None listed
Conditions
Brief summary
Living a sedentary lifestyle significantly increases the risk of developing cardiovascular disease and having a subsequent cardiovascular event, such as a stroke. People who have had a stroke spend 75% of their waking hours at home sitting down, which is much higher than healthy age-matched individuals without stroke. This sedentary behaviour is damaging for stroke survivors already comprised cardiovascular health, and is likely a significant contributing factor to the recurrent stroke which 30% of survivors have after their initial event. Stroke survivors are very inactive; with very few able to engage in the level of physical activity recommended to improve their cardiovascular health. In people without stroke, breaking up prolonged sitting using regular activity breaks (walking or simple strengthening exercises) significantly improves cardiovascular disease risk factors such as blood pressure and glucose metabolism. Results from our recently completed pilot study indicates that breaking up prolonged sitting time in stroke survivors achieves similar cardiovascular benefits. Breaking up stroke survivor sitting time with simple resistance activities significantly reduced systolic blood pressure (mean 3.6 mmHg reduction). Lowering of blood pressure reduces the risk of hypertension, the leading modifiable risk factor associated with recurrent stroke, and thus has the potential to reduce the risk of recurrent stroke. Therefore, breaking up sitting time is a promising and innovative physical activity alternative to employ with stroke survivors to improve their cardiovascular health and subsequently, reduce recurrent stroke risk. The next important step is to determine the minimum amount and duration of activity breaks (dose) required to improve these cardiovascular risk factors in this population. This study will be the first to determine the optimal dose of simple resistance activities needed to reduce blood pressure and improve glucose metabolism in stroke survivors. Stroke survivors (n = 10 per cohort) living at home who are able to stand and walk will complete a baseline uninterrupted sitting condition followed by 2 dose-escalation conditions. Breaks in sitting will be light-intensity exercise while standing which will increase in 10-min increments each condition. Blood samples will be taken at regular intervals throughout each condition and blood pressure and physical activity will be monitored during and up until 24-hours post-condition. Outcomes of blood pressure (primary), blood glucose, insulin levels (secondary) and safety and feasibility indicators will be collected.
Interventions
A laboratory based, dose escalation study design will be used. Community dwelling stroke survivors with a moderate walking disability will be recruited to each cohort (n = 10/cohort).
All participants will complete 2 dose-escalation conditions, involving 10 min increments of light-intensity exercise whilst standing (STAND-EX), following a baseline (control) condition. STAND-EX will be split into 2 x 5 min breaks and consist of calf raises, mini squats and marching on the spot. The maximum dose
A laboratory based, dose escalation study design will be used. Community dwelling stroke survivors with a moderate walking disability will be recruited to each cohort (n = 10/cohort). All participants will complete 2 dose-escalation conditions, involving 10 min increments of light-intensity exercise whilst standing (STAND-EX), following a baseline (control) condition. STAND-EX will be split into 2 x 5 min breaks and consist of calf raises, mini squats and marching on the spot. The maximum dose of standing activities will be reached once the dose-limiting threshold (DLT) has been achieved. DLT: Failure to achieve at least 80% of the target time in STAND-EX due to fatigue, pain or effort required. The maximum dose for a cohort will be considered reached if 70% or more (n 'greater than or equal to' 7/10) of the cohort have met the DLT. Dose escalation: Cohort A – Prolonged, uninterrupted sitting (8 hours) will be broken up by 10 min STAND-EX, followed by 20 min STAND-EX on a separate occasion. Cohort B – Dose escalation will commence at 20 min STAND-EX and increase by a further 10 min. Cohort C – Dose escalation will repeat that of Cohort B. STAND-EX will be evenly distributed across the testing day (according to dose escalation). The initial dose escalation will involve 2 active standing breaks, each completed after the standardised meals (5 min at 09:00 and 5 min at 13:00). The frequency of breaks will increase until DLT is met. Each testing day will be separated by a minimum 4 day washout period. A standardised breakfast will be provided at approximately 8.30am and lunch at approximately 12.30pm. Meals will contain approximately one third of the participant's energy requirements and the combined macronutrient profile of testing day meals will be in line with the Acceptable Macronutrient Distribution Ranges as recommended by the Nutrient Reference Values for Australians and New Zealanders. Experimental conditions: 1. Uninterrupted sitting – 8 hours of prolonged, uninterrupted sitting in a comfortable lounge chair (excluding toilet breaks). 2. Dose escalation 1 – Complete the prescribed dose of STAND-EX 3. Dose escalation 2 – Complete an additional 10 minutes of STAND-EX above Dose escalation 1. Participants will be provided with an activity monitor and an ambulatory blood pressure monitor. All testing days will be supervised and take place at the Hunter Medical research Institute (HMRI).
Sponsors
University of Newcastle
Study design
Allocation
Non-randomised trial
Intervention model
Other
Primary purpose
Treatment
Masking
Blinded (masking used) (Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Stroke survivors who are: • Between 3 months and 10 years post-stroke with moderate walking disability as defined as, (1) Score of 'greater than or equal to' 3 on the Functional Ambulation Classification (i.e. can independently ambulate on level surfaces), (2) Walking speed of 'greater than or equal to' 0.4 metres per second • Able to toilet independently, • Able to stand from sitting in a lounge chair independently or with minimal assistance of 'less than or equal to' 1 person, • Highly sedentary (i.e. sit more than 7 hours during waking hours), • Aged 'greater than or equal to' 18 years.
Exclusion criteria
• employment in a non-sedentary occupation (i.e. non-office based occupation), • self-reported < 7 hours/day sitting, • regularly engaged in physical activity (i.e. 'greater than or equal to' 150 min/week) as assessed by self-report, • BMI > 45 kg/m2, • current smoker, • pregnant, • clinically diagnosed with acute/chronic illness or other condition which has known physical activity contraindications or limits their ability to complete each experimental condition (i.e. chronic low back pain aggravated by prolonged sitting), • urinary frequency and or urgency or requiring assistance with toileting (other than to mobilise to the toilet), and • insulin dependent diabetes or who are taking diabetes medication other than metformin.
Outcome results
None listed