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Trial registered on ANZCTR

Registration number

ACTRN12613000576729

Ethics application status

Approved

Date submitted

21/05/2013

Date registered

21/05/2013

Date last updated

29/09/2015

Type of registration

Prospectively registered

Titles & IDs

Public title

Breaking up prolonged sitting with walking and brief simple resistance activities for the management of Type 2 Diabetes: The REWARD Study.

Scientific title

Breaking up prolonged sitting with walking and brief simple resistance activities for the management of Type 2 Diabetes: effects on blood glucose and fats.

Secondary ID [1]

None

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Type 2 Diabetes

Condition category

Condition code

Public Health

Health promotion/education

Metabolic and Endocrine

Diabetes

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Twenty four sedentary and injury free participants aged between 35-75 years with diagnosed Type 2 Diabetes (T2D) who are either diet or Metformin controlled will be recruited. A randomized cross-over trial will be used involving three acute experimental conditions (each 8 hours duration) separated by a minimum 6 day washout period. Participants will visit the lab on 5 separate occasions. First, they will attend a standard 120 minute medical screening. Medical examination including a standard glycated haemoglobin (HbA1c) test and cardio-metabolic profiling will verify diabetes status and suitability to participate. Anthropometric measurements (weight, height and waist circumference) will also be obtained. During this visit participants will get the opportunity to practice and become acquainted with the simple (body weight) resistance exercises – half-squats, calf raises and knee raises with gluteal clenches. Participants will also become acquainted with treadmill walking at the required intensity level. Second, a familiarisation session 4-7 days prior to the commencement of the experimental trial, in order to ensure optimal safety and to allow orientation with the testing procedures and measurement devices. During this second visit, participants will be asked to remain seated quietly for about 20 minutes, then complete each activity twice with a 10 minute rest in-between each activity. During this time energy expenditure will be measured using indirect calorimetry (face mask). The three experimental conditions are: (A) Uninterrupted sitting (control condition): Participants will sit quietly in a lounge chair throughout the 8 hr period; (B) Sitting + light-intensity walking breaks: Following baseline measurements and after sitting quietly for 1 hour (steady state) and allowing for consumption of the test meal (20 minutes), 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 a further 11 occasions every 30 min for a total of 36 min of light-intensity activity. Participants will also be fed a lunch meal at around midday; (C) Sitting + simple resistance activities: Identical procedure to condition B, however, 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. This interchange between movements will provide rest for the corresponding muscle groups between each activity segment. To ensure appropriate standardisation, participants will complete each activity in a controlled manner within their range of motion (knee/hip 45 to 90 degrees for half-squats/knee raises), while synchronizing the tempo of each activity to a timer pendulum.

Intervention code [1]

Lifestyle

Intervention code [2]

Behaviour

Intervention code [3]

Prevention

Comparator / control treatment

One day of prolonged sitting without activity breaks: Participants will sit quietly in a comfortable chair for a 8 hour period

Control group

Active

Outcomes

Primary outcome [1]

Blood measurements: Blood samples will be collected every 30 minutes by a trained research nurse. At each occasion, 40 ml blood will be drawn in two separate 20 ml tubes for the analysis of fasting and postprandial glucose and insulin. Plasma glucose, insulin and c-peptide will be sent to a NATA/RCPA accredited independent laboratory. Spare samples will be centrifuged immediately, the plasma removed and frozen immediately (-80 degrees C) for later analysis. One of the 20 ml tubes will be stored for future analysis that is related to this research project.

Timepoint [1]

Every 30 minutes for 7 hours

Secondary outcome [1]

Continuous blood glucose measurement: The CGMS Gold (MiniMed Medtronic, Northridge, CA) will be used for subcutaneous glucose monitoring and consists of a subcutaneous sensor connected to the iPro2 monitor which comes in contact with the interstitial fluid (ISF). The sensor will be inserted onto the lower-back and the device will remain in-situ until the morning after each trial day. A calibration process consisting of 6 finger capillary prick glucose measurements will also be required.

Timepoint [1]

The continuous blood glucose monitor will be worn by participants throughout the duration of each experimental condition, then kept on after the trial until the next morning upon which it will be removed.

Secondary outcome [2]

Blood pressure: Hourly resting brachial arterial blood pressure will be taken after a five minute rest period, three times, at one-minute intervals, using an automated oscillometric blood pressure monitor 10 (Dinamap Vital Signs Monitor 18465X, Criticon, Florida, USA).

Timepoint [2]

Hourly for 8 hours

Secondary outcome [3]

Fatigue: An 18-item Visual Analogue Scale of Fatigue (VAS-f) will be used to assess acute (same day) changes in participant perceptions of fatigue (level of energy) throughout testing. This scale is a commonly used, valid and reliable instrument.

Timepoint [3]

baseline, 2hr, 4hr, 6hr

Eligibility

Key inclusion criteria

Diagnosed with T2D (>=3 months, based on ADA criteria) and are either diet or Metformin controlled; overweight or obese - BMI = 25 kg/m2 but < 40 kg/m2 and English-speaking

Minimum age

35 Years

Maximum age

75 Years

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

HbA1c >=9%; taking insulin or any other oral antihyperglycaemic agents (OHA’s); pregnancy; current smoker; employment in a non-sedentary occupation; currently sitting < 5 hours per day; regularly engaged in moderate-intensity exercise >= 150 minutes/week for > 3 months; known physical activity contraindications, major illness/physical problems (acute or chronic) that may limit their ability to perform the walking and simple resistance activities.

Study design

Purpose of the study

Treatment

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

Crossover

Other design features

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

Our previously published trial with overweight inactive adults demonstrated the efficacy of walking breaks to reduce postprandial glucose (24-30%) and insulin (23%) by a similar magnitude to that which may be observed following a single bout of moderate-intensity cycling in T2D patients. Forecast replication of these findings in the current trial will therefore provide evidence for a novel, lifestyle-based treatment strategy with a degree of efficacy akin to ‘structured exercise’ – an established cornerstone of T2D management. Since insulin iAUC provides key, complementary information alongside our nominated primary endpoint of glucose iAUC, the current trial must be adequately powered to detect changes in both variables. Using the above-mentioned study of walking breaks as the basis for the current study’s sample size requirements, the smallest standardised effect size applies to insulin iAUC (0.84). At 90% power and alpha of 0.05, this dictates a requirement of 18 completions. This sample size would, in turn, detect the anticipated between-condition difference (control vs breaks in sitting) in the primary endpoint (glucose iAUC; effect size=0.93) with 95% power. In our recent trial, we achieved a 15% attrition rate. Thus, as a safeguard, assuming a conservative attrition rate of ~25%, we will randomise 24 participants.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

9/09/2013

Actual

2/10/2013

Date of last participant enrolment

Anticipated

Actual

21/11/2014

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

VIC

Recruitment hospital [1]

The Alfred - Prahran

Recruitment postcode(s) [1]

3004 - Melbourne

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

National Health and Medical Research Council (NHMRC)

Address [1]

National Health and Medical Research Council
GPO Box 1421
Canberra ACT 2601

Country [1]

Australia

Primary sponsor type

Individual

Name

David Dunstan

Address

Baker IDI Heart and Diabetes Institute
Level 4, 99 Commercial road
Melbourne 3004
Victoria
Australia

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

The Alfred Hospital Ethics Committee

Ethics committee address [1]

The Alfred Ethics Office, Second Floor, East block, The Alfred Hospital, 55 Commercial Road, Melbourne, Victoria 3004

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

27/05/2013

Approval date [1]

27/06/2013

Ethics approval number [1]

HREC 257/13

Summary

Brief summary

Sedentary behaviours have become a predominant feature of most adults waking hours. Specifically, prolonged sitting time is now understood to have adverse effects on glycaemic control and other health parameters, adversely impacting on those with Type 2 Diabetes (T2D). Physical activity, including structured resistance exercise, is recommended for the treatment and management of T2D. Resistance activities utilise the larger muscle groups, potentially providing a greater stimulus for glucose uptake; however, many people with T2D may be unable or insufficiently motivated to meet these recommendations. Encouraging recent evidence shows that walking breaks throughout the day are an effective strategy to offset the deleterious effects of prolonged uninterrupted sitting in older, overweight adults. However, these experimental findings are yet to be verified in those with T2D – who could derive the greatest benefit. This study will examine the acute effects of a single bout of prolonged sitting on postprandial blood glucose, insulin and lipids with and without intermittent bouts of light-intensity walking or simple resistance activities in adults with T2D.

Twenty four inactive and injury free participants aged between 35-75 years with diagnosed T2D (longer than 3 months) who are either diet or Metformin controlled will be recruited. Participants will visit the lab on 5 separate occasions. First, they will attend a 120 minute screening and medical exam, then a 60 minute familiarisation session one week prior to the commencement of the experimental trial. During screening, participants will complete a standard Glycated Haemoglobin (HbA1c) test to verify diabetes status (>=6.5%, but <=9%) and will be assessed on their suitability and safety to participate in the study. Familiarisation will ensure they are comfortable with the equipment and exercises, and suitable technique and movement consistency are achieved. The energy expenditure of the two activity breaks will also be measured a this visit. Participants will then complete three experimental conditions in a random order (each 8 hours duration with an initial 1 hour steady-state period) separated by a minimum 6 day washout period. The experimental conditions are: (A) Uninterrupted sitting (control condition): Participants will sit quietly in a lounge chair for 8 hours, with breakfast and lunch provided during this period; (B) Sitting + light-intensity walking breaks: Following baseline measurements and after sitting quietly for 1 hour (steady state) and allowing for consumption of the breakfast meal (20 minutes), participants will complete a 3 min bout of light-intensity walking on the treadmill (level, firm surface, slow pace – 3.2 km.hr-1). They will then return to the seated position. This procedure will be repeated on a further 11 occasions every 30 min (except where a lunch meal is consumed) for a total of 36 min of light-intensity activity; (C) Sitting + simple resistance activities: Identical procedure to condition B, however, 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. This interchange between movements will provide rest for the corresponding muscle groups between each activity segment. To ensure appropriate standardisation, participants will complete each activity in a controlled manner within their range of motion (knee/hip 45 to 90° for half-squats/knee raises). Exercise tempo and correct ‘form’ will be achieved by participants mimicking a pre-prepared video recording, with which they have been previously familiarised. Fasting and postprandial blood samples (glucose/lipids, insulin/C-peptide, incretins, catecholamines and full blood examination) will be measured half-hourly throughout each trial, while blood pressure will be collected at each hour time point. Perceived fatigue will be assessed every 2 hours.

With high volumes of sitting becoming a growing concern, there are potentially important and practical benefits of breaking up sitting time with brief bouts of light intensity activities. This research will provide insights into whether breaking up sitting time with light intensity walking and simple resistance activities has the potential for health benefits in those with T2D. The results of this study have potential to provide more detailed, practical and potentially prescriptive information to help shape clinical and public health approaches in T2D.

Trial website

Trial related presentations / publications

Nil

Public notes

Contacts

Principal investigator

Name

Prof David Dunstan

Address

Baker IDI Heart and Diabetes Institute Level 4, 99 Commercial Rd, Melbourne, Victoria 3004

Country

Australia

Phone

+613 8532 1873

Fax

+613 8532 1100

david.dunstan@bakeridi.edu.au

Contact person for public queries

Name

David Dunstan

Address

Baker IDI Heart and Diabetes Institute Level 4, 99 Commercial Rd, Melbourne, Victoria 3004

Country

Australia

Phone

+613 8532 1873

Fax

david.dunstan@bakeridi.edu.au

Contact person for scientific queries

Name

Paddy Dempsey

Address

Baker IDI Heart and Diabetes Institute Level 4, 99 Commercial Rd, Melbourne, Victoria 3004

Country

Australia

Phone

+61 3 8532-1853

Fax

paddy.dempsey@bakeridi.edu.au

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Breaking up prolonged sitting alters the postprandial plasma lipidomic profile of adults with type 2diabetes.	2017	https://dx.doi.org/10.1210/jc.2016-3926
Embase	Interrupting prolonged sitting in type 2 diabetes: nocturnal persistence of improved glycaemic control.	2017	https://dx.doi.org/10.1007/s00125-016-4169-z

N.B. These documents automatically identified may not have been verified by the study sponsor.

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