Does Estrogen Blunt the Effects of Exercise Training on Glycemic Control

Previous research has found that males and females respond differently to exercisetraining, particularly with respect to improvements in blood sugar control and immunesystem health. This is crucial since insulin resistance, which can lead to type 2diabetes and other health problems, affects millions of Canadians. People with insulinresistance often have higher inflammation. Exercise is known to improve insulinresistance and reduce inflammation, but females seem to benefit less from exercisecompared to men. The investigators believe this difference might be due to estrogen, ahormone that helps regulate blood sugar (in non‐exercising conditions) and reduceinflammation. Females have higher estrogen levels, which might explain their ability toregulate resting blood sugar control and also immune function at rest. Our research willinvestigate how estrogen influences the acute and chronic effects of exercise males. Theinvestigators will study how estrogen influence's the body's response to exercise,particularly in terms of reducing inflammation and improving blood sugar levels as wellas immune function. Overweight and obese males will undergo 2 weeks of high intensityinterval training while taking either an estrogen supplement or placebo. Prior to andfollowing training males will undergo an assessment of maximal fitness (VO2max test) andan oral glucose tolerance test. Prior to and following the acute exercise test bloodsamples will be taken to determine the acute effects of exercise on immune cell functionand inflammation. Prior to and during the oral glucose tolerance test participants willhave blood samples taken to determine glucose handling and insulin sensitivity. They willalso have a muscle biopsy taken prior to and 1h into the oral glucose tolerance test todetermine the effects of estrogen supplementation on insulin signaling, mitochondrialcontent and function, fat metabolism and fat storage in skeletal muscle.