Overview
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.
Description
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.
Eligibility
Inclusion Criteria:
- Adult women diagnosed with RA
- From the Rheumatology Clinic at the Liverpool University Hospitals NHS Foundation Trust
- Aged 18-60 yr
- Non-smoker for at least 6months
- Able to provide written informed consent.
Exclusion Criteria:
- Cannot readily read and understand English.
- Currently smoking or within last 6 months.
- Alcohol consumption >14units per week.
- Symptoms of or established cardiovascular disease (except hypertension)
- Previous stroke or myocardial infarction.
- History of diabetes or respiratory disease or chronic kidney disease.
- Musculoskeletal impairment/disability precluding physical activity
- Unstable medication (change in medication within the 3 months)
- Aged <18 or > 60 yr
- Currently pregnant