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CardiovascularNCT07396857

The Role of EDHFs on Blood Pressure Following a Bout of Prolonged Sitting

A study testing Fluconazole 150 mg in people with Cardiovascular, run by Université de Sherbrooke at 1 site in Canada.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

Canadians spend most of their day in sedentary postures (i.e., sitting, lying, reclining). While the beneficial impacts of physical activity on the heart are well-established, less is known about the consequences during time spent in sedentary postures. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
Conditions the study is for
Cardiovascular
What is being tested?
Fluconazole 150 mg
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
40 participants
Where
1 siteCanada
Study dates
1 Nov 2025to 15 Dec 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 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Are between the ages of 18-65.
  • Have a body mass index of <40kg/m2 (non-obese).
  • Have not smoked nicotine or marijuana-containing products most days of the week within the past 6 months.
  • Have not been diagnosed with a cardiovascular, cerebrovascular, respiratory, or metabolic disease.
  • Are normotensive.
  • Are not currently taking any medications for cardiovascular, metabolic, pulmonary, or neurological disorders, or taking sildenafil regularly.
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  • Are not allergic to the adhesive used to secure the activPAL activity monitors.
  • Are not pregnant or breastfeeding.
  • Are not regularly taking any of the following: another anti-fungal, heartburn medications containing cisapride (e.g., Propulsid), depression medications containing amitriptyline (e.g., Elavil) or nortriptyline (e.g., Pamelor), erythromycin (antibiotic), lipid lower medications (i.e., statins), non-steroidal anti-inflammatory drugs (e.g., ibuprofen), or vitamin A supplements.

Who cannot join

  • o Younger than 18 years old. Individuals younger than 18 demonstrate more variable peak FMD responses and require multiple assessments to determine peak response.
  • Over the age of 65. There are age-related impacts on arterial function and the responses to sitting.
  • Body mass index of >40 kg/m2 (i.e., obese II category)(6-8).
  • Smoked nicotine or marijuana-containing products most days of the week within the past 6 months. Cardiovascular health for participants who smoke is poor compared to those who do not smoke, which will negatively impact our arterial function outcomes.
  • Have been diagnosed with a cardiovascular, cerebrovascular, respiratory, or metabolic disease. Such conditions impact our assessments of arterial health. The results of unhealthy participants are not of interest in this study.
  • Hypertension (seated resting systolic pressure >139 mmHg and/or diastolic pressure >89 mmHg). Hypertensive individuals have impairments in artery health, which will affect their baseline artery health measures.
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  • Hypotensive (seated resting systolic pressure <90 mmHg and/or diastolic pressure <60 mmHg). Hypotensive people are more likely to experience further reductions in blood pressure during the sitting protocol, which will increase the risk of fainting and/or dizziness.
  • Have a history of fainting and/or dizziness during sitting or standing.
  • Prescribed medications for cardiovascular, metabolic, pulmonary, or neurological disorders. This includes people using hormone replacement therapy. These medications will interfere with our assessments and interpretation of arterial health.
  • Have a known allergy to the clear medical adhesive used to secure the activPAL activity monitors.
  • Females who are pregnant or breastfeeding. Pregnant and breastfeeding females are ineligible to participate. This is due to the known increases in arterial vasodilation associated with pregnancy related sex hormones.
  • Currently or recently (within the past 6 months) regularly taking sildenafil or other medications that increase the relaxing effects of nitric oxide in arteries. Such medication will influence artery blood flow and flow-mediated dilation responses.
  • Are regularly taking any of the following: another anti-fungal, heartburn medications containing cisapride (e.g., Propulsid), depression medications containing amitriptyline (e.g., Elavil) or nortriptyline (e.g., Pamelor), erythromycin (antibiotic), lipid lower medications (i.e., statins), non-steroidal anti-inflammatory drugs (e.g., ibuprofen), or vitamin A supplements. These are to minimize the chance of a participant experiencing an adverse reaction to the fluconazole tablet.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Molly K Courish, MSc, PhD(s) contact

902-818-0783

molly.courish@dal.ca

Canada1 site, 1 recruiting

  • Dalhousie University

    Halifax, Nova Scotia, B3H4R2

    Molly K Courish, MSc, PhD(s), 902-818-0783, molly.courish@dal.ca

    Recruiting

Other trials in Canada

About this study

Official title: The Role of Endothelial-Derived Hyperpolarization Factors on 24-hr Blood Pressure Regulation Following a Bout of Prolonged Sitting

Canadians spend most of their day in sedentary postures (i.e., sitting, lying, reclining). While the beneficial impacts of physical activity on the heart are well-established, less is known about the consequences during time spent in sedentary postures. Currently, we know that spending time in a bout of uninterrupted sitting disrupts blood pressure regulation. However, it is unknown if there are any 'carry over' effects following uninterrupted sitting bouts (i.e., over the next 24-hours). The release of chemicals from arteries controls how stiff or relaxed they are and is important for controlling blood pressure. This is especially true for arteries directly impacted by sitting (e.g., the popliteal artery behind the knee) and that send blood to the brain (e.g., the carotid artery). We have also established that endothelial-derived hyperpolarizing factors (EDHF, chemicals that relax the artery) are important for the relaxation of the artery the popliteal artery. However, we do not know if the effects of EDHFs on this artery are decreased during or after a bout of uninterrupted sitting. A bout of prolonged sitting also causes blood pressure and fluctuations in blood pressure to increase. Importantly, we reported that fluctuations in blood pressure caused by sitting are higher in young males versus females, but average blood pressure was higher among females. These findings suggest that sitting exerts sex differences in the control of blood pressure. Importantly, these effects were only demonstrated during the 2-hour bout of sitting. As such, it is unknown whether blood pressure is negatively impacted after prolonged sitting. The proposed study will determine the impact of EDHFs on blood pressure regulation following a 2-hour bout of prolonged sitting among a group of healthy males and females. Continuous heart rate (via electrocardiogram) and blood pressure (via finger cuff), as well as blood flow from the common carotid artery (in the neck), middle cerebral artery (in the brain) and popliteal artery (behind the knee) will be measured before and after sitting (via ultrasound). The ability of the popliteal artery to relax will be assessed using ultrasound following the release of a pressure cuff. Finally, 24-hour blood pressure and heart rate will be recorded after sitting using a monitor worn for 24-hours. The role of EDHFs will be investigated by comparing 1) baseline blood flow and blood pressure responses (no sitting), 2) blood pressure responses following a 2-hour bout of sitting, and 3) the blood pressure responses following a 2-hour bout of sitting while suppressing the release of EDHFs (via fluconazole ingestion).

Conditions
Cardiovascular
Being tested
Placebo, Fluconazole 150 mg
Keywords
Arterial function, Sedentary time, Sex differences, Vasoactive substances
Medical subject headings
Sedentary Behavior

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PlaceboDrug

    Participants will take a placebo sugar pill before and after a bout of prolonged sitting as a control session.

  • Fluconazole 150 mgDrug

    Participants will take 150mg of fluconazole, an EDHF inhibitor before and after a bout of prolonged sitting.

Study groups in NCT07396857
Study groupRoleWhat they receive
MalesExperimentalNot described
Receives: Drug: Placebo; Drug: Fluconazole 150 mg
FemalesExperimentalNot described
Receives: Drug: Placebo; Drug: Fluconazole 150 mg

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Popliteal Low-Flow Mediated Constriction

    During a period of distal cuff-induced ischemia, the endothelial-dependent vasoconstrictor response will be assessed via Duplex ultrasonography. The popliteal artery will be imaged slightly above the popliteal fossa. The L-FMC response will be quantified as the percent reduction in arterial diameter from baseline to the nadir diameter from the last 30-s of a 5-min distal cuff occlusion period.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting

  2. Acute Blood Pressure

    Beat-by-beat systolic (SBP) and diastolic (DBP) blood pressure will be measured using finger photoplethysmography for 20 minutes before the bout of prolonged sitting, 20 minutes after 1-hour of sitting, and 20 minutes after 2-hours of sitting. Mean arterial pressure will be quantified as 1/3 SBP + 2/3 DBP.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

  3. Ambulatory Blood Pressure

    Using an ABPMpro Ambulatory Blood Pressure Monitors, habitual blood pressure will be measured every 20-minutes during waking hours, and every 30-minutes during sleeping hours.

    Measured: This will be worn for a 24-hour period before the first prolonged sitting session, and for 24-hours after each bout of prolonged sitting.

Secondary outcomes (12)

  1. Carotid Artery Blood Flow Velocity

    Blood flow velocity will be measured immediately prior to the bifurcation in the common carotid artery using Duplex ultrasonography for 5 minutes.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

  2. Middle Cerebral Artery Velocity

    Blood flow velocity will be measured via transcranial Doppler over the trans-temporal window for 5 minutes.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

  3. Popliteal Flow Mediated Dilation (FMD)

    Following a period of distal cuff induced ischemia, the endothelial-dependent vasodilator response will be assessed via Duplex ultrasonography. The popliteal artery will be imaged slightly above the popliteal fossa. The FMD response will be quantified as the percent increase in arterial diameter from baseline to the peak diameter following the release of the distal cuff.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

  4. Physical Activity Behaviour Questionnaire

    A subjective questionnaire that provides information regarding habitual physical activity and sedentary behaviours.

    Measured: At time of study enrolment

  5. Heart Rate Variability (HRV)

    Heart rate will be determined using cardiac intervals from a lead II electrocardiography during prolonged sitting, and from the built-in electrocardiogram in the ambulatory blood pressure monitor. HRV will be derived from these waveforms using an offline HRV analysis module. Time-domain (I.e., RMSSD), frequency-domain, low frequency (LF) power, high frequency (HF) power, and the LF/HF ratio will be quantified for each participant.

    Measured: Acute: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting. Ambulatory: 24-hours at baseline, 24-hours after each bout of prolonged sitting.

  6. Carotid Intima Media Thickness (cIMT)

    cIMT will be determined from a 5-minute recording of the carotid artery, imaged prior to the bifurcation using Duplex ultrasonography.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

  7. Carotid Artery Distensibility

    Distensibility will be determined from 5-minutes of recorded carotid artery imaging via Duplex ultrasonography, and will be calculated as the difference between average arterial diameter during systole and diastole.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

  8. Blood Pressure Varibility (BPV)

    Beat-by-beat BPV during sitting will be quantified using the blood pressure measurements derived from finger photoplethysmography. This will be calculated as the average absolute difference between successive finger blood pressure measurements, for systolic blood pressure, diastolic blood pressure, and mean arterial pressure. Ambulatory BPV will be quantified from the 24-hour blood pressure monitors.

    Measured: Acute: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting. Ambulatory: 24-hours at baseline, 24-hours after each bout of prolonged sitting.

  9. Cardiovagal Baroreflex Sensitivity (cvBRS)

    cvBRS will be quantified from beat-by-beat systolic blood pressure (SBP) and R-R intervals in a cvBRS software. cvBRS outcomes will be quantified from a minimum of 3 sequences in which beat-by-beat SBP changes were ≥1 mmHg and changes in R-R interval were ≥ 1 ms. Overall cvBRS is represented by the average slope of SBP and R-R interval regressions for the pooled sequences, and reported separately for both up and down sequences. Baroreflex effectiveness index (BEI) will be measured as the ratio of the number of SBP ramp-induced changes in RR interval to the total number of SBP ramps observed. This will be reported separately for both up and down sequences. This will be measured over a 20-minute time period.

    Measured: Before prolonged sitting, after 1 hour of sitting, after 2-hours of sitting.

  10. Habitual Activity

    Habitual activity will be measured using activPAL inclinometer-accelerometers positioned on the torso, thigh, and calf. Monitors will be waterproofed and attached 24-hr/day for 8 days via clear medical adhesive. Physical activity will be determined via validated, custom software that was developed and openly published by our group.

    Measured: Before first bout of sitting, after each bout of sitting.

  11. Habitual Postures

    Habitual postures will be measured using activPAL inclinometer-accelerometers positioned on the torso, thigh, and calf. Monitors will be waterproofed and attached 24-hr/day for 8 days via clear medical adhesive. Time spent in postures (e.g., sitting versus lying time) will be determined via validated, custom software that was developed and openly published by our group.

    Measured: Before first bout of sitting, after each bout of sitting.

  12. Baseline Arterial Diameters

    Arterial diameter of the popliteal and carotid arteries will be determined via Duplex ultrasonography over a minimum of 2-minutes.

    Measured: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted9 Feb 2026
  2. Study start1 Nov 2025
  3. Primary completion15 Dec 2026 (estimated)
  4. Study completion15 Dec 2026 (estimated)

Resources

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
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
40 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07396857
Sponsor's protocol ID
2025-7915
Status last verified
Apr 2026
First submitted
2 Feb 2026
Last updated
13 Apr 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: IPD will not be shared to maintain privacy and confidentiality of the participants.

Publications

  • Turner JR, Viera AJ, Shimbo D. Ambulatory blood pressure monitoring in clinical practice: a review. Am J Med. 2015 Jan;128(1):14-20. doi: 10.1016/j.amjmed.2014.07.021. Epub 2014 Aug 12.

    PubMed 25107387

  • Pellerine LP, Miller K, Frayne RJ, O'Brien MW. Characterizing objective and self-report habitual physical activity and sedentary time in outpatients with an acquired brain injury. Sports Med Health Sci. 2024 Feb 10;6(4):338-343. doi: 10.1016/j.smhs.2024.02.001. eCollection 2024 Dec.

    PubMed 39309460

  • Bays HE, Toth PP, Kris-Etherton PM, Abate N, Aronne LJ, Brown WV, Gonzalez-Campoy JM, Jones SR, Kumar R, La Forge R, Samuel VT. Obesity, adiposity, and dyslipidemia: a consensus statement from the National Lipid Association. J Clin Lipidol. 2013 Jul-Aug;7(4):304-83. doi: 10.1016/j.jacl.2013.04.001. Epub 2013 May 31.

    PubMed 23890517

  • O'Brien MW, Johns JA, Al-Hinnawi A, Kimmerly DS. Popliteal flow-mediated dilatory responses to an acute bout of prolonged sitting between earlier and later phases of natural menstrual and oral contraceptive pill cycles. J Appl Physiol (1985). 2020 Oct 1;129(4):637-645. doi: 10.1152/japplphysiol.00424.2020. Epub 2020 Aug 13.

    PubMed 32790597

  • Liu H, O'Brien MW, Wu Y, Bustamante CM, Kimmerly DS. An acute bout of prolonged sitting blunts popliteal endothelium-independent dilation in young, healthy adults. J Appl Physiol (1985). 2023 Mar 1;134(3):521-528. doi: 10.1152/japplphysiol.00712.2022. Epub 2023 Jan 19.

    PubMed 36656984

  • Ishikura F, Beppu S, Hamada T, Khandheria BK, Seward JB, Nehra A. Effects of sildenafil citrate (Viagra) combined with nitrate on the heart. Circulation. 2000 Nov 14;102(20):2516-21. doi: 10.1161/01.cir.102.20.2516.

    PubMed 11076826

  • Lopes van Balen VA, van Gansewinkel TAG, de Haas S, van Kuijk SMJ, van Drongelen J, Ghossein-Doha C, Spaanderman MEA. Physiological adaptation of endothelial function to pregnancy: systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2017 Dec;50(6):697-708. doi: 10.1002/uog.17431.

    PubMed 28170124

  • Puranik R, Celermajer DS. Smoking and endothelial function. Prog Cardiovasc Dis. 2003 May-Jun;45(6):443-58. doi: 10.1053/pcad.2003.YPCAD13.

    PubMed 12800127

  • Jarvisalo MJ, Ronnemaa T, Volanen I, Kaitosaari T, Kallio K, Hartiala JJ, Irjala K, Viikari JS, Simell O, Raitakari OT. Brachial artery dilatation responses in healthy children and adolescents. Am J Physiol Heart Circ Physiol. 2002 Jan;282(1):H87-92. doi: 10.1152/ajpheart.2002.282.1.H87.

    PubMed 11748051

  • Tomiyama AJ, Hunger JM, Nguyen-Cuu J, Wells C. Misclassification of cardiometabolic health when using body mass index categories in NHANES 2005-2012. Int J Obes (Lond). 2016 May;40(5):883-6. doi: 10.1038/ijo.2016.17. Epub 2016 Feb 4.

    PubMed 26841729

  • Seals DR, Jablonski KL, Donato AJ. Aging and vascular endothelial function in humans. Clin Sci (Lond). 2011 May;120(9):357-75. doi: 10.1042/CS20100476.

    PubMed 21244363

  • Paterson C, Fryer S, Stone K, Zieff G, Turner L, Stoner L. The Effects of Acute Exposure to Prolonged Sitting, with and Without Interruption, on Peripheral Blood Pressure Among Adults: A Systematic Review and Meta-Analysis. Sports Med. 2022 Jun;52(6):1369-1383. doi: 10.1007/s40279-021-01614-7. Epub 2021 Dec 21.

    PubMed 34932203

  • Petterson JL, O'Brien MW, Johns JA, Chiasson J, Kimmerly DS. Influence of prostaglandins and endothelial-derived hyperpolarizing factors on brachial and popliteal endothelial-dependent function in young adults. J Appl Physiol (1985). 2021 Jan 1;130(1):17-25. doi: 10.1152/japplphysiol.00698.2020. Epub 2020 Oct 29.

    PubMed 33119467

  • Hall JE. Integration and regulation of cardiovascular function. Am J Physiol. 1999 Dec;277(6 Pt 2):S174-86. doi: 10.1152/advances.1999.277.6.S174.

    PubMed 10644245

  • Tremblay MS, Aubert S, Barnes JD, Saunders TJ, Carson V, Latimer-Cheung AE, Chastin SFM, Altenburg TM, Chinapaw MJM; SBRN Terminology Consensus Project Participants. Sedentary Behavior Research Network (SBRN) - Terminology Consensus Project process and outcome. Int J Behav Nutr Phys Act. 2017 Jun 10;14(1):75. doi: 10.1186/s12966-017-0525-8.

    PubMed 28599680

Questions about this trial

What is this clinical trial studying?

A study testing Fluconazole 150 mg in people with Cardiovascular, run by Université de Sherbrooke at 1 site in Canada.

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 9 inclusion and 13 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: looking for participants now, as of the sponsor's last update on 13 Apr 2026. 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 Canada. 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 Molly K Courish, MSc, PhD(s) (902-818-0783, molly.courish@dal.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Popliteal Low-Flow Mediated Constriction (time frame: Before prolonged sitting, after 1-hour of sitting, after 2-hours of sitting). The study lists 3 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 NCT07396857, which also lists 18 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 13 Apr 2026.

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