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Trial registered on ANZCTR

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

Titles & IDs
Public title
Sedentary behaviour and memory functions
Scientific title
The acute effect of prolonged sitting with and without intermittent bouts of light physical activity on cognitive functions in overweight/obese adults.
Secondary ID [1] 281875 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cognitive decline 288259 0
Overweight/obesity 288297 0
Condition category
Condition code
Mental Health 288611 288611 0 0
Studies of normal psychology, cognitive function and behaviour
Diet and Nutrition 288640 288640 0 0

Study type
Description of intervention(s) / exposure
This randomised crossover trial involves two single-day treatment conditions separated by a one week wash/out period. Intervention: Sitting + light-intensity activity bouts: Following an initial steady-state period (150 mins – initial 2 hours + 30 mins) of being seated, participants will complete a 3 min bout of light-intensity walking on the treadmill (level, firm surface, slow pace – 3.2 km/hr). They will then return to the seated position. This procedure will be repeated on another 9 occasions every 30 minutes. Total duration and intensity of activity: 30 minutes at light-intensity.
Intervention code [1] 286437 0
Intervention code [2] 286462 0
Intervention code [3] 286463 0
Comparator / control treatment
One day of prolonged sitting without activity breaks: Participants will sit quietly in a comfortable chair for a 7 hour period
Control group

Primary outcome [1] 288763 0
Executive functions (selective attention, shifting and inhibition) assessed by Stroop test, Eriksen flanker task, Letter memory, and N-back.
Timepoint [1] 288763 0
Baseline, at 4 hours, and at 7 hours.
Primary outcome [2] 288764 0
Short-term memory (visuospatial working memory) assessed by Corsi blocks.
Timepoint [2] 288764 0
Baseline, at 4 hours and at 7 hours.
Primary outcome [3] 288765 0
Long-term memory assessed by an episodic association test.
Timepoint [3] 288765 0
Baseline, at 4 hours and after 7 hours.
Secondary outcome [1] 300926 0
Interstitial glucose level measured by a CGMS (continuous glucose monitoring system)
Timepoint [1] 300926 0
Countinuous measurements during 7 hours
Secondary outcome [2] 300927 0
Plasma level of brain-derived neurotrophic factor, BDNF.
Timepoint [2] 300927 0
Baseline, at 4 hours and at 7 hours.
Secondary outcome [3] 300928 0
Plasma level of interleukin-6, IL-6.
Timepoint [3] 300928 0
Baseline, at 4 hours, and at 7 hours.
Secondary outcome [4] 300929 0
Plasma levels of catecholamines (adrenaline and noradrenaline).
Timepoint [4] 300929 0
Baseline, at 4 hours, and at 7 hours.
Secondary outcome [5] 300930 0
Plasma level of cortisol.
Timepoint [5] 300930 0
Baseline, at 4 hours, and at 7 hours.

Key inclusion criteria
Inclusion criteria includes: overweight or obesity (body mass index (BMI) > 25 kg/m2, but < 40 kg/m2) and English-speaking.
Minimum age
45 Years
Maximum age
75 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Exclusion is based on: pregnancy; employment in a non-sedentary occupation; currently watching < 3 hours of television per day; regularly engaged in moderate-intensity exercise = 150 min/week (‘sufficiently active’) for > 3 months; diabetes; use of lipid-lowering medication; known physical activity contraindications, major illness/injury (acute or chronic), cognitive or physical problems that may limit the ability to perform the necessary activity.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Interested volunteers will receive written information about the study in lay terms and a full description of the inclusion/exclusion criteria. After obtaining informed consent and background information, the 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.

Using the randomization schedule, the independent researcher will, after data collection, create a dataset containing outcome, other relevant variables and the random unique code but will not include overt information on the experimental conditions, subject initials, and date of data collection. Data collected under the experimental conditions will be assigned a code (e.g., 0 and 1) unknown to the data analyst and the research team (they would be blinded to the randomization process and condition). Once the data are analysed, the experimental-condition codes will be revealed and the dataset will be checked for errors.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation allocation sequence for will be generated using computer-generated random numbers in a Latin-square experimental design.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Generalized estimating equations will be used to evaluate the differential effects of the trial conditions on the outcomes.

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] 525 0
The Alfred - Prahran
Recruitment postcode(s) [1] 6264 0
3004 - Melbourne

Funding & Sponsors
Funding source category [1] 286664 0
Government body
Name [1] 286664 0
Swedish Council for Working Life and Social Research
Address [1] 286664 0
Box 984
SE-101 37 Stockholm
Country [1] 286664 0
Primary sponsor type
Baker IDI Heart and Diabetes Institute
75 Commercial Road, Melbourne, Victoria 3004 (Postal address: PO Box 6492, St Kilda Road Central, Victoria 8008)
Secondary sponsor category [1] 285442 0
Name [1] 285442 0
Address [1] 285442 0
Country [1] 285442 0

Ethics approval
Ethics application status
Ethics committee name [1] 288733 0
The Alfred Hospital Ethics Committee
Ethics committee address [1] 288733 0
The Alfred Ethics Office, Second Floor, East block, The Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004
Ethics committee country [1] 288733 0
Date submitted for ethics approval [1] 288733 0
Approval date [1] 288733 0
Ethics approval number [1] 288733 0

Brief summary
Recently, data from observational (AusDiab) and experimental (IDLE breaks study) research indicates people who break up their sitting time throughout the day with light-intensity activity (such as light walking) may have better blood glucose and blood fat levels than people who sit for prolonged periods without activity breaks. This experimental study will examine the acute effect of prolonged sitting with and without light intensity activity bouts on memory functions (long-term and short-term memory and executive functions) in adults. Nineteen sedentary overweight/obese adults aged between 45-75 years will be recruited to attend two separate trial days interspersed by a one week washout period: control condition (sitting – 7 hours), a similar duration of sitting but with 3 minute light intensity activity bouts every 30 minutes. Cognitive testing, measurements of neurotrophic, metabolic, inflammatory, cortisol and catecholamine markers will be conducted. The proposed study will provide initial insights into whether breaking up sitting time with intermittent light-intensity activity has the potential for cognitive benefits whilst also describing the acute cognitive effects of prolonged sitting.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 37522 0
Prof David Dunstan
Address 37522 0
Baker IDI Heart and Diabetes Institute
Level 4, 99 Commercial Rd, Melbourne, Victoria 3004
Country 37522 0
Phone 37522 0
+613 8532 1873
Fax 37522 0
+613 8532 1100
Email 37522 0
Contact person for public queries
Name 37523 0
Dr Patrik Wennberg
Address 37523 0
Public Health and Clinical Medicine, Family Medicine Umea University
SE-90187 UMEA
Country 37523 0
Phone 37523 0
+46 90 785 14 23
Fax 37523 0
Email 37523 0
Contact person for scientific queries
Name 37524 0
Dr Patrik Wennberg
Address 37524 0
Public Health and Clinical Medicine, Family Medicine Umea University
SE-90187 UMEA
Country 37524 0
Phone 37524 0
+46 90 785 14 23
Fax 37524 0
Email 37524 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