HypertensionNCT07159152
Effects of Coffee Versus Hibiscus Tea Consumption During Prolonged Sitting on Blood Pressure and Heart Rate
A study testing Coffee and Hibiscus drink in people with Hypertension, run by King Saud University at 1 site in Saudi Arabia.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Hypertension
- What is being tested?
- Coffee and Hibiscus drink
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteSaudi Arabia
- Study dates
- 1 Sep 2025to 1 Mar 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Saudi Arabia1 site
Princess Nourah University Lifestyle Center
Riyadh, 80200
Mohanad S AlJubairi, MSc, +966553899006, MSAljabiri@pnu.edu.sa
About this study
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.
Read more
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.
Read the 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.
- Conditions
- Hypertension
- Being tested
- Coffee, Hibiscus drink
- Keywords
- hibiscus drink, coffee, prolonged sitting, sedentary behavior, cardiovascular health, vascular function, cardiovascular regulation
- Medical subject headings
- Hypertension, Sedentary Behavior
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CoffeeDietary supplement
Participants will consume 3 cups of Arabica coffee (Guatemalan origin), providing a total of 400 mg of caffeine. Each cup is prepared with 6% coffee grounds per 100 mL of water, brewed at 90°C for 6 minutes using an electric drip coffee maker, yielding 100.8 mg caffeine per 100 mL. Immediately following coffee consumption, participants will engage in uninterrupted sitting for 3 hours. Blood pressure, heart rate, and other study questionnaires will be measured at baseline (before coffee), 1 hour after coffee intake, and hourly during the 3-hour sitting period.
Hibiscus drinkDietary supplement
Participants will consume 3 servings of hibiscus leaves tea per day, each serving containing 1.25 g of dried hibiscus leaves, totaling 3.75 g per session. The tea will be prepared by steeping the leaves in 240 mL of boiling water (100°C) for 10 minutes. Immediately after consuming the hibiscus tea, participants will engage in uninterrupted sitting for 3 hours. Blood pressure, heart rate, and other study questionnaires will be measured at baseline (before tea), 1 hour after tea intake, and hourly during the 3-hour sitting.
| Study group | Role | What they receive |
|---|---|---|
| Coffee plus prolonged sitting protocol | Experimental | all participants in this group follow the coffee protocol Receives: Dietary Supplement: Coffee |
| Hibiscus drink plus prolonged sitting protocol | Experimental | all participants in this group follow the hibiscus drink protocol Receives: Dietary Supplement: Hibiscus drink |
What is being measured
The primary outcome is the main question the study is designed to answer.
Systolic and diastolic blood pressure
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).
Measured: 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.
Heart Rate
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)
Measured: 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.
NN Intervals
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)
Measured: 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.
RMSSD
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)
Measured: 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.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Sep 2025
- Study start1 Sep 2025 (estimated)
- Primary completion1 Feb 2026 (estimated)
- Study completion1 Mar 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (14)Papers the sponsor has linked to this study.
- Other trials for HypertensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- A randomized crossover design
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- King Saud University
- Sponsor type
- University, hospital or other
- Collaborators
- Princess Nourah Bint Abdulrahman University
- Responsible party
- Principal investigator, Abdullah Bandar Alansare, King Saud University
- Investigators
- Hadeel M Almalki, BSc, Principal investigator, Princess Nourah Bint Abdulrahman University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07159152
- Sponsor's protocol ID
- No. E-25-9503
- Status last verified
- Aug 2025
- First submitted
- 23 Aug 2025
- Last updated
- 8 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared outside the research team due to restrictions in the informed consent provided by participants
Publications
Abdelmonem M, Ebada MA, Diab S, Ahmed MM, Zaazouee MS, Essa TM, ElBaz ZS, Ghaith HS, Abdella WS, Ebada M, Negida A. Efficacy of Hibiscus sabdariffa on Reducing Blood Pressure in Patients With Mild-to-Moderate Hypertension: A Systematic Review and Meta-Analysis of Published Randomized Controlled Trials. J Cardiovasc Pharmacol. 2022 Jan 1;79(1):e64-e74. doi: 10.1097/FJC.0000000000001161.
PubMed 34694241Ellis LR, Zulfiqar S, Holmes M, Marshall L, Dye L, Boesch C. A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers. Nutr Rev. 2022 May 9;80(6):1723-1737. doi: 10.1093/nutrit/nuab104.
PubMed 34927694Da-Costa-Rocha I, Bonnlaender B, Sievers H, Pischel I, Heinrich M. Hibiscus sabdariffa L. - a phytochemical and pharmacological review. Food Chem. 2014 Dec 15;165:424-43. doi: 10.1016/j.foodchem.2014.05.002. Epub 2014 May 27.
PubMed 25038696Sindi HA, Marshall LJ, Morgan MR. Comparative chemical and biochemical analysis of extracts of Hibiscus sabdariffa. Food Chem. 2014 Dec 1;164:23-9. doi: 10.1016/j.foodchem.2014.04.097. Epub 2014 May 6.
PubMed 24996300Nohara-Shitama Y, Adachi H, Enomoto M, Fukami A, Nakamura S, Kono S, Morikawa N, Sakaue A, Hamamura H, Toyomasu K, Fukumoto Y. Habitual coffee intake reduces all-cause mortality by decreasing heart rate. Heart Vessels. 2019 Nov;34(11):1823-1829. doi: 10.1007/s00380-019-01422-0. Epub 2019 May 6.
PubMed 31062117Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr. 1999 Nov;53(11):831-9. doi: 10.1038/sj.ejcn.1600899.
PubMed 10556993Alfawaz HA, Khan N, Yakout SM, Khattak MNK, Alsaikhan AA, Almousa AA, Alsuwailem TA, Almjlad TM, Alamri NA, Alshammari SG, Al-Daghri NM. Prevalence, Predictors, and Awareness of Coffee Consumption and Its Trend among Saudi Female Students. Int J Environ Res Public Health. 2020 Sep 25;17(19):7020. doi: 10.3390/ijerph17197020.
PubMed 32992846Rao NZ, Fuller M, Grim MD. Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry: The Effects of Roast Level and Brewing Temperature on Compound Extraction. Foods. 2020 Jul 9;9(7):902. doi: 10.3390/foods9070902.
PubMed 32659894Hecimovic I, Belscak-Cvitanovic A, Horzic D, Komes D. Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting. Food Chem. 2011 Dec 1;129(3):991-1000. doi: 10.1016/j.foodchem.2011.05.059. Epub 2011 May 15.
PubMed 25212328Paterson C, Fryer S, Zieff G, Stone K, Credeur DP, Barone Gibbs B, Padilla J, Parker JK, Stoner L. The Effects of Acute Exposure to Prolonged Sitting, With and Without Interruption, on Vascular Function Among Adults: A Meta-analysis. Sports Med. 2020 Nov;50(11):1929-1942. doi: 10.1007/s40279-020-01325-5.
PubMed 32757163Taylor FC, Pinto AJ, Maniar N, Dunstan DW, Green DJ. The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis. Med Sci Sports Exerc. 2022 Jan 1;54(1):67-76. doi: 10.1249/MSS.0000000000002763.
PubMed 34334722Vranish JR, Young BE, Kaur J, Patik JC, Padilla J, Fadel PJ. Influence of sex on microvascular and macrovascular responses to prolonged sitting. Am J Physiol Heart Circ Physiol. 2017 Apr 1;312(4):H800-H805. doi: 10.1152/ajpheart.00823.2016. Epub 2017 Jan 27.
PubMed 28130340Dempsey PC, Larsen RN, Dunstan DW, Owen N, Kingwell BA. Sitting Less and Moving More: Implications for Hypertension. Hypertension. 2018 Nov;72(5):1037-1046. doi: 10.1161/HYPERTENSIONAHA.118.11190. No abstract available.
PubMed 30354827Adams NT, Paterson C, Poles J, Higgins S, Stoner L. The Effect of Sitting Duration on Peripheral Blood Pressure Responses to Prolonged Sitting, With and Without Interruption: A Systematic Review and Meta-Analysis. Sports Med. 2024 Jan;54(1):169-183. doi: 10.1007/s40279-023-01915-z. Epub 2023 Sep 8.
PubMed 37682412
Study at a glance
From the registry record, last updated by the sponsor on 8 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Coffee Versus Hibiscus Tea Consumption During Prolonged Sitting on Blood Pressure and Heart Rate
- ClinicalTrials.gov ID
- NCT07159152
- Acronym / sponsor ID
- No. E-25-9503
- Conditions
- Hypertension
- Keywords
- hibiscus drink, coffee, prolonged sitting, sedentary behavior, cardiovascular health, vascular function, cardiovascular regulation
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- King Saud UniversityUniversity, hospital or other
- Collaborators
- Princess Nourah Bint Abdulrahman University
- Study start
- 1 Sep 2025 (estimated)
- Primary completion
- 1 Feb 2026 (estimated)
- Study completion
- 1 Mar 2026 (estimated)
- First posted
- 8 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- A randomized crossover design
| Arm | Type | Receives |
|---|---|---|
| Coffee plus prolonged sitting protocol | Experimental | Dietary Supplement: Coffeeall participants in this group follow the coffee protocol |
| Hibiscus drink plus prolonged sitting protocol | Experimental | Dietary Supplement: Hibiscus drinkall participants in this group follow the hibiscus drink protocol |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (3 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CoffeeParticipants will consume 3 cups of Arabica coffee (Guatemalan origin), providing a total of 400 mg of caffeine. Each cup is prepared with 6% coffee grounds per 100 mL of water, brewed at 90°C for 6 minutes using an electric drip coffee maker, yielding 100.8 mg caffeine per 100 mL. Immediately following coffee consumption, participants will engage in uninterrupted sitting for 3 hours. Blood pressure, heart rate, and other study questionnaires will be measured at baseline (before coffee), 1 hour after coffee intake, and hourly during the 3-hour sitting period. | Dietary supplement | Coffee plus prolonged sitting protocol |
| Hibiscus drinkParticipants will consume 3 servings of hibiscus leaves tea per day, each serving containing 1.25 g of dried hibiscus leaves, totaling 3.75 g per session. The tea will be prepared by steeping the leaves in 240 mL of boiling water (100°C) for 10 minutes. Immediately after consuming the hibiscus tea, participants will engage in uninterrupted sitting for 3 hours. Blood pressure, heart rate, and other study questionnaires will be measured at baseline (before tea), 1 hour after tea intake, and hourly during the 3-hour sitting. | Dietary supplement | Hibiscus drink plus prolonged sitting protocol |
Primary outcome
Systolic and diastolic blood pressure
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Sep 2025.
- Results publication: PubMed 34694241Abdelmonem M, Ebada MA, Diab S, Ahmed MM, Zaazouee MS, Essa TM, ElBaz ZS, Ghaith HS, Abdella WS, Ebada M, Negida A. Efficacy of Hibiscus sabdariffa on Reducing Blood Pressure in Patients With Mild-to-Moderate Hypertension: A Systematic Review and Meta-Analysis of Published Randomized Controlled Trials. J Cardiovasc Pharmacol. 2022 Jan 1;79(1):e64-e74. doi: 10.1097/FJC.0000000000001161.
- Results publication: PubMed 34927694Ellis LR, Zulfiqar S, Holmes M, Marshall L, Dye L, Boesch C. A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers. Nutr Rev. 2022 May 9;80(6):1723-1737. doi: 10.1093/nutrit/nuab104.
- Results publication: PubMed 25038696Da-Costa-Rocha I, Bonnlaender B, Sievers H, Pischel I, Heinrich M. Hibiscus sabdariffa L. - a phytochemical and pharmacological review. Food Chem. 2014 Dec 15;165:424-43. doi: 10.1016/j.foodchem.2014.05.002. Epub 2014 May 27.
- Results publication: PubMed 24996300Sindi HA, Marshall LJ, Morgan MR. Comparative chemical and biochemical analysis of extracts of Hibiscus sabdariffa. Food Chem. 2014 Dec 1;164:23-9. doi: 10.1016/j.foodchem.2014.04.097. Epub 2014 May 6.
- Results publication: PubMed 31062117Nohara-Shitama Y, Adachi H, Enomoto M, Fukami A, Nakamura S, Kono S, Morikawa N, Sakaue A, Hamamura H, Toyomasu K, Fukumoto Y. Habitual coffee intake reduces all-cause mortality by decreasing heart rate. Heart Vessels. 2019 Nov;34(11):1823-1829. doi: 10.1007/s00380-019-01422-0. Epub 2019 May 6.
- Results publication: PubMed 10556993Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr. 1999 Nov;53(11):831-9. doi: 10.1038/sj.ejcn.1600899.
- Results publication: PubMed 32992846Alfawaz HA, Khan N, Yakout SM, Khattak MNK, Alsaikhan AA, Almousa AA, Alsuwailem TA, Almjlad TM, Alamri NA, Alshammari SG, Al-Daghri NM. Prevalence, Predictors, and Awareness of Coffee Consumption and Its Trend among Saudi Female Students. Int J Environ Res Public Health. 2020 Sep 25;17(19):7020. doi: 10.3390/ijerph17197020.
- Results publication: PubMed 32659894Rao NZ, Fuller M, Grim MD. Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry: The Effects of Roast Level and Brewing Temperature on Compound Extraction. Foods. 2020 Jul 9;9(7):902. doi: 10.3390/foods9070902.
- Results publication: PubMed 25212328Hecimovic I, Belscak-Cvitanovic A, Horzic D, Komes D. Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting. Food Chem. 2011 Dec 1;129(3):991-1000. doi: 10.1016/j.foodchem.2011.05.059. Epub 2011 May 15.
- Results publication: PubMed 32757163Paterson C, Fryer S, Zieff G, Stone K, Credeur DP, Barone Gibbs B, Padilla J, Parker JK, Stoner L. The Effects of Acute Exposure to Prolonged Sitting, With and Without Interruption, on Vascular Function Among Adults: A Meta-analysis. Sports Med. 2020 Nov;50(11):1929-1942. doi: 10.1007/s40279-020-01325-5.
- Results publication: PubMed 34334722Taylor FC, Pinto AJ, Maniar N, Dunstan DW, Green DJ. The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis. Med Sci Sports Exerc. 2022 Jan 1;54(1):67-76. doi: 10.1249/MSS.0000000000002763.
- Results publication: PubMed 28130340Vranish JR, Young BE, Kaur J, Patik JC, Padilla J, Fadel PJ. Influence of sex on microvascular and macrovascular responses to prolonged sitting. Am J Physiol Heart Circ Physiol. 2017 Apr 1;312(4):H800-H805. doi: 10.1152/ajpheart.00823.2016. Epub 2017 Jan 27.
- Individual participant dataSharing planned: No. Individual participant data will not be shared outside the research team due to restrictions in the informed consent provided by participants
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Hadeel M Almalki, BSc principal investigator
Princess Nourah Bint Abdulrahman University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Coffee and Hibiscus drink in people with Hypertension, run by King Saud University at 1 site in Saudi Arabia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 8 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Saudi Arabia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Abdullah B Alansare, PhD (+966555061381, aalansare@ksu.edu.sa), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Systolic and diastolic blood pressure (time frame: 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.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07159152, which also lists 14 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Sep 2025.