Vascular Function in Healthy VolunteersNCT06908941
The Cardiovascular Benefits of Resistance Training and Dark Chocolate in Female Adults
A study testing dark chocolate, milk chocolate and high-intensity resistance exercise in people with Vascular Function in Healthy Volunteers, run by National Cheng Kung University at 1 site in Taiwan.
Trial summary
This study investigates the effects of 85% dark chocolate supplementation on vascular function and nitric oxide (NO) levels during high-intensity resistance exercise in healthy women across menstrual phases. Read more about this study
- Who is it for?
- Ages 20 to 30 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Vascular Function in Healthy Volunteers
- What is being tested?
- dark chocolate, milk chocolate and high-intensity resistance exercise
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 31 participants
- Where
- 1 siteTaiwan
- Study dates
- 1 Sep 2023to 31 Jul 2024
- 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 20 to 30 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- the healthy adult women,
- aged 20-30 years, from a local university campus,
- had a regular menstrual cycles in the past three months.
Who cannot join
- (1) irregular menstrual cycles (menstrual cycle length < 21 or > 35 days in the past three months),
- (2) pregnancy or lactation in the past year,
- (3) history of cardiovascular or uterine surgery in the past six months,
- (4) use of contraceptives or other female hormone medications,
- (5) smoking or alcohol consumption habits,
- (6) hypertension (blood pressure > 140/90 mmHg), chronic diseases, heart disease, or other cardiovascular conditions, (7) allergy to cocoa products, nuts, or fruits.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Cardiovascular Benefits of Dark Chocolate Supplementation Before High-intensity Resistance Exercise in the Early Follicular and Mid-luteal Phases of the Menstrual Cycle
This study investigates the effects of 85% dark chocolate supplementation on vascular function and nitric oxide (NO) levels during high-intensity resistance exercise in healthy women across menstrual phases. Using a randomized crossover design, 31 women consumed either dark chocolate or milk chocolate before exercising during the early follicular and mid-luteal phases. Vascular markers, including pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels, were measured at multiple time points.
Read the detailed description
Background:
Dark chocolate, rich in flavanols, may support vascular health by reducing arterial stiffness and blood pressure across menstrual phases. This study examined the effects of 85% dark chocolate on nitric oxide (NO) levels and vascular function during high-intensity resistance exercise in healthy women across the early follicular and mid-luteal phases.
Methods:
Thirty-one healthy women (aged 20-30 years) with regular menstrual cycles completed a randomized, crossover study (conducted at National Chung Cheng University, Sep-Dec 2023). Participants consumed either 85% dark chocolate or milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
- Conditions
- Vascular Function in Healthy Volunteers
- Being tested
- dark chocolate, milk chocolate, high-intensity resistance exercise
- Keywords
- dark chocolate, estrogen, cardiovascular function
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
dark chocolateDietary supplement
Participants consumed 85% dark chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
milk chocolateDietary supplement
Participants consumed milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
high-intensity resistance exerciseBehavioural
Participants performed high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles.
| Study group | Role | What they receive |
|---|---|---|
| Early Follicular | Experimental | Participants consumed either 85% dark chocolate or milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) phases of two menstrual cycles. Receives: Dietary Supplement: dark chocolate; Dietary Supplement: milk chocolate; Behavioral: high-intensity resistance exercise |
| Mid-Luteal | Active comparator | Participants consumed either 85% dark chocolate or milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the mid-luteal (days 18-24) phases of two menstrual cycles. Receives: Dietary Supplement: dark chocolate; Dietary Supplement: milk chocolate; Behavioral: high-intensity resistance exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Finger-Toe Pulse Wave Velocity (ftPWV)
Measurements at other time points are taken while participants are resting in the laboratory. Firstly, sensors for photoplethysmography (PPG) were placed on the right index finger and right big toe of the participants. These sensors were marked with an oily pen to ensure consistent placement throughout the experiment. The signals were then amplified using a Biopec MP150 (MP150, Biopac Systems Inc., Goleta, CA, USA), with each physiological signal collected for at least 150 seconds. The signals were analyzed using MATLAB to calculate the time difference between the two pulse waves. The length of the participant's body segments ( sternum to the right index finger, and sternum to the big toe of the right foot) was measured, and this value was divided by the average difference between 10 pulse waves (in the stable interval of 150 seconds) to calculate the ftPWV value (m/s).
Measured: Finger-toe pulse wave velocity (ftPWV) were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
Secondary outcomes (1)
Arterial Index
The arterial pressure volume index (API) and arterial velocity pulse index (AVI) are measured using the PASESA AVE-2000 (PASESA, Tokyo, Japan) with a wrapped around the right upper arm of seated participants. The API reflected the stiffness of peripheral arteries by assessing the pressure-volume relationship of the artery, while the AVI primarily reflected the stiffness of central arteries by analyzing the ratio of forward and reflected pressure waves. Each measurement was taken three times, and the average of the three readings was recorded.
Measured: Arterial index (API and AVI) were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Apr 2025
- Study start1 Sep 2023
- Primary completion31 Dec 2023
- Study completion31 Jul 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Vascular Function in Healthy VolunteersStudies 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
- EF-MC: early follicular-milk chocolate EF-DC: early follicular-dark chocolate ML-MC: Mid Luteal-milk chocolate ML-DC: Mid Luteal-dark chocolate
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 31 participants (actual)
Sponsor and investigators
- Lead sponsor
- National Cheng Kung University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Cheng-Shiun He, PhD, National Cheng Kung University
- Investigators
- Cheng-Shiun He Professor, Principal investigator, National Chung Cheng University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06908941
- Sponsor's protocol ID
- CCUREC111122101
- Status last verified
- Apr 2025
- First submitted
- 19 Mar 2025
- Last updated
- 4 Apr 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Gaynor-Metzinger SHA, Triplett NT, Meucci M, Fasczewski KS, Flinchum DH, Collier SR. Central arterial stiffness, wave reflection, and heart rate variability following 4-week high-intensity resistance training intervention in young active women. Eur J Appl Physiol. 2022 Oct;122(10):2283-2293. doi: 10.1007/s00421-022-05003-4. Epub 2022 Jul 19.
PubMed 35852625Wang CW, Fang SH, Yu TA, Chen LY, Wang CK, Wang SC, He CS. The Cardiovascular Benefits of Dark Chocolate Supplementation before High-Intensity Resistance Exercise in the Early Follicular and Mid-Luteal Phases of the Menstrual Cycle. Sports Med Open. 2025 Apr 18;11(1):39. doi: 10.1186/s40798-025-00850-9.
PubMed 40249472
Study at a glance
From the registry record, last updated by the sponsor on 4 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Cardiovascular Benefits of Dark Chocolate Supplementation Before High-intensity Resistance Exercise in the Early Follicular and Mid-luteal Phases of the Menstrual Cycle
- ClinicalTrials.gov ID
- NCT06908941
- Acronym / sponsor ID
- CCUREC111122101
- Conditions
- Vascular Function in Healthy Volunteers
- Keywords
- dark chocolate, estrogen, cardiovascular function
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 31 participants (actual)
- Lead sponsor
- National Cheng Kung UniversityUniversity, hospital or other
- Study start
- 1 Sep 2023 (actual)
- Primary completion
- 31 Dec 2023 (actual)
- Study completion
- 31 Jul 2024 (actual)
- First posted
- 3 Apr 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.
This study investigates the effects of 85% dark chocolate supplementation on vascular function and nitric oxide (NO) levels during high-intensity resistance exercise in healthy women across menstrual phases. Using a randomized crossover design, 31 women consumed either dark chocolate or milk chocolate before exercising during the early follicular and mid-luteal phases. Vascular markers, including pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels, were measured at multiple time points.
Detailed description
Background:
Dark chocolate, rich in flavanols, may support vascular health by reducing arterial stiffness and blood pressure across menstrual phases. This study examined the effects of 85% dark chocolate on nitric oxide (NO) levels and vascular function during high-intensity resistance exercise in healthy women across the early follicular and mid-luteal phases.
Methods:
Thirty-one healthy women (aged 20-30 years) with regular menstrual cycles completed a randomized, crossover study (conducted at National Chung Cheng University, Sep-Dec 2023). Participants consumed either 85% dark chocolate or milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- EF-MC: early follicular-milk chocolate EF-DC: early follicular-dark chocolate ML-MC: Mid Luteal-milk chocolate ML-DC: Mid Luteal-dark chocolate
| Arm | Type | Receives |
|---|---|---|
| Early Follicular | Experimental | Dietary Supplement: dark chocolate, Dietary Supplement: milk chocolate, Behavioral: high-intensity resistance exerciseParticipants consumed either 85% dark chocolate or milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) phases of two menstrual cycles. |
| Mid-Luteal | Active comparator | Dietary Supplement: dark chocolate, Dietary Supplement: milk chocolate, Behavioral: high-intensity resistance exerciseParticipants consumed either 85% dark chocolate or milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the mid-luteal (days 18-24) phases of two menstrual cycles. |
Who may qualify
- Ages
- 20 to 30 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- the healthy adult women,
- aged 20-30 years, from a local university campus,
- had a regular menstrual cycles in the past three months.
Key exclusion criteria (6 listed)
- (1) irregular menstrual cycles (menstrual cycle length < 21 or > 35 days in the past three months),
- (2) pregnancy or lactation in the past year,
- (3) history of cardiovascular or uterine surgery in the past six months,
- (4) use of contraceptives or other female hormone medications,
- (5) smoking or alcohol consumption habits,
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 |
|---|---|---|
| dark chocolateParticipants consumed 85% dark chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise. | Dietary supplement | Early Follicular, Mid-Luteal |
| milk chocolateParticipants consumed milk chocolate (1g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise. | Dietary supplement | Early Follicular, Mid-Luteal |
| high-intensity resistance exerciseParticipants performed high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. | Behavioural | Early Follicular, Mid-Luteal |
Primary outcome
Finger-Toe Pulse Wave Velocity (ftPWV)
Time frame: Finger-toe pulse wave velocity (ftPWV) were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
Measurements at other time points are taken while participants are resting in the laboratory. Firstly, sensors for photoplethysmography (PPG) were placed on the right index finger and right big toe of the participants. These sensors were marked with an oily pen to ensure consistent placement throughout the experiment. The signals were then amplified using a Biopec MP150 (MP150, Biopac Systems Inc., Goleta, CA, USA), with each physiological signal collected for at least 150 seconds. The signals were analyzed using MATLAB to calculate the time difference between the two pulse waves. The length of the participant's body segments ( sternum to the right index finger, and sternum to the big toe of the right foot) was measured, and this value was divided by the average difference between 10 pulse waves (in the stable interval of 150 seconds) to calculate the ftPWV value (m/s).
1 secondary outcome
Arterial Index
Time frame: Arterial index (API and AVI) were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.
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 4 Apr 2025.
- Results publication: PubMed 35852625Gaynor-Metzinger SHA, Triplett NT, Meucci M, Fasczewski KS, Flinchum DH, Collier SR. Central arterial stiffness, wave reflection, and heart rate variability following 4-week high-intensity resistance training intervention in young active women. Eur J Appl Physiol. 2022 Oct;122(10):2283-2293. doi: 10.1007/s00421-022-05003-4. Epub 2022 Jul 19.
- Derived from this study: PubMed 40249472Wang CW, Fang SH, Yu TA, Chen LY, Wang CK, Wang SC, He CS. The Cardiovascular Benefits of Dark Chocolate Supplementation before High-Intensity Resistance Exercise in the Early Follicular and Mid-Luteal Phases of the Menstrual Cycle. Sports Med Open. 2025 Apr 18;11(1):39. doi: 10.1186/s40798-025-00850-9.
- National Chung Cheng University Human Research Ethics CenterLink provided by the sponsor.
- 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.
Cheng-Shiun He Professor principal investigator
National Chung Cheng 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 dark chocolate, milk chocolate and high-intensity resistance exercise in people with Vascular Function in Healthy Volunteers, run by National Cheng Kung University at 1 site in Taiwan.
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 3 inclusion and 6 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 4 Apr 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 Taiwan. 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?
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?
Finger-Toe Pulse Wave Velocity (ftPWV) (time frame: Finger-toe pulse wave velocity (ftPWV) were measured at rest, 2 hours after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.). 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 NCT06908941, which also lists 2 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 4 Apr 2025.