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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Taking regular breaks from sitting to improve blood glucose control and blood vessel health in type 1 diabetes
Scientific title
The acute effect of breaking up sitting with brief light-intensity simple resistance activities on glycemic control, blood pressure and vascular function in individuals with type 1 diabetes
Secondary ID [1] 293628 0
Universal Trial Number (UTN)
Trial acronym
The TARGET study: Taking Regular breaks from sitting to improve Glycemic control, blood pressure and Endothelial function in type 1 diabetes,
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 1 diabetes 305904 0
Condition category
Condition code
Metabolic and Endocrine 305092 305092 0 0
Cardiovascular 305093 305093 0 0

Study type
Description of intervention(s) / exposure
In this cross-over trial, participants will complete two 8 hour laboratory-based conditions (A or B), each separated by a 3 day wash out. After a 10-hour overnight fast, participants will arrive at the laboratory at 7:30am to complete a trial condition involving: (A) UNINTERRUPTED SITTING (control condition): Participants will sit quietly in a lounge chair throughout the 8 hr period; (B) SITTING + LIGHT-INTENSITY SIMPLE RESISTANCE ACTIVITY BREAKS: Following baseline measurements and after sitting quietly for 1 hour (steady state), participants will complete a 3 min bout of simple resistance activities. The activities will be allocated into nine 20 second segments, alternating between body weight half-squats, calf raises and brief gluteal contractions in-between single leg knee raises. To ensure appropriate standardisation, participants will be supervised by trained research staff and guided through a video-led demonstration of the simple resistance activities. They will then return to the seated position. This procedure will be repeated on a further 11 occasions every 30 min for a total of 36 min of light-intensity activity. During each condition, participants will consume a standard breakfast meal after an initial 60 minute steady state period and a lunch meal at midday. Meals will be prepared according to an individual's energy requirements (33% of total daily energy requirements, Schofeld equation) and breakfast and lunch will be standardised across each laboratory-based condition.
Intervention code [1] 299889 0
Intervention code [2] 299890 0
Comparator / control treatment
In a controlled laboratory environment, participants will complete 8 hours of prolonged sitting without breaks (only toilet breaks permitted). Participants will sit in a comfortable chair and will consume a standard breakfast meal after an initial 60 minute steady state period. Participants will also be fed a lunch meal at around midday. Meals will be prepared according to an individual's energy requirements (33% of total daily energy requirements, Schofeld equation) and breakfast and lunch will be standardised across each laboratory-based condition.
Control group

Primary outcome [1] 304269 0
Postprandial glycemic response calculated as mean incremental area under the curve (AUC) from half-hourly venous blood sampling over the 8-hour experimental conditions
Timepoint [1] 304269 0
Blood samples for assessment of plasma glucose will be collected half-hourly until the end of the 8 hr period during each experimental conditions
Secondary outcome [1] 341437 0
Changes in resting blood pressure using automated oscillometric blood pressure monitor
Timepoint [1] 341437 0
In each experimental condition, blood pressure will be measured every hour in a resting state

Key inclusion criteria
Eligibility will be based on: age (25-65 years), HbA1c (less than or equal to 10%), clinical diagnosis of type 1 diabetes for more than or equal to 12 months, and treatment with insulin pump therapy for more than or equal to 6 months, with pump settings reviewed by a health professional in the previous 3 months.
Minimum age
25 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Exclusion will be based on: use of glucose-lowering agents other than insulin (e.g. metformin, GLP1 agonist); clinical history of delayed gastric emptying; having experienced a severe hypoglycaemic episode (requiring assistance) within the last 3 months; BMI <20 or >30 kg/m2; highly active (moderate intensity physical activity >300 min/wk); severe vascular complications or other conditions limiting the ability to comply with study protocols (e.g. renal impairment eGFR <60; major cardiovascular or cerebrovascular event in the previous 12 months; hospitalisation due to diabetic ketoacidosis in the previous month); fasting C-peptide greater than or equal to 50 pmol/L; current smoker; and pregnancy.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
After obtaining informed consent and background information, potential participants will be screened to confirm eligibility. Once a potential subject has been deemed eligible, the subject will be randomised to the order of experimental conditions. The method for allocation concealment is closed envelopes. The allocation information will be placed in numbered envelopes (1 allocation per envelope) by an independent researcher. After a subject has been enrolled in the study, the study co-ordinators will contact an independent staff member to ask for the sequence of experimental conditions. The independent staff member will keep a log of the date and time the envelope was opened, the envelope number, the initials and gender of the participant and the order of experimental conditions. The study co-ordinator will also keep a record of this information.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation allocation sequence will be generated using computer –generated random numbers in a balanced orthogonal design
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not applicable
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Power calculations have been made in relation to the primary outcome measures of postprandial glucose (venous collections). Based on previous studies involving overweight/obese adults and those with type 2 diabetes (references 1 and 2), we have estimated that a sample size of 30 will be needed to detect a between treatment difference of 24% in postprandial glucose (incremental AUC) with a minimum power of 80% and a probability of 0.05 (2-tailed test). As a safeguard and using our experience from previous behavioural interventions, we will over-sample to cover an estimated attrition rate of 30%. Thus, 40 participants will be recruited.

Generalized linear mixed models (GLMMs) with random intercepts will be used to evaluate the differential effects of the experimental conditions on the outcomes. Analysis of the primary outcome (glucose incremental AUC) and secondary outcome (blood pressure) will be performed blinded to the treatment allocation. All models will include fixed effects for condition, period and order and random intercepts for repeated measures. GLMMs are appropriate for correlated data (repeated measures) with various distributional assumptions and can easily accommodate missing data. A probability level of 0.05 will be adopted.


1. Dunstan D, et al. Breaking up prolonged sitting reduces postprandial glucose and insulin responses. Diabetes Care 2012; 35: 976-983
2. Dempsey P, et al. Benefits for type 2 diabetes of interrupting prolonged sitting with brief bouts of light walking or simple resistance activities. Diab Care. 2016;34(12):2376-82.

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)
Recruitment hospital [1] 9606 0
Baker Heart and Diabetes Institute - Melbourne
Recruitment postcode(s) [1] 18363 0
3004 - Melbourne

Funding & Sponsors
Funding source category [1] 298245 0
Name [1] 298245 0
Diabetes Australia
Address [1] 298245 0
Level 1, 101 Northbourne Ave
Turner ACT 2612 Australia
Country [1] 298245 0
Primary sponsor type
Professor David Dunstan
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Secondary sponsor category [1] 297362 0
Name [1] 297362 0
Address [1] 297362 0
Country [1] 297362 0

Ethics approval
Ethics application status
Ethics committee name [1] 299253 0
Alfred Health Human Ethics Committee
Ethics committee address [1] 299253 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] 299253 0
Date submitted for ethics approval [1] 299253 0
Approval date [1] 299253 0
Ethics approval number [1] 299253 0
Project number 11/18

Brief summary
A primary treatment goal of intensive insulin therapy for type 1 diabetes (T1D) is to minimise excessive glucose excursions (hyper- and hypoglycaemia), which exacerbate the risk of chronic vascular complications, disability and premature death. Even with benefits from new technologies such as insulin pumps, achieving optimal glycaemic control in T1D remains a challenge. Those on intensive insulin therapy have several fold higher risk for developing cardiovascular disease compared to those without diabetes. Effective lifestyle-based approaches to improve blood glucose control could further assist in preventing or delaying the onset of the serious vascular complications of T1D.

Exercise recommendations for those with T1D have largely been based on studies showing benefits for those with and without type 2 diabetes (T2D). This is because exercise training studies in those with T1D have largely failed to demonstrate improved glycaemic control (HbA1c). Fear of exercise-related hypoglycaemia has been identified as the strongest barrier to exercise in adults with T1D, and epidemiological evidence suggests that those with T1D are just as inactive as their counterparts in the general population. There is now the need to identify practical and feasible lifestyle strategies that can help to optimise glycaemia and reduce the risk of diabetic complications.

There are emerging alternatives to the conventional notion of health-enhancing bouts of exercise. Reducing and breaking up sitting time shows promise. Prolonged unbroken sitting time is detrimentally associated with cardiometabolic risk biomarkers, T2D, cardiovascular disease and all-cause mortality. Recent experimental studies, have also shown that prolonged sitting is associated with acute elevations in postprandial glucose and insulin responses, and these adverse effects are attenuated with frequent breaks in sitting. However, these studies have focussed on those who are healthy or overweight without diabetes, or on those with T2D. Although T1D and T2D are distinct conditions, chronic sustained hyperglycaemia is unequivocally associated with increased risk of vascular disease in both forms of diabetes. Consequently, there is a need to evaluate the effect of reducing prolonged sitting on glycaemia and vascular risk factors in T1D, and the associated potential to minimise risk of serious diabetes complications.

In a randomised cross-over trial for adults with T1D, we will compare the acute cardiometabolic effects of three controlled experimental conditions:
• prolonged uninterrupted sitting
• prolonged sitting interrupted with regular short bouts of simple resistance activities

Findings from this trial will help to identify new options for the lifestyle management of T1D, which can be examined in more depth in subsequent studies.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 79798 0
Prof David Dunstan
Address 79798 0
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country 79798 0
Phone 79798 0
+61 3 8532 1873
Fax 79798 0
+61 3 8532 1150
Email 79798 0
Contact person for public queries
Name 79799 0
Dr Robyn Larsen
Address 79799 0
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country 79799 0
Phone 79799 0
+61 3 8532 1859
Fax 79799 0
+61 3 8532 1150
Email 79799 0
Contact person for scientific queries
Name 79800 0
Dr Paddy Dempsey
Address 79800 0
Physical Activity Laboratory
Baker Heart and Diabetes Institute
Level 4, Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country 79800 0
Phone 79800 0
+61 3 8532 1853
Fax 79800 0
+61 3 8532 1150
Email 79800 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Access to individual de-identified data that underlie the results reported in this article is subject to approval from the primary investigator and the Alfred Hospital Human Ethics Committee.
What supporting documents are/will be available?
No other documents available
Summary results
Not applicable