The Role of Exercise Intensity in the Understanding of Metabolic Flexibility in Healthy Lean, Overweight and Obese Individuals

INTERVENTION: Participants will be asked to perform exercise tests during two testing sessions. One exercise test will involve a single bout of cycle ergometer exercise at 80% (HI) VO2max for 38 minutes which expends 400 kcal). This is a crossover study with the order of the exercise tests being randomised. The second test will occur a minimum of 1 week following the commencment of first exercise test (maximum of up to 4 weeks). This washout period will be based on participant availability, work place availability, and human physiology (ie: females will be asked to perform exercise trials only within the proliferative phase of their menstral cycle). CONDITION: Metabolic Flexibility Overweight and Obesity PRIMARY OUTCOME: Identify key differences in cellular pathways involved in energy metabolism at rest and following an acute bouts of exercise between healthy lean, overweight and obese individuals by using metabolomic technologies to analysis serum and muscle samples, and genomic technologies to examine genetic differences. SECONDARY OUTCOME: Nil INCLUSION CRITERIA: Participants will be considered relatively healthy lean, overweight and obese individuals. Participants will be included if they have adequate glucose handling (no diagnosed diabetes, fasting blood glucose must be less than 7.0 mmol/L), not performing any regular fitness training (i.e. greater than 30 minutes, 3 times per week) for the past 6 months, not taking contraindicated prescription medication (i.e. thyroid, hyperlipidmeic, hypoglycemic, or antihypertensive), non‐pregnant, not peri‐ or post‐menopausal, must have physician approval (overweight and obese participants only), and not current involvement in other research studies.