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Exercise Science and Sports Medicine Research Unit

Novel ideas and the future research of the unit: Integrative model of exercise physiology

Our model of exercise physiology makes 4 main predictions:

1. that there is never complete muscle recruitment during voluntary exercise in humans;
2. that homeostasis is maintained in all forms of exercise;
3. that fatigue is a symptom that is linked in some way to the maintenance of homeostasis. Thus the greater the "effort' required to maintain homeostasis, the greater the symptoms of fatigue. Indeed the perception of fatigue during exercise rises as a linear function of exercise duration suggesting that, already at the onset of exercise, the brain has calculated for how long it will allow that exercise bout to continue and that it is the achievement of a specific level of fatigue sensations that causes the voluntary termination of exercise; and
4. that the protection of homeostasis during exercise is hard-wired in the brain but can be modified by a number of interventions including training, recent exercise and acute metabolic changes such as exposure to low blood glucose or oxygen concentrations.

The future research of this Unit will aim to do the following:

1. Continue to test the robustness of this model and its ability to predict the exercise response under all conditions of exercise and all threats to the maintenance of homeostasis;
2. Attempt to identify the signals (fatigueogens) that are used by the body in its complex integration of multiple sensory inputs that determine the extent of skeletal muscle recruitment (pacing strategy) that is adopted during exercise. The variables that we presently have the capacity to study include heat, cold, carbohydrate intake before and during exercise, other interventions (such as dietary interventions) that modity the metabolic and hormonal response during exercise, exposure to different concentrations of gasses (oxygen, carbon dioxide, helium) in the inspired air, and the effects of different human diseases.
3. identify the brain mechanisms involved in this complex integration. In this way, the focus of the research will likely lead to the development of a major research thrust in neurophysiology and the engineering principles of complex systems and their control.