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Trial registered on ANZCTR


Registration number
ACTRN12624000628549
Ethics application status
Approved
Date submitted
17/04/2024
Date registered
14/05/2024
Date last updated
14/05/2024
Date data sharing statement initially provided
14/05/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Sex differences in skeletal muscle microvascular blood flow in healthy young adults.
Scientific title
Sex differences in skeletal muscle microvascular blood flow and other cardiovascular responses to acute maximal exercise in healthy young adults.
Secondary ID [1] 311742 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cardiometabolic diseases 333224 0
Condition category
Condition code
Cardiovascular 329914 329914 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This is a cross-sectional study exploring potential sex differences in cardiovascular responses to a single bout of acute maximal exercise.

Intervention: single graded exercise test on a treadmill (modified Bruce protocol), to assess cardiorespiratory fitness (VO2peak), skeletal muscle microvascular blood flow, femoral artery blood flow, and cardiac responses to acute maximal exercise. Participants will begin walking at 2.7km/h with increasing speed and/or incline every three minutes until exhaustion (see below). VO2peak is calculated from the highest 10-second rolling average of breath-by-breath respiratory gas analysis (Quark RMR Gas Analyzer, Cosmed, Italy). Maximal effort (i.e., adherence to the intervention) will be determined by one or more of the following criteria: a plateau in VO2, heart rate 90% of age-predicted maximum, rating of perceived exertion (RPE) =17, and/or respiratory exchange ratio =1.1.. Electrocardiography will be recorded throughout, with heart rate, blood pressure, and RPE recorded at the end of each 3-minute stage. The testing session will be supervised by a minimum of two first aid trained research staff at Deakin University, Burwood Campus.

Modified Bruce Protocol Stages (3mins each)
Stage 1: 2.7km/h; 0% incline
Stage 2: 2.7km/h; 5% incline
Stage 3: 2.7km/h; 10% incline
Stage 4: 4km/h; 12% incline
Stage 5: 5.5km/h; 14% incline
Stage 6: 6.8km/h; 16% incline
Stage 7: 8km/h; 18% incline
Stage 8: 8.9km/h; 20% incline
Stage 9: 9.7km/h; 22% incline


Pre-intervention testing:
- Questionnaires to collect general health and medical information, menstrual cycle/oral contraceptive use, dietary habits (24 hour diet recall), and physical activity levels (questionnaire and accelerometer worn for 7 days). Participants will be required to wear the accelerometer for all waking hours, except during water-based activities (swimming/bathing). The questionnaires are one-time assessments, each requiring less than 10 minutes to complete. .
- Fasting clinical chemistries (glucose, insulin, total cholesterol, low density lipoprotein, high density lipoprotein, triglycerides, HbA1c, and female sex hormone concentrations).
- Body composition (height, weight, and lean/fat mass by DEXA).
- Central haemodynamics (systolic and diastolic pressure, pulse pressure, augmentation index, augmentation index at 75bpm, mean arterial pressure) and arterial stiffness assessed via pulse wave analysis and pulse wave velocity.
Intervention code [1] 328199 0
Treatment: Other
Comparator / control treatment
Comparator - males
Control group
Active

Outcomes
Primary outcome [1] 337679 0
Skeletal muscle microvascular blood flow responses to acute maximal exercise (composite of microvascular flow velocity and microvascular blood volume).
Timepoint [1] 337679 0
Pre-exercise, immediately after exercise, and 30 minutes post-exercise.
Secondary outcome [1] 432812 0
Femoral artery blood flow responses to acute maximal exercise (composite of femoral artery diameter and blood velocity).
Timepoint [1] 432812 0
Pre-exercise, 15 minutes post-exercise, and 30 minutes post-exercise.
Secondary outcome [2] 432813 0
Cardiac index
Timepoint [2] 432813 0
Pre-exercise, immediately after exercise, and 30 minutes post-exercise.
Secondary outcome [3] 433722 0
Blood glucose
Timepoint [3] 433722 0
Pre-exercise, 15 minutes post-exercise, 30 minutes post-exercise
Secondary outcome [4] 433723 0
Blood lactate
Timepoint [4] 433723 0
Pre-exercise, 15 minutes post-exercise, and 30 minutes post-exercise

Eligibility
Key inclusion criteria
Body mass index 18.5-30kg/m2
Minimum age
18 Years
Maximum age
45 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Diagnosis of insulin resistance/diabetes or cardiovascular disease; uncontrolled hypertension (brachial blood pressure >160/100mmHg); known liver/kidney disease; current or previous cancer; physical limitations to exercise; current or past smoker (12 months); currently engaging in >300mins/week of moderate to vigorous physical activity; pregnancy/lactation; irregular menstrual cycle; use of non-monophasic oral contraceptive pill; oral contraceptive pill use for non-contraceptive purposes; females who are peri- or post-menopausal; a previous reaction to Definity contrast agent.

Study design
Purpose of the study
Prevention
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/06/2024
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
34
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 316074 0
University
Name [1] 316074 0
Deakin University HDR funds
Country [1] 316074 0
Australia
Funding source category [2] 316075 0
University
Name [2] 316075 0
Deakin University Alfred Deakin Postdoctoral Research Fellowship
Country [2] 316075 0
Australia
Primary sponsor type
University
Name
Deakin University
Address
Country
Australia
Secondary sponsor category [1] 318241 0
None
Name [1] 318241 0
Address [1] 318241 0
Country [1] 318241 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 314893 0
Deakin University Human Research Ethics Committee (DUHREC)
Ethics committee address [1] 314893 0
Deakin University Melbourne Campus, 221 Burwood Highway, Burwood, Victoria, 3125
Ethics committee country [1] 314893 0
Australia
Date submitted for ethics approval [1] 314893 0
05/03/2024
Approval date [1] 314893 0
13/05/2024
Ethics approval number [1] 314893 0

Summary
Brief summary
This study will explore potential sex differences in skeletal muscle microvascular blood flow and other cardiovascular responses to acute maximal exercise in 34 healthy young adults (17 premenopausal females and 17 age-matched males). Microvascular blood flow will be assessed via contrast-enhanced ultrasound at rest, immediately after, and 30 minutes after completing a maximal graded exercise test. Additional assessments include heart and large artery function, body composition, physical activity levels, and blood sampling for biomarkers associated with cardiometabolic health. We hypothesise that healthy premenopausal females will have larger skeletal muscle microvascular blood flow responses to acute maximal exercise than age-matched males, reflecting their known greater vasodilatory responses in large arteries. Findings will inform sex-specific cardiovascular risk factors, and aid in the development of early detection strategies and more targeted prevention and management approaches.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 133074 0
Dr Kimberley Way
Address 133074 0
Deakin University, 221 Burwood Highway, Burwood, VIC, 3125
Country 133074 0
Australia
Phone 133074 0
+61 3 924 68894
Fax 133074 0
Email 133074 0
[email protected]
Contact person for public queries
Name 133075 0
Kimberley Way
Address 133075 0
Deakin University, 221 Burwood Highway, Burwood, VIC, 3125
Country 133075 0
Australia
Phone 133075 0
+61 3 924 68894
Fax 133075 0
Email 133075 0
[email protected]
Contact person for scientific queries
Name 133076 0
Kimberley Way
Address 133076 0
Deakin University, 221 Burwood Highway, Burwood, VIC, 3125
Country 133076 0
Australia
Phone 133076 0
+61 3 924 68894
Fax 133076 0
Email 133076 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Due to confidentiality data will not be shared.


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
21989Ethical approval    387504-(Uploaded-14-05-2024-14-49-51)-Study-related document.pdf



Results publications and other study-related documents

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No documents have been uploaded by study researchers.

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