None listed
Conditions
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.
Interventions
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 sittin
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.
Sponsors
Professor David Dunstan
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
25 Years to 65 Years
Healthy volunteers
No
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.
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.
Outcome results
None listed