None listed
Conditions
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.
Interventions
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 subseq
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).
Sponsors
Sydney Local Area Health District
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
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.
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.
Outcome results
None listed