None listed
Conditions
Brief summary
The aim of our study is to investigate the effects of a novel intervention - high-intensity aerobic interval training - on aerobic fitness, heart volumes and function, metabolic control, substrate utilization and cardiovascular risk factors among patients with early-onset type 2 diabetes. Diabetes prevalence in Australia is amongst the highest in the developed world and increasingly affects younger people. Early-onset type 2 diabetes mellitus (EOT2D) is a very aggressive form of diabetes - evidenced by poor metabolic control, the appearance of severe cardiovascular disease about three decades earlier than in later-onset type 2 diabetes and early mortality – primarily from cardiovascular causes. Multiple stressors, including management of aggressive diabetes and the burden of obesity and other co-morbidities contribute to impaired quality of life among people with EOT2D. Among adults with later-onset type 2 diabetes, exercise training improves physical fitness, metabolic control, cardiovascular risk factors and quality of life and may reduce early mortality. The gold standard for assessing whole body (aerobic) fitness is peak oxygen uptake (VO2peak) which has both central (heart) and peripheral (skeletal muscle) components. There is a very robust inverse relationship between whole body fitness and mortality: the higher the fitness, the lower the risk of early mortality. The only intervention (other than blood doping which is inherently dangerous) that increases VO2peak is regular aerobic exercise training. However, the only previous study to examine the effects of exercise training in EOT2D found no significant change in whole body fitness or metabolic control after three months of traditional moderate-intensity aerobic exercise training. In contrast to the group with EOT2D, the obese control group without diabetes experienced substantial improvement in whole body fitness. This raises the question of whether a different training strategy would be effective in improving whole body fitness in EOT2D. Randomized controlled trials in older patients groups with cardiovascular disease, e.g. heart failure, demonstrated that an exercise strategy that is novel among people with chronic disease - high intensity aerobic interval training - was safe and was more effective in improving aerobic fitness, heart volumes and function and skeletal muscle capacity than traditional moderate-intensity continuous exercise. Aerobic interval training requires less time than traditional continuous exercise, and thus time-efficiency may render this form of exercise more sustainable for people with chronic disease who are required to cope with many stressors. The proposed study will provide the first evidence of the effects of high intensity aerobic interval training on fitness, metabolic control, heart volumes and function, nerve function and cardiovascular risk among people with early-onset type 2 diabetes.
Interventions
After baseline tests are performed, subjects will be randomised to either the exercise training group or the usual care (exercise advice) group. Exercise training: Subjects randomly allocated to the exercise training group will undertake supervised high-intensity exercise training three times per week for eight weeks. Training will be conducted on a stationary exercise bike, located at either RPA Hospital or a gym close to the subject's home – whichever is more convenient for them. The training physiotherapist or exercise physiologist will supervise each training session and will monitor heart rate and symptom scores. As all sessions are supervised, attendance will be recorded throughout the training period. Participants will wear a heart rate monitor, i.e. sensing strap on their chest, and a watch. In the first week of training, after a 5-min warm-up, cycling at a low load, subjects will do six 30-s efforts on the bike at a heart rate that is about 80-90% of their maximum heart rate. For two minutes between each effort subjects will pedal at an easy load at 60-70% of maximum heart rate. At the end of the session they will pedal at a low load for a 5-minute cool down. The physiotherapist/exercise physiologist will increase the exercise periods to 60 s in the second week of training; and to two minutes for the final 6 weeks of exercise training. Recovery periods between exercise bouts will remain at two minutes. Each exercise training session will therefore only take between 25 to 35 minutes.
Sponsors
A/Prof Alison Harmer
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 45 Years
Healthy volunteers
No
Inclusion criteria
Diagnosis of T2D (two fasting plasma glucose values >7.0 mmol/l and/or a 2-hr value >11.1 mmol/l in an oral glucose tolerance test) aged between 18 and 45 years onset of T2D before age 40 yrs (i.e. early-onset)
Exclusion criteria
chronic respiratory disease; current history of smoking; chest wall disease; heart failure; stroke; overt cardiovascular disease; and any other condition in which exercise is contraindicated, any condition precluding the ability to provide informed consent; pregnancy; and residence > 50 km from the hospital.
Outcome results
None listed