None listed
Conditions
Brief summary
The incidence of type 2 diabetes mellitus (T2DM) is growing rapidly, in part because of the aging population, sedentary lifestyle and diet habits. In 2010, an estimated 257 million people worldwide had T2DM, representing an important global public health issue. Non-healthy diet is commonly accompanied by consumption of sugar-sweetened beverages (SSB), reported to provide little (if any) other nutrition or health benefit. The last 2010 National Nutrition Survey in Australia found that 58% of young adults drink an average of 2.1 cans per day (800mL), which is the first everyday source of sugar. In this context, several studies reported in children and adults high correlation between SSB consumption and risk to develop T2DM due to its effects on weight gain and glucose metabolism. These drinks represent 70 to 120g of sugar per litre and lead to acute transient hyperglycaemia (high level of glucose in blood), reported as a precursor of insulin-resistance but also responsible of endothelial dysfunction in the whole arterial tree. The endothelium is the thin layer of cells that lines the interior surface of heart and blood vessels and helps to control blood pressure through vasodilation and vasoconstriction, the widening and constricting of the blood vessels respectively. However, very few studies have investigated the underlying mechanisms involved in endothelial dysfunction in response to SSB -induced acute hyperglycemia. Briefly, endothelial dysfunction in this context has been demonstrated as an impairment of the capacity of blood vessels vasodilation, probably associated with a reduction in nitric oxide (NO) synthesis or biodisponibility. Previous results from our team has reported for the first time in cutaneous microcirculation the implication of oxidative stress and lower activity of endothelial nitric oxide synthase (eNOS, which is responsible of NO synthesis) in endothelial dysfunction after an acute hyperglycemia in healthy rats. On the top that, our works and other demonstrated that patients with T2M or patients in pre-diabetic state (obese or metabolic syndrome) have chronic NO related endothelial dysfunction even without environmental stress. Thus, the first objective of the present study is to explore the effect of SSB consumption on endothelial function in large as well as in small vessels in healthy and T2M subjects, with a focus on underlying mechanisms of the NO pathway. To improve cardiovascular dysfunction in several diseases, physical exercise is a well-known non pharmacological strategy. The higher antioxidant status in cardiovascular and muscular tissues are likely to account for the positive effects of this strategy for disease prevention or rehabilitation. Physical Exercise exercise training is also reported to improve the NO pathway with higher eNOS expression. Thus, the second objective of the present work will be to investigate the potential preventive effects of physical activity on endothelial dysfunction following acute hyperglycemia in healthy and T2DM participants.
Interventions
We propose a randomized crossover design study to investigate micro-circulatory endothelial and smooth muscle cell function in response to sugary drink, insulin resistance and combinations of these factors with physical activity in healthy and type 2 diabetes (T2D) participants.
Microvascular investigation will be performed before and after a 12-week exercise program (see details below). Participants will present to the laboratory following overnight fasting. All measurements will be taken befo
We propose a randomized crossover design study to investigate micro-circulatory endothelial and smooth muscle cell function in response to sugary drink, insulin resistance and combinations of these factors with physical activity in healthy and type 2 diabetes (T2D) participants. Microvascular investigation will be performed before and after a 12-week exercise program (see details below). Participants will present to the laboratory following overnight fasting. All measurements will be taken before (baseline) and 15 min after sugary drink ingestion (65 g of sugar for a 600 mL drink to challenge vascular function) or placebo drink in a randomized order for each volunteer (5 days between consumption of both drinks). A period of 15 min after drink ingestion is chosen because pilot research demonstrated that plasma glucose and insulin concentrations reach peak values within 15–30 min after glucose loading via sugary drink ingestion. In the week following pre-intervention microvascular measurements, participants will begin a 12-week vigorous exercise program in-line with ESSA guidelines (Hordern et al., 2012). T2D participants will be randomized into two groups identified as Group 1 and Group 2. Initially, Group 2 (control) participants will not participate in any physical activity outside of usual activities of daily living, whilst Group 1 will participate in a 12 week vigorous exercise program. To achieve the minimum of 125 minutes vigorous exercise per week, participants will attend three supervised 60 minute training sessions per week in small group sessions (up to 5 participants). Each training session will be comprised of vigorous aerobic training and resistance exercises and administrated all time by an exercise physiologist. Sessions will include a 10 minute warm up period at 60-70% peak heart rate on the Monark Cycle. The main exercise session will begin with 20 minutes of a whole-body resistance training circuit. Participants will spend 45 seconds at each station and a have a maximum of 15 seconds to move between the 5 stations. Resistance will be set at the participant’s individual 10 maximal repetition (RM). Each participant’s 10RM will be determined in the week prior to the intervention. Resistance will be adjusted throughout the intervention by use of a rating of perceived exertion (RPE). Following the resistance training circuit, participants will perform a 22 minute bout of continuous cycling at 80% peak heart rate. Participants will wear heart rate monitors to achieve the assigned exercise intensity.
Sponsors
Australian Catholic University
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Educational / counselling / training
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
60 participants aged 18-65 years old will be recruited: 30 healthy sedentary (< 2 hours of scheduled physical activity per week) controls, and 30 sedentary T2D patients. Participants will be matched on age, sex and BMI of T2D participants, to focus on the specific effect of T2D.
Exclusion criteria
Participants will be excluded based on any of the following: cardiovascular disease or history, smoking, more than 5% weight gain or loss in the last 6 months; or use of vasodilator medication.
Outcome results
None listed