated by the equations based on the training log. EA was calculated by subtracting EEE from EI for each day. The daily means of those variables were calculated. BMR was measured by whole room calorimeter in the early morning after overnight sleep at the night of the last day of the assessment inside the calorimeter. Body composition was measured by DXA. Bivariate correlation analyses and t test were used to examine the relationships and the difference between variables and groups, respectively. RESULTS: Percent body fat %BF) fat free mass (FFM) and bone mineral density of TBLH (BMD) were 13.3 4.5 39.0 3.5 kg, and 1.013 0.04 g/cm, respectively. BMR, EI, EEE, and EA were 26.5 2.4 kcal/kg*FFM/day, 2330 479 kcal/day, 892 245 kcal/day, and 37.4 10.7 kcal/kg*FFM/day, respectively. EA was significantly correlated with BMR (r=0.60, p=0.02) However, EA was not correlated with either %BF (p=0.25) or BMD (p=0.16) and did not differ between runners with oligo/amenorrhea (n=7; 40.8 11.9) and eumenorrhea (n=6; 34.0 9.8) (p=0.29) CONCLUSIONS: The strong linear correlation between EA and BMR supports the theory that decrease in EA leads to compensatory adaptation in metabolism which may suppress reproduction or bone mineral accrual. However, arbitrarily evaluated EA in short term was not related to the triad associated conditions. Those results were consistent with the evidences from adult Caucasian population.