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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Understanding the negative effects of prolonged sitting: investigating the impact on musculoskeletal discomfort and cardiovascular parameters
Scientific title
Understanding the negative effects of prolonged sitting: investigating the impact on musculoskeletal discomfort and cardiovascular parameters
Secondary ID [1] 289032 0
Universal Trial Number (UTN)
Trial acronym
Sit Pilot
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 2 Diabetes Mellitus 298448 0
Condition category
Condition code
Diet and Nutrition 298548 298548 0 0
Metabolic and Endocrine 298549 298549 0 0

Study type
Description of intervention(s) / exposure
Participation will involve 2 visits over 1-2 weeks.
1) Consent and screening: including full disclosure of the project aims and requirements; collecting information on medical history; measurements of height, weight, hip and waist, and blood pressure.
2) Experimental Procedure: To minimise potential variability, participants will be asked to refrain from alcohol, caffeine and moderate-to-vigorous activity in the 48 hours prior to the experimental day. They will also be provided with a pre-dinner meal to be consumed between 7-9pm the night before, after which they will be instructed to fast until the beginning of the trial the next morning. Adherence to these requests will be determined via food and activity diaries. On the morning of the trial, following equipment set-up, the participant will be instructed to sit quietly for an initial 1 hour "steady state" period, during which time measurements will be recorded. The participant will then be provided with a breakfast meal, commencing the experimental condition thereafter. The breakfast meal will consist of 55% carbohydrate, 30% fat and 15% protein, and will provide 33% of daily energy needs, based on the Schofield equation. Participants will be asked to sit quietly in a comfortable chair for five hours. They can watch television, DVD’s or read whilst seated. They will be able to have a toilet break whenever they need, but will otherwise be asked to sit as still as possible to avoid interfering with measurement outcomes.
Continuous measures of blood pressure and heart rate (ECG) will be taken. EMG and posture will be recorded every 3 minutes; and discomfort scores every 10 minutes throughout the sitting period. Microneurography of the peroneal nerve will be measured from baseline to 2 hours post meal.
Intervention code [1] 294514 0
Comparator / control treatment
No control group - comparators involve comparing a time-course of events over the day to baseline measures.
Control group

Primary outcome [1] 298033 0
Musculoskeletal discomfort (assessed by visual analogue scale)
Timepoint [1] 298033 0
Every 10 minutes whilst participant is seated. Normally completed within 1 minute.
Primary outcome [2] 298059 0
Muscle activity measured using surface electromyography from muscles involving sitting (upper trapezius, lumbar erector spinae, quadriceps, hamstrings)
Timepoint [2] 298059 0
Every 3 minutes for a period of 15 seconds whilst the participant is seated
Primary outcome [3] 298060 0
Spinal posture measured via electromagnetic motion tracking
Timepoint [3] 298060 0
Recorded every 3 minutes for a period of 15 seconds whilst the participant is seated
Secondary outcome [1] 322975 0
postprandial glucose response, continuous assessment measured with a Continuous Glucose Monitor Sensor (CGMS)
Timepoint [1] 322975 0
Measured for 5 hours starting 10 minutes prior to breakfast meal consumption
Secondary outcome [2] 322976 0
Spontaneous Baroreflex (with ECG and continuous BP finapress)
Timepoint [2] 322976 0
Assessed at 30 minute intervals whilst seated for a period of 10 minutes
Secondary outcome [3] 322977 0
Muscle sympathetic nervous activity (MSNA) using microneurography. One microelectrode is inserted under the skin near the head of the fibula, and the other on top of the peroneal nerve.
Timepoint [3] 322977 0
From baseline to 2-hours post-meal

Key inclusion criteria
Participants will be overweight/obese, based on having a BMI between 25 kg/m2 and 40 kg/m2, previous diagnosis of type 2 diabetes greater than 3 months, and be english speaking.
Minimum age
55 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Conditions for exclusion are: diagnosis of type 2 diabetes for less than 3 months; unable to sit for prolonged periods due to musculoskeletal pain; pregnancy; employment in a non-sedentary occupation; currently watching less than 3 hours of television per day; regularly engaged in moderate-intensity exercise for greater than or equal to 150 min/week for greater than 3 months; use of glucose/lipid lowering/antidepressant medications; pre-menopausal or menopausal women; and major illness/physical problems.
These exclusion criteria are necessary to ensure our participants fall within the demographic in which the risk of cardiovascular and diabetic complications due to sedentary behaviour are elevated. This is the target group for future interventions in whom breaks from daily prolonged sitting are likely to be of most benefit.

Study design
Purpose of the study
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
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 293394 0
Government body
Name [1] 293394 0
National Health and Medical Research Council (NHMRC)
Address [1] 293394 0
Level 1
16 Marcus Clarke Street
Canberra ACT 2601
Country [1] 293394 0
Primary sponsor type
Professor David Dunstan
Physical Activity Laboratory
Baker IDI Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Secondary sponsor category [1] 292225 0
Name [1] 292225 0
Address [1] 292225 0
Country [1] 292225 0

Ethics approval
Ethics application status
Ethics committee name [1] 294851 0
Alfred Health Human Ethics Committee
Ethics committee address [1] 294851 0
Office of Ethics & Research Governance
Alfred Health
55 Commercial Road
Melbourne VIC 3004
PO Box 315 Prahran
VIC 3181 Australia
Ethics committee country [1] 294851 0
Date submitted for ethics approval [1] 294851 0
Approval date [1] 294851 0
Ethics approval number [1] 294851 0

Brief summary
Advances in technology, while providing a wide and varied range of benefits, have had the effect of engineering an environment where humans are continually encouraged to sit. This shift toward a more sedentary lifestyle has been linked to a myriad of poor health outcomes, including increased risk of cardiovascular disease, diabetes, and all-cause mortality. Compelling evidence indicates that the global burden of chronic disease and premature deaths attributable to physical inactivity is comparable to smoking. Over the past decade, our lab has revealed that sedentary behaviour (sitting) is associated with elevated markers of cardio-metabolic risk, and premature all-cause and cardiovascular disease mortality. Expanding on the evidence provided from observational studies, we have shown a beneficial effect of breaking up prolonged sitting time with light intensity physical activity on postprandial glucose and insulin metabolism, blood pressure and fibrinogen; and that some of these effects are being mediated by changes at the gene and protein expression level. Despite the progress that has been made, there still remains the question “how much sitting is too much”? This is likely to involve a complicated interplay between several different metabolic processes, and requires the ability to use continuous measures to determine the point at which negative effects occur. Teasing out the mechanisms and time-course of the negative impact of prolonged uninterrupted sitting is a vital next step which could help to inform future intervention strategies and activity guidelines.

In this pilot trial, we aim to assess the impact of 5 hours of prolonged, uninterrupted sitting on various physiological and metabolic parameters in overweight adults with type 2 diabetes (n=5). These parameters include:
(i) muscle activity and posture, leading to musculoskeletal discomfort
(ii) the baroreflex and orthostatic intolerance
(iii) sympathetic nervous system activity via microneurography
One of the main aims of this pilot trial is to test the feasibility of measuring all of these parameters at once, using our standard sitting intervention and musculoskeletal protocols. In particular, we aim to establish whether we can get useful EMG and posture measures with the other equipment and furniture being used; and also determine if we can get clear and meaningful microneurography measurements in the sitting position.
We hypothesise that reduced variation in muscle activity resulting from prolonged sitting and poor posture will lead to musculoskeletal discomfort. Moreover, prolonged sitting will lead to baroreflex dysfunction and orthostatic intolerance. Sympathetic nervous system activity will be tested only for feasibility in this pilot study.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 61806 0
Prof David Dunstan
Address 61806 0
Physical Activity Laboratory
Baker IDI Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country 61806 0
Phone 61806 0
+61 3 8532 1873
Fax 61806 0
+61 3 8532 1150
Email 61806 0
Contact person for public queries
Name 61807 0
Dr Megan Grace
Address 61807 0
Physical Activity Laboratory
Baker IDI Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country 61807 0
Phone 61807 0
+61 3 8532 1855
Fax 61807 0
+61 3 8532 1150
Email 61807 0
Contact person for scientific queries
Name 61808 0
Dr Megan Grace
Address 61808 0
Physical Activity Laboratory
Baker IDI Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country 61808 0
Phone 61808 0
Fax 61808 0
+61 3 8532 1150
Email 61808 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary