RecruitingNAINTERVENTIONAL

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

This research is investigating how long periods of sitting affect your blood pressure. We know that sitting still for a while can disrupt blood pressure regulation, but we don't fully understand if these effects continue hours or even a full day later. We're particularly interested in natural chemicals called EDHFs that help relax your blood vessels and control blood pressure, especially in areas like your legs and brain. The study will look at how sitting influences these chemicals and your blood pressure during and after a two-hour sitting period in healthy men and women. We'll also examine if there are differences based on whether you're male or female.

At a glance

Status

Recruiting

Phase

Sponsor

Université de Sherbrooke

Enrolment target

Start

01 Nov 2025

Estimated completion

15 Dec 2026

Cardiovascular

What is this study about?

Many of us spend a lot of time sitting down, whether at work, watching TV, or travelling. While we know that being active is good for our hearts, we don't fully understand how long periods of sitting affect our bodies, especially our blood pressure. This study aims to shed light on what happens to your blood pressure and blood vessels when you sit for a long time, and if these changes continue once you've stood up and moved around.

Our bodies naturally produce special chemicals called EDHFs (Endothelial-Derived Hyperpolarizing Factors) that help your arteries stay relaxed and healthy, which is important for keeping your blood pressure in check. We want to see if sitting for a couple of hours changes how these EDHFs work, especially in arteries in your legs and those that supply blood to your brain. We've noticed in previous studies that sitting might affect men and women differently when it comes to blood pressure, and we want to explore this further.

By understanding these effects, especially how long they last, scientists can learn more about the long-term health impacts of sedentary behaviour. This knowledge could eventually help us develop better advice for people to keep their hearts and blood vessels healthy, even if their lifestyle involves a lot of sitting.

Key takeaways

This study explores how long periods of sitting affect your blood pressure.
It investigates natural body chemicals that help your blood vessels relax.
Researchers will study if the effects of sitting last for hours or even a full day.
The study will look for differences in how sitting affects men and women.
Participation involves sitting, monitoring devices, and taking a study drug or placebo.
Your involvement helps improve our understanding of heart health and sedentary lifestyles.

Who may be eligible?

To join this study, you need to be a healthy adult between 18 and 65 years old. Your Body Mass Index (BMI) should be under 40, meaning you're not considered severely obese. It's important that you haven't recently smoked nicotine or cannabis products regularly, and you shouldn't have been diagnosed with any heart, blood vessel, lung, or metabolic conditions like diabetes. Your blood pressure should also be within a healthy range.

We also need to make sure you're not currently taking certain medications that could interfere with the study, such as treatments for heart conditions, some antibiotics, or certain anti-depressants. You also shouldn't be pregnant or breastfeeding, or have allergies to the sticky patches used for some of the monitoring equipment. If you're not sure about any of your medications, it's best to check with the study team.

We can't include individuals younger than 18 or older than 65 because artery function changes with age, and younger individuals' responses can vary a lot, making it harder to get clear results. Similarly, people with certain health conditions or those who smoke regularly have different artery health, which would affect what we're trying to measure in healthy participants.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 65 years old?
Do you have a healthy weight (BMI under 40)?
Have you been free from regular smoking (nicotine or cannabis) for the last 6 months?
Have you ever been diagnosed with heart, blood vessel, lung, or metabolic diseases?
Are you pregnant or breastfeeding?
Are you allergic to adhesive plasters or taking any regular medications for heart conditions, certain antibiotics, or anti-depressants?

Answer every question to see your result.

What does participation involve?

If you take part, you'll visit the study centre for a few assessments. Before you start, we'll measure your heart rate and blood pressure, and use an ultrasound (like a scan) to look at blood flow in your neck, brain, and behind your knee. We'll also check how well the artery behind your knee relaxes after a cuff is released.

During one part of the study, you'll sit for two hours. In another part, you'll take a study drug (either a placebo, which is a dummy pill, or 150mg of Fluconazole, which is a medication that affects the chemicals we're studying) before another two-hour sitting period. We'll measure your heart rate and blood pressure continuously during these times, and redo the ultrasound scans afterwards. For a full day after the sitting periods, you'll wear a small monitor to record your blood pressure and heart rate as you go about your usual activities. The total duration of your involvement will be explained to you by the study team, but it will involve a few visits and a 24-hour monitoring period.

Potential risks and benefits

Taking part in this study could help us learn more about how sitting affects our health, which could benefit many people in the future. You might not directly benefit, but you'll be contributing to important medical research. As with any study, there are some potential risks, such as minor discomfort from the blood pressure cuffs or wearing the monitoring devices, and very rare side effects from the study medication (Fluconazole). The study team will explain all known risks to you in detail. Remember, your participation is completely voluntary, and you are free to withdraw from the study at any time without giving a reason, and this will not affect your medical care.

Locations (1)

Dalhousie University
Verified postcode
Halifax, Canada· Recruiting

Common questions

What is the main goal of this study?

To understand how long periods of sitting affect your blood pressure and the natural chemicals that help your blood vessels relax, and if these effects last after you stop sitting.

Will I have to take any medication?

Yes, you will take either a dummy pill (placebo) or a study drug called Fluconazole as part of the research, to help us understand how certain chemicals work.

How long will I need to sit for?

You will have a planned period of two hours of uninterrupted sitting during the study visits.

What kind of tests will I have?

You'll have your heart rate and blood pressure monitored, and ultrasound scans to look at blood flow in your neck, brain, and leg before and after sitting. You'll also wear a 24-hour blood pressure monitor.

Will I get paid for taking part?

The study information will provide details on any reimbursement for your time and travel, if applicable.

How to find out more

Molly K Courish, MSc, PhD(s)

molly.courish@dal.ca 902-818-0783 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.