Cardiovascular Function in EMTsVF-EMTNCT06985394
Vascular Function and Oxidative Stress in Emergency Medical Responders
A study testing Antioxidant cocktail in people with Cardiovascular Function in EMTs, run by University of Delaware at 1 site in United States.
Trial summary
The goal of this clinical trial is to characterize blood vessel function and oxidative stress (a harmful condition that damages cells and tissues) in emergency medical technicians (EMTs). The main questions it aims to answer are: 1. Read more about this study
- Who is it for?
- Ages 20 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Cardiovascular Function in EMTs
- What is being tested?
- Antioxidant cocktail
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 45 participants
- Where
- 1 siteUnited States
- Study dates
- 14 May 2025to Oct 2025
- 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 20 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Body mass index between 18.5 and <35 kg/m²
- Seated resting systolic blood pressure < 140 mmHg, and seated resting diastolic blood pressure < 90 mmHg
- Participant must be an active first responder that works shift work schedules. e.g., emergency medical responders, basic life support emergency medical technicians (i.e., BLS EMT), advanced life support emergency medical technicians (A-EMT), and paramedics
- Participant must have been working shift work for at least 1 year
- Participant must work at least 4 night shifts per month
Who cannot join
- Participant is unwilling or unable to give consent
- Participant has been diagnosed with any chronic disease (a history of high blood pressure, heart disease, diabetes, cancer, kidney disease)
- Participant has been diagnosed with a sleep disorder (e.g., insomnia, restless leg syndrome, sleep apnea)
- Participant is currently taking melatonin or other sleep aids (e.g., Ambien, sedatives, etc.), or any supplements/medications known to alter sleep patterns. Participants using melatonin must undergo a minimum 72-hour washout period prior to study participation to ensure baseline sleep patterns are not affected[15, 16]
- Resting blood pressure >140/90 mmHg
- Body mass index <18.5 or >35 kg/m2
- Currently pregnant or breast feeding (women only)
- Currently use tobacco or nicotine products (≥1 cigarette, cigar, e-cigarette, vape, or any other nicotine-containing product in the last month), including smokeless tobacco (e.g., chewing tobacco, snuff, dip, snus), nicotine lozenges or gum, heated tobacco products, and any illicit drugs
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Delaware
Newark, Delaware, 19713
Alexs Matias, MS, 914-523-1953, amatias@udel.edu
About this study
The goal of this clinical trial is to characterize blood vessel function and oxidative stress (a harmful condition that damages cells and tissues) in emergency medical technicians (EMTs). The main questions it aims to answer are:
- Does an overnight shift work in emergency medical technicians reduce blood vessel function and increase oxidative stress?
- Can supplementing with antioxidants help reduce the negative effects of night shift work in emergency medical technicians?
Read more
Researchers will compare antioxidants to a placebo (a look-alike substance that contains no drug) to see if antioxidants work in reducing the negative effects of night shift work in emergency medical technicians.
Participants will:
- Report to the lab two separate times following an overnight shift to assess blood vessel functioning and oxidative stress 3. Take an antioxidant supplement or placebo during each night of shift work.
Read the detailed description
Heart disease, also referred to as cardiovascular disease, is the leading cause of death worldwide, responsible for about 30% of all deaths. While eating right, staying active, and avoiding cigarettes are key to preventing heart problems, the type of work a person does matters too. Some jobs can negatively affect heart health, especially those with night or irregular shifts. Emergency medical technicians (EMTs), the first responders who help keep our communities safe, often work these challenging schedules.
Shift work means working outside normal business hours-like evenings, nights, and weekends. These irregular schedules, especially overnight shifts, can disrupt the body's natural sleep cycle. This disruption can cause health problems because it goes against the body's internal clock, or circadian rhythm. This rhythm controls important functions like sleep, hormone levels, and heart health. When someone works at night, this clock is disrupted, which can lead to higher stress levels, worse blood vessel function, and even long-term damage to the heart. Research shows that people who work night shifts have a higher risk of heart disease compared to those who work during the day. The risk increases even more the longer someone works night shifts. In fact, studies show that each additional five years of night shift work raises the risk of heart problems by 7%. One night of shift work is all it takes to cause damage to blood vessels and spike stress levels in the body.
This study will examine how night shift work affects emergency medical technicians' heart and blood vessel health. The investigators will compare the function of their blood vessels and levels of oxidative stress (a harmful condition that damages cells and tissues) after working two overnight shifts. To understand how to best help reduce the negative effects of night shift work, this study will also test whether taking antioxidants-substances that protect the body from damage induced by oxidative stress-during one of the shifts can improve blood vessel health and reduce oxidative stress. Emergency medical technicians are a group that have not been researched much in this area and by doing so, this study hopes to learn more about how night shift work affects heart and blood vessel health. If antioxidants can help, this could lead to new ways of protecting shift workers from long-term heart problems-especially emergency medical technicians and first responders, who are vital to our community's safety.
- Conditions
- Cardiovascular Function in EMTs
- Being tested
- Antioxidant cocktail, Placebo
- Keywords
- EMT, First Responder, Oxidative Stress, Paramedic, Emergency Medical Technician
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Antioxidant cocktailDietary supplement
Participants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of the following concentrations of antioxidants:
600 mg of α-lipoic acid, 1,000 mg of vitamin C, and 600 IU of vitamin E.
PlaceboDietary supplement
Participants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of placebo pills made from microcrystalline cellulose, designed to match the antioxidants in taste, color, and appearance.
| Study group | Role | What they receive |
|---|---|---|
| Antioxidant Supplementation | Experimental | Participants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of the following concentrations of antioxidants:
600 mg of α-lipoic acid, 1,000 mg of vitamin C, and 600 IU of vitamin E. Receives: Dietary Supplement: Antioxidant cocktail |
| Placebo Supplementation | Placebo comparator | Participants will take two doses of placebo supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of placebo pills made from microcrystalline cellulose, designed to match the antioxidants in taste, color, and appearance Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Flow Mediated Dilation (FMD)
Flow-mediated dilation (FMD) is a frequently practiced non-invasive technique which images artery structure and blood flow before, during, and after a period of blood flow occlusion and subsequent increases in blood flow. This creates stress on the inner lining (i.e., endothelium) of the vasculature, inducing a cascade of events which results in relaxation of the smooth muscle surrounding the vessel. Reduced functioning of this mechanism is significantly associated with cardiovascular complications and disease. FMD will be used to assess the diameter and blood flow velocity of the artery located in the upper arm via ultrasonography.
Measured: Visit 2 (1 day)
Oxidative Stress
Electron Paramagnetic Resonance (EPR) Spectroscopy measurements will be conducted using a specialized spectrometer (Bruker EMX Nano) which is designed to detect unpaired electrons in biological samples, a key indicator of oxidative damage. For the EPR procedure, frozen samples of blood plasma will be carefully collected from the participant following standard clinical protocols during their vascular function visits. Briefly, the spin trapping technique will be used where a stabilizing molecule (e.g., spin probe such as cyclic hydroxylamine [CMH]) reacts with the free radical (e.g., superoxide) to form a more stable radical species for analysis (nitroxide). The stable sample will then be placed in the EPR resonator, and the spectrometer will be calibrated using known standards to ensure accurate detection of nitroxide.
Measured: Visit 3 (1 day)
Passive Leg Movement (PLM)
PLM is a newer, non-invasive method of assessing vascular function that is also mediated through the responsiveness of the endothelium. This assessment may provide additional insight on vascular function specific to the lower extremity. Briefly, participants will have one minute of blood flow velocity of the right femoral artery recorded (distal to inguinal crease, proximal to deep and superficial bifurcation) via Doppler ultrasound, while sitting with back upright, both legs supported, and knees fully extended (i.e., 180 degrees). Passive movement will then be initiated by a second team member who will continuously move the participant's right leg through 90 degrees of motion for two minutes. Participants will be urged to remain passive and to avoid any assistance with limb motion. Blood flow velocity of the right femoral artery will be continuously recorded during the entire 3 minute test to investigate changes in blood flow velocity during passive leg movement.
Measured: Visit 2 (1 day)
Flow Mediated Dilation (FMD)
Flow-mediated dilation (FMD) is a frequently practiced non-invasive technique which images artery structure and blood flow before, during, and after a period of blood flow occlusion and subsequent increases in blood flow. This creates stress on the inner lining (i.e., endothelium) of the vasculature, inducing a cascade of events which results in relaxation of the smooth muscle surrounding the vessel. Reduced functioning of this mechanism is significantly associated with cardiovascular complications and disease. FMD will be used to assess the diameter and blood flow velocity of the artery located in the upper arm via ultrasonography.
Measured: Visit 3 (1 day)
Passive Leg Movement (PLM)
PLM is a newer, non-invasive method of assessing vascular function that is also mediated through the responsiveness of the endothelium. This assessment may provide additional insight on vascular function specific to the lower extremity. Briefly, participants will have one minute of blood flow velocity of the right femoral artery recorded (distal to inguinal crease, proximal to deep and superficial bifurcation) via Doppler ultrasound, while sitting with back upright, both legs supported, and knees fully extended (i.e., 180 degrees). Passive movement will then be initiated by a second team member who will continuously move the participant's right leg through 90 degrees of motion for two minutes. Participants will be urged to remain passive and to avoid any assistance with limb motion. Blood flow velocity of the right femoral artery will be continuously recorded during the entire 3 minute test to investigate changes in blood flow velocity during passive leg movement.
Measured: Visit 3 (1 day)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 May 2025
- Study start14 May 2025
- Primary completionSep 2025 (estimated)
- Study completionOct 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cardiovascular Function in EMTsStudies 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
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 45 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Delaware
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06985394
- Sponsor's protocol ID
- 2291409-1
- Acronym
- VF-EMT
- Status last verified
- Feb 2025
- First submitted
- 25 Feb 2025
- Last updated
- 22 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: IPD will not be shared as this study is only being conducted at one location.
Study at a glance
From the registry record, last updated by the sponsor on 22 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Vascular Function and Oxidative Stress in Emergency Medical Responders
- ClinicalTrials.gov ID
- NCT06985394
- Acronym / sponsor ID
- VF-EMT / 2291409-1
- Conditions
- Cardiovascular Function in EMTs
- Keywords
- EMT, First Responder, Oxidative Stress, Paramedic, Emergency Medical Technician
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 45 participants (estimated)
- Lead sponsor
- University of DelawareUniversity, hospital or other
- Study start
- 14 May 2025 (actual)
- Primary completion
- Sep 2025 (estimated)
- Study completion
- Oct 2025 (estimated)
- First posted
- 22 May 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.
The goal of this clinical trial is to characterize blood vessel function and oxidative stress (a harmful condition that damages cells and tissues) in emergency medical technicians (EMTs). The main questions it aims to answer are:
- Does an overnight shift work in emergency medical technicians reduce blood vessel function and increase oxidative stress?
- Can supplementing with antioxidants help reduce the negative effects of night shift work in emergency medical technicians?
Researchers will compare antioxidants to a placebo (a look-alike substance that contains no drug) to see if antioxidants work in reducing the negative effects of night shift work in emergency medical technicians.
Participants will:
- Report to the lab two separate times following an overnight shift to assess blood vessel functioning and oxidative stress 3. Take an antioxidant supplement or placebo during each night of shift work.
Detailed description
Heart disease, also referred to as cardiovascular disease, is the leading cause of death worldwide, responsible for about 30% of all deaths. While eating right, staying active, and avoiding cigarettes are key to preventing heart problems, the type of work a person does matters too. Some jobs can negatively affect heart health, especially those with night or irregular shifts. Emergency medical technicians (EMTs), the first responders who help keep our communities safe, often work these challenging schedules.
Shift work means working outside normal business hours-like evenings, nights, and weekends. These irregular schedules, especially overnight shifts, can disrupt the body's natural sleep cycle. This disruption can cause health problems because it goes against the body's internal clock, or circadian rhythm. This rhythm controls important functions like sleep, hormone levels, and heart health. When someone works at night, this clock is disrupted, which can lead to higher stress levels, worse blood vessel function, and even long-term damage to the heart. Research shows that people who work night shifts have a higher risk of heart disease compared to those who work during the day. The risk increases even more the longer someone works night shifts. In fact, studies show that each additional five years of night shift work raises the risk of heart problems by 7%. One night of shift work is all it takes to cause damage to blood vessels and spike stress levels in the body.
This study will examine how night shift work affects emergency medical technicians' heart and blood vessel health. The investigators will compare the function of their blood vessels and levels of oxidative stress (a harmful condition that damages cells and tissues) after working two overnight shifts. To understand how to best help reduce the negative effects of night shift work, this study will also test whether taking antioxidants-substances that protect the body from damage induced by oxidative stress-during one of the shifts can improve blood vessel health and reduce oxidative stress. Emergency medical technicians are a group that have not been researched much in this area and by doing so, this study hopes to learn more about how night shift work affects heart and blood vessel health. If antioxidants can help, this could lead to new ways of protecting shift workers from long-term heart problems-especially emergency medical technicians and first responders, who are vital to our community's safety.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Antioxidant Supplementation | Experimental | Dietary Supplement: Antioxidant cocktailParticipants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of the following concentrations of antioxidants: 600 mg of α-lipoic acid, 1,000 mg of vitamin C, and 600 IU of vitamin E. |
| Placebo Supplementation | Placebo comparator | Dietary Supplement: PlaceboParticipants will take two doses of placebo supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of placebo pills made from microcrystalline cellulose, designed to match the antioxidants in taste, color, and appearance |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Body mass index between 18.5 and <35 kg/m²
- Seated resting systolic blood pressure < 140 mmHg, and seated resting diastolic blood pressure < 90 mmHg
- Participant must be an active first responder that works shift work schedules. e.g., emergency medical responders, basic life support emergency medical technicians (i.e., BLS EMT), advanced life support emergency medical technicians (A-EMT), and paramedics
- Participant must have been working shift work for at least 1 year
- Participant must work at least 4 night shifts per month
Key exclusion criteria (8 listed)
- Participant is unwilling or unable to give consent
- Participant has been diagnosed with any chronic disease (a history of high blood pressure, heart disease, diabetes, cancer, kidney disease)
- Participant has been diagnosed with a sleep disorder (e.g., insomnia, restless leg syndrome, sleep apnea)
- Participant is currently taking melatonin or other sleep aids (e.g., Ambien, sedatives, etc.), or any supplements/medications known to alter sleep patterns. Participants using melatonin must undergo a minimum 72-hour washout period prior to study participation to ensure baseline sleep patterns are not affected[15, 16]
- Resting blood pressure >140/90 mmHg
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 |
|---|---|---|
| Antioxidant cocktailParticipants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of the following concentrations of antioxidants: 600 mg of α-lipoic acid, 1,000 mg of vitamin C, and 600 IU of vitamin E. | Dietary supplement | Antioxidant Supplementation |
| PlaceboParticipants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of placebo pills made from microcrystalline cellulose, designed to match the antioxidants in taste, color, and appearance. | Dietary supplement | Placebo Supplementation |
Primary outcome
Flow Mediated Dilation (FMD)
Time frame: Visit 2 (1 day)
Flow-mediated dilation (FMD) is a frequently practiced non-invasive technique which images artery structure and blood flow before, during, and after a period of blood flow occlusion and subsequent increases in blood flow. This creates stress on the inner lining (i.e., endothelium) of the vasculature, inducing a cascade of events which results in relaxation of the smooth muscle surrounding the vessel. Reduced functioning of this mechanism is significantly associated with cardiovascular complications and disease. FMD will be used to assess the diameter and blood flow velocity of the artery located in the upper arm via ultrasonography.
Oxidative Stress
Time frame: Visit 3 (1 day)
Electron Paramagnetic Resonance (EPR) Spectroscopy measurements will be conducted using a specialized spectrometer (Bruker EMX Nano) which is designed to detect unpaired electrons in biological samples, a key indicator of oxidative damage. For the EPR procedure, frozen samples of blood plasma will be carefully collected from the participant following standard clinical protocols during their vascular function visits. Briefly, the spin trapping technique will be used where a stabilizing molecule (e.g., spin probe such as cyclic hydroxylamine [CMH]) reacts with the free radical (e.g., superoxide) to form a more stable radical species for analysis (nitroxide). The stable sample will then be placed in the EPR resonator, and the spectrometer will be calibrated using known standards to ensure accurate detection of nitroxide.
Passive Leg Movement (PLM)
Time frame: Visit 2 (1 day)
PLM is a newer, non-invasive method of assessing vascular function that is also mediated through the responsiveness of the endothelium. This assessment may provide additional insight on vascular function specific to the lower extremity. Briefly, participants will have one minute of blood flow velocity of the right femoral artery recorded (distal to inguinal crease, proximal to deep and superficial bifurcation) via Doppler ultrasound, while sitting with back upright, both legs supported, and knees fully extended (i.e., 180 degrees). Passive movement will then be initiated by a second team member who will continuously move the participant's right leg through 90 degrees of motion for two minutes. Participants will be urged to remain passive and to avoid any assistance with limb motion. Blood flow velocity of the right femoral artery will be continuously recorded during the entire 3 minute test to investigate changes in blood flow velocity during passive leg movement.
Flow Mediated Dilation (FMD)
Time frame: Visit 3 (1 day)
Flow-mediated dilation (FMD) is a frequently practiced non-invasive technique which images artery structure and blood flow before, during, and after a period of blood flow occlusion and subsequent increases in blood flow. This creates stress on the inner lining (i.e., endothelium) of the vasculature, inducing a cascade of events which results in relaxation of the smooth muscle surrounding the vessel. Reduced functioning of this mechanism is significantly associated with cardiovascular complications and disease. FMD will be used to assess the diameter and blood flow velocity of the artery located in the upper arm via ultrasonography.
Passive Leg Movement (PLM)
Time frame: Visit 3 (1 day)
PLM is a newer, non-invasive method of assessing vascular function that is also mediated through the responsiveness of the endothelium. This assessment may provide additional insight on vascular function specific to the lower extremity. Briefly, participants will have one minute of blood flow velocity of the right femoral artery recorded (distal to inguinal crease, proximal to deep and superficial bifurcation) via Doppler ultrasound, while sitting with back upright, both legs supported, and knees fully extended (i.e., 180 degrees). Passive movement will then be initiated by a second team member who will continuously move the participant's right leg through 90 degrees of motion for two minutes. Participants will be urged to remain passive and to avoid any assistance with limb motion. Blood flow velocity of the right femoral artery will be continuously recorded during the entire 3 minute test to investigate changes in blood flow velocity during passive leg movement.
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 22 May 2025.
- Individual participant dataSharing planned: No. IPD will not be shared as this study is only being conducted at one location.
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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Antioxidant cocktail in people with Cardiovascular Function in EMTs, run by University of Delaware at 1 site in United States.
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 5 inclusion and 8 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 22 May 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 States. 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?
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 Alexs Matias, MS (914-523-1953, amatias@udel.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Flow Mediated Dilation (FMD) (time frame: Visit 2 (1 day)). The study lists 5 primary outcomes in all. 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 22 May 2025.