None listed
Conditions
Brief summary
Microvessels are the smallest type of blood vessels inside every organ of the human body. They are approximately the size of a human hair, or smaller. There are approximately 100,000 km of these microvessels in humans and they are crucial for human health and wellbeing, as they are responsible for maintaining tissue nutrition including the delivery and exchange of oxygen. Microvessels are capable of undergoing structural and functional change during growth and development and they respond and/or adapt to stimuli including heating and exercise. Microvessels may become dysfunctional, causing symptoms that affect the skin, kidneys, eyes, muscles, nerves, heart and brain. These microvessel diseases are particularly common in people with cardiovascular diseases, obesity and diabetes. However, at present, we know very little about microvessel function and health in humans due to the lack of direct and reliable imaging methods. The aim of this study is to use optical coherence tomography (OCT) techniques to quantify and compare the effect of exercise training and repeated body heating on the health and function of skin microvessels in individuals with T2D, and in older overweight and obese persons. We will also measure artery function in large arteries in the limbs and the brain, alongside heart function, to determine which of these factors impact on microvessel function. The exercise training will consist of 3x per week aerobic training (i.e. cycling/fast-paced walking) for 40 minutes during 12 weeks. There will be two centre-based and one home-based exercise session per week. Centre-based sessions will consist of cycling at range from 60 to 75% of individuals' maximum heart rate, depending on the exercise block, with less intense warm-up and cool down periods. Home-based sessions will consist of a fast-paced walking also meeting the desired heart rate training zone (60-75% of maximum hear rate). The heat therapy will be fully centre-based and will consist of 3 session per week, with a duration of 40 minutes each session, for 12 weeks. Individuals will remain in a hot tube at 40°C for 40 minutes.
Interventions
Individuals will be randomised to one of four groups:
1. aerobic exercise training,
2. heat therapy,
3. aerobic exercise plus heat therapy, or
4. a control group who will be requested to maintain their usual lifestyle and activities, for a 12-week intervention period.
The aerobic exercise training involves 2 x 40-minute centre-based cycling, plus 1 x 40-minute home-based sessions (i.e. moderate-intensity aerobic training) per week for 12 weeks, with each session composed of 5 minutes of war
Individuals will be randomised to one of four groups: 1. aerobic exercise training, 2. heat therapy, 3. aerobic exercise plus heat therapy, or 4. a control group who will be requested to maintain their usual lifestyle and activities, for a 12-week intervention period. The aerobic exercise training involves 2 x 40-minute centre-based cycling, plus 1 x 40-minute home-based sessions (i.e. moderate-intensity aerobic training) per week for 12 weeks, with each session composed of 5 minutes of warmup, 30 minutes of aerobic exercise, and 5 minutes cooldown. Exercise intensity will change every 4 weeks, considering individuals adaptation to exercise and intensity. During the first 4 weeks, for familiarisation purposes, exercise intensity will be established at 60-65% of their maximum heart rate. For the following 4-week block, intensity will be established at 65-70% of their maximum heart rate. For the last 4-week block, exercise intensity will be established at 70-75% of their maximum heart rate. Five-minute warm-up period will be kept at 50-55% of individuals maximum heart rate throughout the whole exercise program. Regarding cool-down, individuals will maintain the exercise stimulus for 5 minutes in a very light intensity. Maximum heart rate will be determined via a maximal oxygen uptake (VO2max) exercise test. The exercise program will be individually prescribed by an Accredited Exercise Physiologist/Scientist, using individuals' maximal heart rate to match exercise intensity. Centre-based sessions will take place at The University of Western Australia (UWA) School of Human Sciences (Exercise and Sport Science) gymnasium and will be monitored by an experienced exercise physiologist/researcher. The centre-based exercise sessions will be provided in groups of five participants, whereas they will be constantly monitored by a physiologist/researcher. The home-based exercise sessions will consist of a fast-paced walking/jogging at the same heart rate zone as the centre-based exercise sessions. Individuals will be given a heart rate monitor in order to keep heart rate at the desired intensity. Adherence will be checked via session attendance checklist. The two heat therapy groups will attend The University of Western Australia (UWA) School of Human Sciences (Exercise and Sport Science) every week for 12 weeks, for 3 x 40 minute sessions per week of heat therapy. The heat therapy will be via water immersion for 40 minutes in order to increase body core temperature and induce reflex blood flow changes in skin blood flow and sweating. Individuals will be immersed up to the shoulder level in a 40°C hot tub for 30 minutes. Sequentially, individuals will be positioned in a fashion that the water level reaches waist-level for another 10 minutes. Heat therapy sessions will be supervised by an exercise physiologist/researcher, and will be provided in small groups of five. Adherence will be monitored via session attendance checklist. Individuals with type 2 diabetes and obesity will be enrolled, randomized and assessed together.
Sponsors
The University of Western Australia
Study design
Allocation
Randomised controlled trial
Intervention model
Factorial
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
45 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
Age range between 45 and 70 years old; BMI greater than 30 kg/m² or BMI 27-30 kg/m² with at least one established weight-related cardiometabolic co-morbidity, or type 2 diabetes diagnosis >1 year.
Exclusion criteria
Type 2 diabetes diagnosis <1 year Insulin and/or sulphonylurea medication Glycated haemoglobin >8.5 Advanced microvessel complications including ulceration, decrease kidney function and/or eye complications which require treatment Macrovascular complications including a history of unregulated high blood pressure, myocardial infarction and/or cerebrovascular disease.
Outcome results
None listed