Synergistic effect of energy drinks and overweight/obesity on cardiac autonomic testing using the Valsalva maneuver in university students

BACKGROUND: Obesity and caffeine consumption may lead to autonomic disturbances that can result in a wide range of cardiovascular disorders. OBJECTIVES: To determine autonomic disturbances produced by the synergistic effects of overweight or obesity (OW/OB) and energy drinks. DESIGN: Cross-sectional, analytical. SETTING: Physiology department at a university in Saudi Arabia. SUBJECTS AND METHODS: University students, 18-22 years of age, of normal weight (NW) and OW/OB were recruited by convenience sampling. Autonomic testing by the Valsalva ratio (VR) along with systolic and diastolic blood pressure, pulse pressure, and mean arterial blood pressure were measured at baseline (0 minute) and 60 minutes after energy drink consumption. MAIN OUTCOME MEASURE(S): Autonomic disturbance, hemodynamic changes. RESULTS: In 50 (27 males and 23 females) subjects, 21 NW and 29 OW/OB, a significant decrease in VR was observed in OW/OB subjects and in NW and OW/OB females at 60 minutes after energy drink consumption. Values of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure were also significantly higher in OW/OB and in females as compared to NW and males. BMI was negatively correlated with VR and diastolic blood pressure at 60 minutes. CONCLUSION: Obesity and energy drinks alter autonomic functions. In some individuals, OW/OB may augment these effects. LIMITATIONS: Due to time and resource restraints, only the acute effects of energy drinks were examined.