This study will verify the effects of breaking up sitting time with short bouts of light intensity walking on vascular function in women with rheumatoid arthritis.
Women diagnosed with rheumatoid arthritis will participate in this randomized crossover trial. In one of the experimental sessions, the participants will remain 4-h on uninterrupted sitting, and in another day they will perform 3-min light intensity walk every 30 min to break up the sitting position. Vascular function will be assessed before and after each intervention using the following devices/techniques: a) transcranial Doppler ultrasound to assess the middle cerebral artery blood flow velocity at baseline and in response to CO2 breathing (5% CO2 mixture for 3 min), and to repeated sit-to-stand transitions; b) a multi-frequency linear transducer (7-12 MHz) attached to a high-resolution ultrasound machine to assess femoral artery dilation after reactive hyperemia (i.e., flow-mediated dilation); c) a laser Doppler probe attached to the skin surface of the right shin in order to quantify the Laser Doppler flux at baseline and during reactive hyperemia. Additionally, healthy age- and body mass-matched women will be recruited and will only perform the pre-intervention tests.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
12
Multiple bouts of 3-min brisk walking, every 30 min, for 4 hours.
Research Institute for Sport and Exercise Sciences (RISES)
Liverpool, Merseyside, United Kingdom
RECRUITINGMiddle cerebral artery mean velocity (MCAV)
MCAV will be assessed using continuous bilateral transcranial Doppler ultrasound.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Middle cerebral artery mean velocity reactivity to carbon dioxide
Participants will breathe a 5% carbon dioxide mixture for 3 min during which time MCAV reactivity to CO2 will be assessed using continuous bilateral transcranial Doppler ultrasound.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Cerebral autoregulation
Participants will be asked to complete a series of repeated sit to stand moves (coached by a member of the research team) for a 5-minute period, during which time MCAV will be assessed using continuous bilateral transcranial Doppler ultrasound. Beat by beat blood pressure will also be assessed using finger photoplethysmography.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Brachial artery endothelial function
Brachial artery endothelial function will be assessed through flow-mediated dilation using vascular ultrasound.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Finger blood pressure
During all procedures, beat by beat finger blood pressure will be measured on the middle finger of the right hand using photoplethysmography.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Superficial femoral artery endothelial function
Superficial femoral artery endothelial function will be assessed through flow-mediated dilation using vascular ultrasound.
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Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Skin blood flow response to hyperemia
Skin blood flow response to hyperemia will be assessed using a laser doppler probe attached to the shin and forearm.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Stroop color-word test
The Stroop color-word test will be implemented to assess attention and inhibitory control.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
California Verbal Learning Test-2
Immediate recall of the California Verbal Learning Test-2 will be used to assess verbal learning and memory.
Time frame: Change from baseline (hour 0) to hour 4 (post-intervention/control)
Brachial artery blood flow
Vascular ultrasound will be used to assess brachial artery blood flow every hour during the intervention
Time frame: Change from baseline to 1-hour/2-hour/3-hour/4-hour
Femoral artery blood flow
Vascular ultrasound will be used to assess femoral artery blood flow every hour during the intervention
Time frame: Change from baseline to 1-hour/2-hour/3-hour/4-hour
Pain intensity
Pain intensity will be assessed using a 10cm visual analogue scale.
Time frame: Change from baseline to 1-hour/2-hour/3-hour/4-hour