Effects of Coffee Versus Hibiscus Tea Consumption During Prolonged Sitting on Blood Pressure and Heart Rate

Not Applicable

Not yet recruiting

• Conditions: Hypertension

• Registration Number: NCT07159152
• Lead Sponsor: King Saud University

Brief Summary

Modern lifestyles often involve long periods of sitting, which can increase the risk of heart problems, obesity, and other health issues. Diet also plays a key role in heart health. Coffee and hibiscus tea are two common beverages, but their effects during prolonged sitting are not well understood.

This study will examine how drinking coffee versus hibiscus tea affects blood pressure, heart rate, and heart rate variability in men and women during extended periods of sitting.

Participants (30 in total: 15 women and 15 men) will take part in a randomized crossover study, meaning each person will try both beverages at different times. Data will be collected using questionnaires, body measurements, and devices to measure heart rate, blood pressure, and heart rate variability.

The goal is to better understand how these drinks influence heart health during sedentary behavior.

Detailed Description

Modern lifestyles, shaped by technological advancements and urbanization, have led to a dramatic increase in sedentary behavior, particularly prolonged sitting. Physical inactivity is a major risk factor for cardiovascular diseases (CVDs), obesity, and premature mortality, with women generally being less active than men. Prolonged sitting affects key indicators of cardiovascular health, including blood pressure, heart rate, and heart rate variability (HRV), which reflect autonomic nervous system regulation and overall heart function. Despite the growing concern, research on how sedentary behavior specifically affects women, particularly in Saudi Arabia, remains limited.

Dietary habits also play a critical role in cardiovascular health. Coffee, one of the most widely consumed beverages worldwide, contains caffeine and polyphenols that can both stimulate and protect the cardiovascular system. Moderate coffee consumption may provide benefits such as reduced risk of chronic diseases and lower resting heart rate, while excessive intake can increase blood pressure, particularly in hypertensive individuals. Hibiscus tea, rich in flavonoids and antioxidants like anthocyanins, has been traditionally used as an antihypertensive agent. It has potential therapeutic effects, including lowering blood pressure, improving metabolic health, and protecting against cardiovascular inflammation. However, the acute effects of these beverages during prolonged sitting are not well understood.

This study aims to investigate the effects of coffee versus hibiscus tea on blood pressure, heart rate, and HRV in healthy women during extended periods of sitting. Using a randomized crossover design, participants will consume each beverage at separate times while their cardiovascular responses are monitored. Data will be collected through questionnaires, body composition measurements, and non-invasive devices to track blood pressure and heart rate variability. By comparing the acute effects of coffee and hibiscus tea during sedentary behavior, this study seeks to provide new insights into how common dietary choices may influence cardiovascular function and help guide recommendations for healthier lifestyles in populations at risk of prolonged sitting.

Study Timeline

• Status Verified: 2025-08
• Study First Submitted: 2025-08-23
• Study First Submitted QC: 2025-08-28
• Last Update Submitted: 2025-08-28
• Study Start: 2025-09-01
• Study First Posted: 2025-09-08
• Last Update Posted: 2025-09-08
• Primary Completion: 2026-02-01
• Study Completion: 2026-03-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Age between 18 and 35 years.
• Normal to elevated blood pressure (systolic <130 mmHg and diastolic <80 mmHg) and normal resting heart rate (60-100 bpm), ensuring selection of healthy adults and minimizing confounding factors.
• Generally healthy, without chronic or acute medical conditions, to reduce external influences on study outcomes.
• Physically inactive, not meeting current physical activity guidelines, as the study targets sedentary individuals.

Exclusion Criteria

• Known allergy or hypersensitivity to hibiscus or coffee, as participants will consume these beverages during the study.
• Current use of medications that could influence blood pressure, heart rate, or heart rate variability, including antihypertensive, chronotropic, or vasoactive drugs.
• Any medical condition or health issue that may interfere with safe participation or affect study measurements.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Systolic and diastolic blood pressure	Blood pressure will be recorded at five standardized time points: prior to consumption of coffee or hibiscus tea, one hour post-consumption, and following one, two, and three hours of prolonged sitting.	Systolic and diastolic blood pressure will be assessed using an oscillometric blood pressure monitor (Omron HEM 7124 CP, Omron Healthcare, Illinois, USA). Measurements will be conducted in accordance with the guidelines of the American Heart Association (AHA) and the American College of Cardiology (ACC).
Heart Rate	Heart rate measurements will be performed at multiple time points during each visit: prior to beverage consumption, one hour post-consumption, and after one, two, and three hours of prolonged sitting.	Heart rate will be measured using the Polar V800 system, which consists of a wristwatch and a Bluetooth heart rate sensor. The sensor will be positioned on the participant's chest, just below the pectoral muscles. Participants will remain seated quietly for 10 minutes while continuous heart rate data are recorded according to the manufacturer's instructions.; The clearest five-minute segment of the 10-minute recording will be analyzed using Kubios HRV Premium software to assess heart rate (beat/minute)
NN Intervals	NN Intervals measurements will be performed at multiple time points during each visit: prior to beverage consumption, one hour post-consumption, and after one, two, and three hours of prolonged sitting.	NN Intervals will be measured using the Polar V800 system, which consists of a wristwatch and a Bluetooth heart rate sensor. The sensor will be positioned on the participant's chest, just below the pectoral muscles. Participants will remain seated quietly for 10 minutes while continuous heart rate data are recorded according to the manufacturer's instructions.; The clearest five-minute segment of the 10-minute recording will be analyzed using Kubios HRV Premium software to assess NN Intervals (milliseconds)
RMSSD	RMSSD measurements will be performed at multiple time points during each visit: prior to beverage consumption, one hour post-consumption, and after one, two, and three hours of prolonged sitting.	RMSSD will be measured using the Polar V800 system, which consists of a wristwatch and a Bluetooth heart rate sensor. The sensor will be positioned on the participant's chest, just below the pectoral muscles. Participants will remain seated quietly for 10 minutes while continuous heart rate data are recorded according to the manufacturer's instructions.; The clearest five-minute segment of the 10-minute recording will be analyzed using Kubios HRV Premium software to assess RMSSD (milliseconds squared)

Trial Locations

Locations (1)

Princess Nourah University Lifestyle Center; 🇸🇦 Riyadh, Saudi Arabia