HealthyNCT07265869
Can Cocoa Flavanols Protect Endothelial Function During Prolonged Sitting in Healthy Older Adults?
A study testing High-flavanol cocoa powder and Low-flavanol cocoa powder in people with Healthy and Ageing, run by University of Birmingham at 1 site in United Kingdom.
Trial summary
Sitting time is high in older adults and has been shown to temporarily impair endothelial function and blood pressure. Flavanols, plant-derived compounds, acutely enhance endothelial function and reduce Blood pressure in older adults. Read more about this study
- Who is it for?
- Ages 65 years and olderHealthy volunteers can take part
- What is being tested?
- High-flavanol cocoa powder and Low-flavanol cocoa powder
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 20 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 2 Aug 2022to 24 Aug 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 65 years and older
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- Males and females
- aged 65 or more
Who cannot join
- history or symptoms of cardiovascular, renal, pulmonary, metabolic, or neurologic disease, hypertension (blood pressure higher than 140/90 mm Hg, based on recent guidelines), diabetes mellitus, anaemia, asthma, immune conditions, or high cholesterol.
- smoker
- individuals who were on weight-reducing diets
- individuals taking anticoagulants,
- had recently undergone prolonged bed-rest periods
- have been on antibiotics in the previous 3 months
- have an infection at present (e.g. cold) or viral infection
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham
Birmingham, West Midlands, B15 2TT
About this study
Official title: A Placebo-controlled, Randomized, Double-masked, Cross-over Acute Intervention Study Investigating the Effects of Cocoa Flavanols on Peripheral Endothelial Function in the Context of Prolonged Sitting in Healthy Older Adults
Sitting time is high in older adults and has been shown to temporarily impair endothelial function and blood pressure. Flavanols, plant-derived compounds, acutely enhance endothelial function and reduce Blood pressure in older adults. The aim of this study is to investigate whether acute ingestion of cocoa flavanols can improve peripheral endothelial function and blood pressure during prolonged sitting in healthy older adults.
In a randomised, double-blinded, cross-over, placebo-controlled human study, 20 healthy older adults will consume either a high-flavanol (695 mg) or low-flavanol (5.6 mg) cocoa beverage immediately before a 2-hour sitting bout. Flow-mediated dilation (FMD) of the superficial femoral (SFA; primary outcome) and brachial (BA) arteries, and blood pressure, were assessed before and after sitting. Microvasculature haemodynamics were assessed in the gastrocnemius before, during, and after sitting. It is hypothesized that the high flavanol cocoa will prevent declines in brachial and superficial femoral Flow-mediated dilatation post sitting.
Read the detailed description
Older individuals are estimated to spend more than 10 hours in their waking day in sedentary activities , which can include sitting bouts lasting up to 5.4 hours/day . Greater sedentary time was found to be associated with a significantly increased risk of cardiovascular diseases and all-cause mortality. Several experimental studies have shown that even just one isolated episode of prolonged sitting (from 1 to 6 hours) has detrimental effects on human endothelial function, as measured by flow-mediated dilation (FMD).
Flavonoid-rich foods are typically consumed in high amounts in cardioprotective diets, with evidence from both observational and Randomised Controlled Trials showing flavonoids to improve biomarkers of cardiovascular health. Flavanols, a sub-group of flavonoids present in unprocessed cocoa, have been extensively shown to act quickly within the vasculature, improving both brachial Flow-mediated dilatation and lower-limb common femoral artery (CFA) Flow-mediated dilatation within 2 hours of intake in older adults.
The aim of the current study is to examine whether acute consumption of cocoa flavanols prior to a 2-hour bout of uninterrupted sitting can be beneficial in improving endothelial function (as measured by Flow mediated dilatation) in the upper-limb Brachial Artery (BA) and lower-limb Superficial Femoral Artery (SFA) in older adults, as well as downstream, muscle microvascular function. We will further investigate whether cocoa flavanols can prevent sitting-induced increases in blood pressure in older adults. We hypothesise that cocoa flavanols would be effective at rescuing upper- and lower-limb Flow-mediated dilatation and improve blood pressure during uninterrupted sitting in older age
- Being tested
- High-flavanol cocoa powder, Low-flavanol cocoa powder
- Keywords
- vascular function, endothelial function, flow-mediated dilatation, flavanols, cocoa, flavonoids, polyphenols, sitting, sedentary, ageing, older adults, functional Near-Infrared Spectroscopy
- Medical subject headings
- Sedentary Behavior
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-flavanol cocoa powderDietary supplement
12 g of a fat-reduced natural cocoa powder containing 150 mg of (-)-epicatechin, and 695 mg of total flavanols
Low-flavanol cocoa powderDietary supplement
12 g of a fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols
| Study group | Role | What they receive |
|---|---|---|
| High-flavanol cocoa powder | Experimental | 12 g of fat-reduced natural cocoa powder containing 695 mg of total flavanols, including 150 mg (-)-epicatechin Receives: Dietary Supplement: High-flavanol cocoa powder |
| Low-flavanol cocoa powder | Placebo comparator | 12 g of fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols Receives: Dietary Supplement: Low-flavanol cocoa powder |
What is being measured
The primary outcome is the main question the study is designed to answer.
Flow-mediated dilatation of the superficial femoral artery
Flow-mediated dilatation (FMD) of the superficial femoral artery. Expressed as percent FMD: change in brachial diameter from baseline to peak dilation following 5 minutes of arterial occlusion. Brachial artery diameter and blood flow will be measured using Doppler ultrasonography (uSmart 3300, Terason).
Measured: Change from pre-intervention baseline to 2 hours post intervention /2 hours post sitting
Secondary outcomes (12)
Flow-mediated dilatation of the brachial artery
Flow-mediated dilatation (FMD) of the brachial artery. Expressed as percent FMD: change in brachial diameter from baseline to peak dilation following 5 minutes of arterial occlusion. Brachial artery diameter and blood flow will be measured using Doppler ultrasonography (uSmart 3300, Terason).
Measured: Change from pre-intervention baseline to 2 hours post-intervention/ 2hours post sitting
Tissue oxygenation index (TOI) of Gastrocnemius skeletal muscle
Tissue Oxygenation Index (percent TOI) will be assessed by functional Near-Infrared Spectroscopy (fNIRS) on the medial head of the gastrocnemius muscle during 5 min of superficial femoral arterial occlusion and 5 min of post-occlusion (reactive hyperaemia). The NIRS device measures changes in chromophore concentrations of oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb), providing depth-resolved measures of total tissue oxygen saturation.
Measured: Change from pre-intervention baseline to 2 hours post-intervention / 2 hours of sitting
Normalized haemoglobin index (nTHI) of the gastrocnemius skeletal muscle
Normalized haemoglobin index (relative value of total haemoglobin normalised to the initial value, nTHI) content (a.u.) will be assessed by functional Near-Infrared Spectroscopy (fNIRS) on the medial head of the gastrocnemius muscle during 5 minutes of superficial femoral arterial occlusion and 5 minutes of post-occlusion (reactive hyperaemia).
Measured: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Tissue oxygenation index (TOI) of Gastrocnemius skeletal muscle during 2 hours of sitting
Tissue Oxygenation Index (percent TOI) will be assessed by functional Near-Infrared Spectroscopy (fNIRS) on the medial head of the gastrocnemius muscle continuously during 2 hours of sitting. The NIRS device measures changes in chromophore concentrations of oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb), providing depth-resolved measures of total tissue oxygen saturation. Post-intervention time points considered during sitting were 0 minutes , 10 minutes, 60 minutes, and 120 minutes. For each time point, data were averaged over a 60-second period.
Measured: Post-intervention time points considered during sitting were 0 , 10 , 60 and 120 minutes.
Normalized haemoglobin index (nTHI) of Gastrocnemius skeletal muscle during 2 hours of sitting
Normalized haemoglobin index (relative value of total haemoglobin normalised to the initial value, nTHI) content (a.u.) will be assessed by functional Near-Infrared Spectroscopy (fNIRS) on the medial head of the gastrocnemius muscle continuously during 2 hours of sitting. Post-intervention time points considered during sitting were 0 min , 10 min, 60 min, and 120 min. For each time point, data were averaged over a 60-second period.
Measured: Post-intervention time points considered during sitting were 0 min , 10 min, 60 min and 120 min.
Brachial Systolic Blood Pressure (SBP)
Resting systolic blood pressure (mmHg) will be measured using an automated oscillometric blood pressure monitor, with a cuff attached to the right upper arm, following at least 10 minutes rest.
Measured: Change from pre-intervention baseline to 2 hours post-intervention / 2 hours of sitting
Brachial Diastolic Blood Pressure (DBP)
Resting diastolic blood pressure (mmHg) will be measured using an automated oscillometric blood pressure monitor, with a cuff attached to the right upper arm, following at least 10 minutes rest.
Measured: Change from pre-intervention baseline to 2 hours post-intervention / 2 hours of sitting
Heart Rate
Resting Heart Rate (beats per minute) will be measured using an automated oscillometric blood pressure monitor, with a cuff attached to the right upper arm, following at least 10 minutes rest.
Measured: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Resting Superficial Femoral Artery Blood Flow
Superficial Femoral Artery Blood Flow velocity (ml min-1) will be measured using Doppler ultrasonography (uSmart 3300, Terason) interfaced with the Quipu analysis software. Superficial femoral artery blood flow is calculated using Superficial femoral artery blood velocity and diameter during 1 minute of recording in a resting state
Measured: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Resting Brachial Artery Blood Flow
Resting Brachial Artery Blood Flow velocity (ml min-1) will be measured using Doppler ultrasonography (uSmart 3300, Terason) interfaced with the Quipu analysis software. Brachial Artery blood flow is calculated using brachial artery blood velocity and diameter during1 minute of recording in a resting state
Measured: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Superficial Femoral Artery Shear Rate
Superficial Femoral Artery Shear Rate shear rate (s-1) will be measured using Doppler ultrasonography (uSmart 3300, Terason) interfaced with the Quipu analysis software, during 1 minute in the resting state
Measured: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Brachial Artery Shear Rate
Brachial Artery Shear Rate shear rate (s-1) will be measured using Doppler ultrasonography (uSmart 3300, Terason) interfaced with the Quipu analysis software, during 1 minute in the resting state
Measured: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Dec 2025
- Study start2 Aug 2022
- Primary completion24 Aug 2023
- Study completion24 Aug 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies 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
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Birmingham
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07265869
- Sponsor's protocol ID
- ERN_19-0851B
- Status last verified
- Oct 2025
- First submitted
- 19 Nov 2025
- Last updated
- 5 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 5 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Placebo-controlled, Randomized, Double-masked, Cross-over Acute Intervention Study Investigating the Effects of Cocoa Flavanols on Peripheral Endothelial Function in the Context of Prolonged Sitting in Healthy Older Adults
- ClinicalTrials.gov ID
- NCT07265869
- Acronym / sponsor ID
- ERN_19-0851B
- Keywords
- vascular function, endothelial function, flow-mediated dilatation, flavanols, cocoa, flavonoids, polyphenols, sitting
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University of BirminghamUniversity, hospital or other
- Study start
- 2 Aug 2022 (actual)
- Primary completion
- 24 Aug 2023 (actual)
- Study completion
- 24 Aug 2023 (actual)
- First posted
- 5 Dec 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.
Sitting time is high in older adults and has been shown to temporarily impair endothelial function and blood pressure. Flavanols, plant-derived compounds, acutely enhance endothelial function and reduce Blood pressure in older adults. The aim of this study is to investigate whether acute ingestion of cocoa flavanols can improve peripheral endothelial function and blood pressure during prolonged sitting in healthy older adults.
In a randomised, double-blinded, cross-over, placebo-controlled human study, 20 healthy older adults will consume either a high-flavanol (695 mg) or low-flavanol (5.6 mg) cocoa beverage immediately before a 2-hour sitting bout. Flow-mediated dilation (FMD) of the superficial femoral (SFA; primary outcome) and brachial (BA) arteries, and blood pressure, were assessed before and after sitting. Microvasculature haemodynamics were assessed in the gastrocnemius before, during, and after sitting. It is hypothesized that the high flavanol cocoa will prevent declines in brachial and superficial femoral Flow-mediated dilatation post sitting.
Detailed description
Older individuals are estimated to spend more than 10 hours in their waking day in sedentary activities , which can include sitting bouts lasting up to 5.4 hours/day . Greater sedentary time was found to be associated with a significantly increased risk of cardiovascular diseases and all-cause mortality. Several experimental studies have shown that even just one isolated episode of prolonged sitting (from 1 to 6 hours) has detrimental effects on human endothelial function, as measured by flow-mediated dilation (FMD).
Flavonoid-rich foods are typically consumed in high amounts in cardioprotective diets, with evidence from both observational and Randomised Controlled Trials showing flavonoids to improve biomarkers of cardiovascular health. Flavanols, a sub-group of flavonoids present in unprocessed cocoa, have been extensively shown to act quickly within the vasculature, improving both brachial Flow-mediated dilatation and lower-limb common femoral artery (CFA) Flow-mediated dilatation within 2 hours of intake in older adults.
The aim of the current study is to examine whether acute consumption of cocoa flavanols prior to a 2-hour bout of uninterrupted sitting can be beneficial in improving endothelial function (as measured by Flow mediated dilatation) in the upper-limb Brachial Artery (BA) and lower-limb Superficial Femoral Artery (SFA) in older adults, as well as downstream, muscle microvascular function. We will further investigate whether cocoa flavanols can prevent sitting-induced increases in blood pressure in older adults. We hypothesise that cocoa flavanols would be effective at rescuing upper- and lower-limb Flow-mediated dilatation and improve blood pressure during uninterrupted sitting in older age
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High-flavanol cocoa powder | Experimental | Dietary Supplement: High-flavanol cocoa powder12 g of fat-reduced natural cocoa powder containing 695 mg of total flavanols, including 150 mg (-)-epicatechin |
| Low-flavanol cocoa powder | Placebo comparator | Dietary Supplement: Low-flavanol cocoa powder12 g of fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols |
Who may qualify
- Ages
- 65 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (2 listed)
- Males and females
- aged 65 or more
Key exclusion criteria (7 listed)
- history or symptoms of cardiovascular, renal, pulmonary, metabolic, or neurologic disease, hypertension (blood pressure higher than 140/90 mm Hg, based on recent guidelines), diabetes mellitus, anaemia, asthma, immune conditions, or high cholesterol.
- smoker
- individuals who were on weight-reducing diets
- individuals taking anticoagulants,
- had recently undergone prolonged bed-rest periods
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 |
|---|---|---|
| High-flavanol cocoa powder12 g of a fat-reduced natural cocoa powder containing 150 mg of (-)-epicatechin, and 695 mg of total flavanols | Dietary supplement | High-flavanol cocoa powder |
| Low-flavanol cocoa powder12 g of a fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols | Dietary supplement | Low-flavanol cocoa powder |
Primary outcome
Flow-mediated dilatation of the superficial femoral artery
Time frame: Change from pre-intervention baseline to 2 hours post intervention /2 hours post sitting
Flow-mediated dilatation (FMD) of the superficial femoral artery. Expressed as percent FMD: change in brachial diameter from baseline to peak dilation following 5 minutes of arterial occlusion. Brachial artery diameter and blood flow will be measured using Doppler ultrasonography (uSmart 3300, Terason).
12 secondary outcomes
Flow-mediated dilatation of the brachial artery
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/ 2hours post sitting
Tissue oxygenation index (TOI) of Gastrocnemius skeletal muscle
Time frame: Change from pre-intervention baseline to 2 hours post-intervention / 2 hours of sitting
Normalized haemoglobin index (nTHI) of the gastrocnemius skeletal muscle
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Tissue oxygenation index (TOI) of Gastrocnemius skeletal muscle during 2 hours of sitting
Time frame: Post-intervention time points considered during sitting were 0 , 10 , 60 and 120 minutes.
Normalized haemoglobin index (nTHI) of Gastrocnemius skeletal muscle during 2 hours of sitting
Time frame: Post-intervention time points considered during sitting were 0 min , 10 min, 60 min and 120 min.
Brachial Systolic Blood Pressure (SBP)
Time frame: Change from pre-intervention baseline to 2 hours post-intervention / 2 hours of sitting
Brachial Diastolic Blood Pressure (DBP)
Time frame: Change from pre-intervention baseline to 2 hours post-intervention / 2 hours of sitting
Heart Rate
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Resting Superficial Femoral Artery Blood Flow
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Resting Brachial Artery Blood Flow
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Superficial Femoral Artery Shear Rate
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Brachial Artery Shear Rate
Time frame: Change from pre-intervention baseline to 2 hours post-intervention/2 hours sitting
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Dec 2025.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High-flavanol cocoa powder and Low-flavanol cocoa powder in people with Healthy and Ageing, run by University of Birmingham at 1 site in United Kingdom.
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 2 inclusion and 7 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: finished, as of the sponsor's last update on 5 Dec 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 United Kingdom. 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. Some participants in this study may receive a placebo. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Flow-mediated dilatation of the superficial femoral artery (time frame: Change from pre-intervention baseline to 2 hours post intervention /2 hours post sitting). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 5 Dec 2025.