The purpose of this study will be to examine the acute effect of commercially available energy products on endothelial function, arterial stiffness and thrombosis in healthy young males.

The use of energy products has significantly increased in the last few years and is especially high among young men. The present study will compare the acute effect of a commercially available energy drink, energy gum, coffee and control beverage on endothelial function, arterial stiffness and circulating markers of thrombosis, inflammation and oxidative stress.

Inclusion Criteria:

• Being Male
• 18-30 years of age
• No indication of major clinical disease (e.g. diabetes, hypertension, significant arrhythmias, syncope and cardiovascular disease)
• BMI ≤ 30 kg/m^2 and blood pressure ≤ 140/90 mmHg
• Consumption of <400mg of caffeine/day
• Prior history of consumption of energy drinks

Exclusion criteria:

• Being female
• Age <18 or >30 years
• BMI> 30 kg/m^2 and blood pressure > 140/90 mmHg
• Use of medication that may affect vascular measures
• Use of tobacco products including smoking
• Vegan or vegetarian diet
• Being energy drink or caffeine naïve or consumption of >400 mg of caffeine/day
• Consumption of >1 energy drinks per month
• Being a shift worker