Plain English Summary
Background and study aims
Prolonged periods of time spent inactive and sitting (sedentary) increases the risk of heart disease even if the person is active at other times. This means that even people who meet the government guidelines of 150 minutes of moderate physical activity per week may have a higher risk of heart disease if they spend long periods being sedentary (sitting). Heart disease is the leading cause of death in people with spinal cord injury which may be because they are highly sedentary. The aim of this study is to find out whether breaking up prolonged sedentary time lowers the heart disease risk of inactive people with spinal cord injury.
Who can participate?
Men aged 18-50 who have a spinal cord injury and are physically inactive
What does the study involve?
Participants are weighed and they undergo a dual energy x-ray absorptiometry (DXA) scan. This scan shows their bone density, fat mass and fat-free mass (bone and muscle) levels. Participants then take part in three different activities that each last 7 hours, with a break of at least 6 days between each activity. The three activities are uninterrupted sitting, where participants remain seated in their wheelchair at a desk for a 7-hour day, prolonged physical activity, where participants carry out a 40-minute bout of activity in the morning followed by uninterrupted sitting for the rest of a 7-hour day, and sitting plus activity breaks, where participants carry out 2-minute bouts of moderate-intensity exercise every 20 minutes over a 7-hour day. During the inactive periods the participants carry out desk-based activities on a computer, read, talk, or watch DVDs. Participants’ markers of heart disease risk are measured before and during the study, including levels of blood sugar and cholesterol after eating, insulin levels and blood pressure.
What are the possible benefits and risks of participating?
Breaking up prolonged sedentary time with regular short activity breaks may be an effective way to lower the risk of heart disease in people with spinal cord injury and a simple strategy that they are more likely to take part in. In the long term, the results will help to inform new physical activity and clinical care guidelines to reduce the risk of heart disease in people with a sedentary lifestyle including those with spinal cord injury. The benefit of having a DXA scan is that if participants are found to have low bone density they can consult their doctor about ways of reducing their risk of breaking a bone at a later date. Participants also receive information on their body fat levels from this scan. The risks of physical activity include: heart/muscle/bone damage, breathing problems, sickness, fainting, dehydration and overheating. Risks are minimised by asking participants to complete a health questionnaire before the activity and only allowing people who are healthy to complete exercise that is appropriate to them. These risks are very rare in healthy people. Participants may stop the test at any time. If any of the above symptoms occur, they are asked to stop the test and monitored for a reasonable time. There is a very small risk of contamination from blood sample collection and from using facemasks. However, these risks are minimised by using protective equipment, disinfecting all re-usable equipment and screening all participants with health questionnaires before they take part in the study. People with any blood borne disease or virus are not permitted to take part in the study. Only trained researchers take the blood samples and they adhere to guidelines to reduce the risk of cross-infection, which is very rare. As a part of this study participants are exposed to a very small amount of X-rays during their DXA scan(s). X-rays can cause harmful effects such as the development of cancer, but the amount used in this study is very, very tiny and there is a similar risk from less than 2 days of natural background radiation in the UK.
Where is the study run from?
University of Bedfordshire (UK)
When is the study starting and how long is it expected to run for?
November 2016 to February 2019
Who is funding the study?
Heart Research UK
Who is the main contact?
Dr Daniel Bailey
The Spinal Cord Injury Move More (SCIMM) study: benefits of breaking up prolonged sedentary time on cardiovascular disease risk markers in people with spinal cord injury
It is hypothesised that breaking up prolonged sedentary time will result in similar cardiovascular disease risk marker responses to a continuous energy-matched exercise session and that both of these conditions will result in more favourable risk marker responses than prolonged uninterrupted sedentary time in people with spinal cord injury.
Cambridge South NHS Research Ethics Committee, 13/05/2017, ref: 17/EE/0076
Randomised three-condition cross over study
Primary study design
Secondary study design
Randomised cross over trial
Patient information sheet
See additional files
Spinal cord injury
This is a randomised crossover design with three trial conditions that each last 7 hours with a minimum washout of at least 6 days between each condition. The study will test the heart disease risk marker responses to the three conditions below. A researcher who is not involved in participant recruitment and intervention will create a randomization list using the block randomization method (software: Research Randomizer, https://www.randomizer.org). This list will be provided to the study investigators. The investigator responsible for enrolment will remain blinded to the intervention allocations until 48 hours prior to the first main trial for each participant.
The trial conditions are:
1. Uninterrupted sitting (SIT): participants will remain seated uninterrupted in their wheelchair at a desk during the 7 h trial period
2. Continuous physical activity (CONT): participants will perform a continuous 40 min bout of moderate-intensity arm crank exercise 20 min after consuming a standardised breakfast meal, which will be followed by uninterrupted sitting at a desk for the rest of the day
3. Sitting + activity breaks (SIT-ACT): participants will perform 2 min of moderate-intensity arm crank exercise every 20 min during the 7 h day with the first bout taking place 20 min after breakfast. These 20 breaks will equate to 40 min and will match energy expenditure of the CONT trial condition
The moderate-intensity exercise in the CONT and SIT-ACT conditions will be performed at a power output corresponding to 40% VO2Reserve. During the inactive periods the volunteers will carry out desk-based activities on a computer, read, talk, or watch DVDs.
Before and during the trial, the researchers will measure each participant’s levels of blood sugar and cholesterol after eating, insulin levels and blood pressure. There is no follow-up.
Primary outcome measures
Postprandial plasma glucose concentration incremental area under the curve, measured spectrophotometrically from venous blood samples collected at baseline and then hourly during each of the three trial conditions
Secondary outcome measures
1. Incremental area under the curve for postprandial triglycerides, measured spectrophotometrically from venous blood samples collected at baseline and then hourly during each of the three trial conditions
2. Incremental area under the curve for HDL, measured spectrophotometrically from venous blood samples collected at baseline and then hourly during each of the three trial conditions
3. Incremental area under the curve for insulin, measured using an enzyme immunoassay from venous blood samples collected at baseline and then hourly during each of the three trial conditions
4. Total area under the curve for IL-6, measured using an enzyme immunoassay from venous blood samples collected at baseline and then hourly during each of the three trial conditions
5. Systolic and diastolic blood pressure, measured using an automated oscillatory blood pressure monitor at baseline and then hourly during each trial
Overall trial start date
Overall trial end date
Participant inclusion criteria
2. Aged 18-50 years
3. Physically inactive: engaging in less than <150 min per week of moderate-to-vigorous physical activity
4. Have a chronic spinal cord injury (≥1 year since injury)
5. Injured at Thoracic level 6 to Sacral Level 5 (mild to low level paraplegia). These individuals have intact sympathetic innervation to the heart and resting blood pressure is typically normal
Target number of participants
Participant exclusion criteria
1. Diagnosed diabetes, hypertension, hypotension, renal failure, liver disease, or history of severe cardiovascular complications
2. Body mass index >45 kg/m2 (severe obesity)
3. A history of autonomic dysreflexia
4. Taking glucose or lipid-lowering medication
6. Major illness or other health issues that may limit ability to perform the exercise protocols
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
University of Bedfordshire
Heart Research UK
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Planned publication in a high-impact peer-reviewed journal.
IPD sharing plan
The datasets generated during and/or analysed during the current study are/will be available upon request from Dr Daniel Bailey (firstname.lastname@example.org).
Intention to publish date
Participant level data
Available on request
Results - basic reporting
- ISRCTN51868437_PIS_01Feb17.docx Uploaded 21/02/2017