Acute Effects of Energy Drink on Hemodynamic and Electrophysiologic Parameters in Habitual and Non-Habitual Caffeine Consumers

In this study, it is aimed to determine the acute effects of energy drink on habitual and non-habitual caffeine consumers and if caffeine consumption habit causes a difference on the hemodynamic and electrophysiologic parameters. In this respect, the complicated human body's reactions to these beverages will be examined in more detail.

Materials and methods Participants Forty eight participants (16 female, 32 male) aged 18-24 were selected from the students which are in the first year of various faculties of Aydın Adnan Menderes University. The individuals were identified by collecting the age, weight, height, BMI, caffeine and energy drink consumption habit information by applicant acceptance questionnaire. According to the results of applicant acceptance questionnaire, those with a body mass index greater than 30 kg/m2, a systemic disease, current alcoholism and smokers were not included in the study. Also, the participants who has previous adverse reactions to energy drinks were excluded to prevent undesired reactions associated with this condition. Based on the applicant acceptance questionnaire 12 subjects were low-habitual caffeine consumers with an estimated daily intake of approximately 130 mg caffeine and named as energy drink 2 (ED2) group, 12 subjects were high-habitual caffeine consumers with an estimated daily intake of approximately more than 200 mg caffeine and named as energy drink 3 (ED3) group, while 24 subjects were caffeine naive (energy drink 1 (ED1) (n=12) and Control (n=12)) . This study conforms to the Declaration of Helsinki and was approved by the Institutional Medical Ethics Committee of Adnan Menderes University (Protocol number: 2017/1211).

Experimental protocol All experiments were performed in a quiet and isolated room from external factors with room temperature of about 20°C and relative humidity between %40 and 60. All participants were advised to avoid alcohol and caffeine containing foods for at least 72 h prior to the test and to come with an overnight (12 h) fasting.

Blood pressure, electrocardiogram, breath rate, haemoglobin oxygen saturation (HOS) and BIA measurements were performed from the participants before the consumption of drinks. After the measurements ED1, ED2 and ED3 groups consumed 473 ml of Red Bull energy drink containing 151.36 mg caffeine and control group consumed the same amount of water within 5 minutes. The measurements were performed again in 30 minutes and 60 minutes. Also, state-trait anxiety inventory test (STAI) was used to assess the physiological stress of the participants.

Blood Pressure Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured indirectly by using a stethoscope (Littman Classic II, Saint Paul, USA) and aneroid sphygmomanometer (Welch Allyn Tycos, New York, USA) on each participant left arm in sitting position.