This randomized controlled crossover trial investigates the acute effects of consuming dark, milk, and white chocolate before prolonged sitting on cardiovascular health in healthy adults. Each participant completes three separate study visits and receives all three chocolate conditions in a randomized order, with a 7-day washout period between visits. Blood pressure, heart rate, pulse wave velocity, blood glucose, appetite, pain, and calf circumference are measured before and during a 3-hour sitting perio

Prolonged sitting is associated with acute adverse changes in vascular and metabolic health. Cocoa-rich chocolate contains bioactive compounds that may influence vascular responses; however, the effects of different chocolate types consumed before prolonged sitting are not fully understood.

This study is a randomized controlled crossover trial in healthy adults. Each participant completes three experimental visits and receives all three chocolate conditions (dark chocolate, milk chocolate, and white chocolate) in a randomized sequence determined before enrollment. A 7-day washout period is maintained between visits to minimize carryover effects.

At each visit, baseline measurements are obtained before chocolate consumption. Participants then consume the assigned chocolate condition, followed by post-consumption assessments and a standardized 3-hour sitting period. Repeated measurements are collected throughout the sitting period.

Outcome measures include blood pressure, heart rate, pulse wave velocity, capillary blood glucose, appetite visual analogue scale(VAS), pain visual analogue scale(VAS), and calf circumference. The study aims to compare acute physiological responses among the three chocolate conditions before prolonged sitting.

Inclusion Criteria:

• Adult males and females aged between 18 and 40 years.
• Participants with blood pressure within the normal or elevated range (less than 130/80 mmHg), according to the American Heart Association guidelines.

Exclusion Criteria:

• Females with menopause will be excluded due to the physiological effects of menopause and to ensure hormonal stability.
• Participants with nut allergies, due to the possibility that the chocolate used may contain traces of nuts resulting from manufacturing processes.
• Participants with dairy allergies, due to the use of milk chocolate and white chocolate, and the possibility that dark chocolate may contain traces of milk resulting from manufacturing processes .
• Participants with chronic diseases that may affect the study variables, such as cardiovascular diseases, respiratory diseases, diabetes, or any medical condition that affects circulation.
• Participants using medications that may affect the targeted physiological measurements in the study, such as antihypertensive medications, antidiabetic medications, or drugs affecting the autonomic nervous system.
• Participants with a body mass index (BMI) ≥ 30 kg/m², due to the association between obesity and vascular dysfunction, characterized by increased blood pressure and arterial stiffness, which may lead to variability in vascular responses.
• Participants who are physically active (≥150 minutes per week of moderate-to-vigorous physical activity), to avoid the impact of high levels of training on vascular responses.
• Smokers, due to the chronic effects of smoking on endothelial function and arterial stiffness.
• Participants with back injuries that limit their ability to sit continuously for three hours.
• Female participants who are pregnant, breastfeeding, due to the associated hormonal changes that may influence the physiological indicators measured in the study.

Data sharing plans have not yet been finalized and will be determined after study completion in consultation with the investigators and institutional policies.