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Trial registered on ANZCTR


Registration number
ACTRN12616000574448
Ethics application status
Approved
Date submitted
19/04/2016
Date registered
3/05/2016
Date last updated
2/07/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
High-intensity interval training and hypoglycaemia minimisation in adults with type 1 diabetes
Scientific title
High-intensity interval training and hypoglycaemia minimisation in adults with type 1 diabetes
Secondary ID [1] 289045 0
none
Universal Trial Number (UTN)
Trial acronym
HIIT HYPO T1D
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 1 diabetes 298470 0
Condition category
Condition code
Metabolic and Endocrine 298565 298565 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Study participants will have initial baseline cardiorespiratory fitness testing on a cycle ergometer and an exercise protocol familiarisation session in the Charles Perkins Centre (CPC) gym. Participants will wear a FreeStyle Libre Pro flash glucose monitor for the entire duration of the study. The glucose recordings on the FreeStyle Libre Pro flash glucose monitor remain masked to the participant for the entire duration of the study. The FreeStyle Libre Pro flash glucose monitor data is subsequently downloaded and used in analysis. Participants will be advised to continue routine fingerprick glucose testing, such as premeals, post-meals and at bedtime. They will have a baseline overnight continuous glucose recording with FreeStyle Libre Pro flash glucose monitor (with no exercise in the preceding 2 days) on their usual insulin regimen.

Participants will undertake a total of 4 exercise intervention sessions within 4 weeks of wearing a flash glucose monitor, with at least 2 days between exercise sessions. All exercise sessions will be supervised by a study investigator, thus ensuring adherence to the intervention and achievement of target exercise intensity. Participants will be randomised to complete either the HIIT series (3 sessions) or continuous exercise (1 session) first in a cross-over design. Participants will be asked to avoid caffeine, alcohol and exercise for 24hours prior to each exercise intervention session. Participants will follow their usual home diet and insulin routine on the day of each exercise intervention session, and will arrive at the Charles Perkins Centre Gym at 4pm (at least 2 hours after lunch with usual insulin bolus) to commence the supervised exercise session. They will then go home and have dinner with 75% of their usual insulin:carb bolus and 75% of their usual correction insulin dose if needed. Participants will be asked to have a similar dinner on all exercise days. At 9pm on intervention exercise nights, all participants will consume a 15gram carbohydrate-containing snack (with 75% of their usual insulin bolus and 75% of their usual correction if they would usually bolus for snacks) before bed, and instructed to ensure blood glucose is>7.0 mmol/L before bed, with consumption of extra carbohydrate intake to achieve this if required.

HIIT exercise intervention session:
High intensity interval training (HIIT) exercise will consist of 33minutes of supervised exercise on a cycle ergometer: After 5minutes of warm-up at approximately 60% peak heart rate, participants will do 4 bouts of 4-minute high-intensity intervals at 85-95% peak heart rate interspersed with 3 bouts of 3-minute recovery intervals at 50-70% peak heart rate. The exercise session will conclude with 3minutes of cool-down at approximately 50% peak heart rate. That night, the participant will administer basal insulin at 10% reduction, 20% reduction or 30% reduction of their usual dose (HIIT10, HIIT20, HIIT30 intervention sessions respectively).
Intervention code [1] 294529 0
Treatment: Other
Comparator / control treatment
Continuous moderate intensity aerobic exercise will consist of 41minutes of supervised exercise on a cycle ergometer: After 5minutes of warm-up at approximately 60% peak heart rate, participants will do 33minutes cycling at 60-70% peak heart rate. The exercise session will conclude with 3minutes of cool-down at approximately 50% peak heart rate. This continuous moderate intensity aerobic exercise session has a similar energy expenditure to the HIIT exercise session. That night, the participant will administer basal insulin at 20% reduction of their usual dose.

Participants will also have a baseline overnight continuous glucose recording (with no exercise in the preceding 2 days) on their usual insulin regimen.
Control group
Active

Outcomes
Primary outcome [1] 298051 0
Total duration (minutes) of overnight hypoglycaemia following afternoon HIIT exercise with varying basal insulin-dose reductions of 10%, 20% and 30% (HIIT10, HIIT20, HIIT30) compared to continuous moderate-intensity aerobic exercise with basal insulin-dose reduction of 20% (Cont20) and non-exercise baseline with no basal insulin-dose reduction. This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [1] 298051 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [1] 323021 0
Overnight mean glucose (mmol/L)
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [1] 323021 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [2] 323022 0
% glucose in target range 4.0-10.0mmol/L.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [2] 323022 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [3] 323023 0
Number of episodes of hypoglycaemia/night.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [3] 323023 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [4] 323024 0
Mean duration of hypoglycaemic episodes (minutes).
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [4] 323024 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [5] 323025 0
% glucose in hypoglycaemic range.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [5] 323025 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [6] 323026 0
Glucose nadir (mmol/L).
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [6] 323026 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [7] 323027 0
Area under the curve for glucose less than or equal to 3.9mmol/L.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [7] 323027 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [8] 323028 0
Number of episodes of hyperglycaemia/night.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [8] 323028 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [9] 323029 0
Mean duration of hyperglycaemic episodes (minutes).
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [9] 323029 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [10] 323030 0
% glucose in hyperglycaemic range.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [10] 323030 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [11] 323031 0
Glucose peak (mmol/L)
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [11] 323031 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [12] 323032 0
Glucose variability - interquartile range.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [12] 323032 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [13] 323033 0
Glucose variability - Standard deviation.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [13] 323033 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [14] 323034 0
Glucose variability - coefficient of variation.
This will be measured using data from the Freestyle Libre Pro Flash glucose monitor.
Timepoint [14] 323034 0
Overnight non-exercise baseline, and overnight after each afternoon exercise session.
Secondary outcome [15] 325791 0
Systolic blood pressure (mmHg). This will be measured using a sphygmomanometer on the upper arm.
Timepoint [15] 325791 0
Before the start of exercise, and 4 times during the exercise session (during each of the 4 bouts of high-intensity intervals in the HIIT10 session, and 4 times over the continuous exercise session Cont20), and after finishing the exercise sessions (HIIT10 and Cont20).
Secondary outcome [16] 325792 0
Diastolic blood pressure (mmHg). This will be measured using a sphygmomanometer on the upper arm.
Timepoint [16] 325792 0
Before the start of exercise, and 4 times during the exercise session (during each of the 4 bouts of high-intensity intervals in the HIIT10 session, and 4 times over the continuous exercise session Cont20), and after finishing the exercise sessions (HIIT10 and Cont20).
Secondary outcome [17] 325793 0
Augmentation index (%). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [17] 325793 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [18] 325794 0
Augmentation index calculated for a heart rate of 75 beats per minute (%). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [18] 325794 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [19] 325795 0
Pulse wave velocity (m/s). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [19] 325795 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [20] 325796 0
Pulse transit time (seconds). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [20] 325796 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [21] 325797 0
Aortic systolic pressure (mmHg). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [21] 325797 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [22] 325798 0
Aortic diastolic pressure (mmHg). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [22] 325798 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [23] 325799 0
Aortic mean arterial pressure (mmHg). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [23] 325799 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.
Secondary outcome [24] 325800 0
Aortic pulse pressure (mmHg). This will be measured using non-invasive applanation tonometry (SphygmoCor XCEL PWA and PWV System).
Timepoint [24] 325800 0
Cont20 and HIIT10 exercise sessions; before exercise, immediately after exercise, and 30 and 60 minutes post-exercise.

Eligibility
Key inclusion criteria
Age 18-70 years,T1D > 1 year duration, HbA1c 6.5-10.0%, Self-manage diabetes with multiple-daily insulin injections including a daily nocte dose of basal insulin or twice-daily basal insulin, or subcutaneous insulin pump.
Minimum age
18 Years
Maximum age
70 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Conditions which prevent participation in the exercise intervention sessions on cycle ergometer (such as arthritis, unstable cardiac condition, active foot ulcer, untreated severe retinopathy), pregnancy.

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)
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
Crossover
Other design features
Phase
Type of endpoint(s)
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 5639 0
Royal Prince Alfred Hospital - Camperdown

Funding & Sponsors
Funding source category [1] 293417 0
Hospital
Name [1] 293417 0
Sydney Local Area Health District
Address [1] 293417 0
Royal Prince Alfred Hospital
Missenden Road
Camperdown NSW 2050
Country [1] 293417 0
Australia
Primary sponsor type
Hospital
Name
Sydney Local Area Health District
Address
Royal Prince Alfred Hospital
Missenden Road
Camperdown NSW 2050
Country
Australia
Secondary sponsor category [1] 292242 0
None
Name [1] 292242 0
Address [1] 292242 0
Country [1] 292242 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294864 0
Royal Prince Alfred Hospital Human Ethics Review Committee
Ethics committee address [1] 294864 0
c/- Research Ethics and Governance Office (REGO)
Royal Prince Alfred Hospital
Missenden Road
CAMPERDOWN NSW 2050
Ethics committee country [1] 294864 0
Australia
Date submitted for ethics approval [1] 294864 0
27/04/2016
Approval date [1] 294864 0
14/07/2016
Ethics approval number [1] 294864 0
Protocol No X16-0159 & HREC/16/RPAH/198

Summary
Brief summary
High-intensity interval training (HIIT) characterises many team and field sports (eg. basketball and soccer) and spontaneous play in children. It involves alternating periods of high-intensity exercise and periods of recovery. Exercise-induced hypoglycaemia and increased glucose variability are barriers to exercise participation in many people with Type 1 diabetes (T1D). Trials of single-session HIIT generally show that blood glucose decreases to a smaller extent during HIIT compared to continuous aerobic exercise, suggesting that HIIT may be a preferred form of exercise for people with T1D.

Overnight basal insulin reduction can reduce the risks of nocturnal hypoglycaemia following afternoon continuous moderate-intensity aerobic exercise in children with type 1 diabetes. Guideline recommendations for preventing post-exercise nocturnal hypoglycaemia after HIIT are generally based on those for continuous aerobic exercise, however it is unclear whether these two exercise types can be treated similarly. The effects of a basal insulin rate reduction to prevent nocturnal hypoglycaemia after HIIT has not been systematically studied.

To our knowledge, this study will be the first study to investigate the effects of different dose-reductions in basal insulin to reduce the risks of overnight hypoglycaemia after high-intensity interval training in adults with type 1 diabetes, in comparison to non-exercising control day, and continuous moderate-intensity aerobic exercise. This will allow evidence-based recommendations to be developed to allow adults with type 1 diabetes to safely undertake HIIT exercise with reduced hypoglycaemia risk.

Primary Objective:
To determine appropriate dose-reduction in basal insulin to minimise overnight hypoglycaemia and hyperglycaemia following afternoon HIIT exercise

Hypothesis: An evening basal insulin dose reduction of 20% will similarly minimise hypoglycaemia, and result in the greatest % of glucose in target 4-10mmol/L overnight, compared to 10% reduction and 30% reduction.

Secondary Objective:
To compare glucose response to single-session HIIT compared to single-session continuous moderate-intensity aerobic exercise.

Hypothesis: HIIT with 20% basal dose reduction will be associated with a similar duration of overnight hypoglycaemia and glucose nadir compared with continuous moderate-intensity aerobic exercise of similar energy expenditure with 20% basal dose reduction.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 65274 0
Prof Stephen Twigg
Address 65274 0
Level 3W, Charles Perkins Centre D17
John Hopkins Drive
The University of Sydney
NSW 2006
Country 65274 0
Australia
Phone 65274 0
+612 8627 1890
Fax 65274 0
Email 65274 0
stephen.twigg@sydney.edu.au
Contact person for public queries
Name 65275 0
Dr Angela Lee
Address 65275 0
Level 3W, Charles Perkins Centre D17
John Hopkins Drive
The University of Sydney
NSW 2006
Country 65275 0
Australia
Phone 65275 0
+612 8627 1890
Fax 65275 0
Email 65275 0
alee8473@uni.sydney.edu.au
Contact person for scientific queries
Name 65276 0
Prof Stephen Twigg
Address 65276 0
Level 3W, Charles Perkins Centre D17
John Hopkins Drive
The University of Sydney
NSW 2006
Country 65276 0
Australia
Phone 65276 0
+612 8627 1890
Fax 65276 0
Email 65276 0
stephen.twigg@sydney.edu.au

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