Exercise oxidative metabolism in children.

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Despite the burgeoning literature in the field of pediatric exercise physiology, knowledge around the factors that regulate oxidative metabolism during exercise in children and adolescents remains elusive. Our understanding of exercise oxidative metabolism in the child has come mainly from studies of maximal oxygen uptake. The transitions in muscular work from rest to exercise in children are best assessed from the pulmonary oxygen uptake (pVO2) kinetic response, which is regulated by oxygen delivery, extraction and utilization. It is possible to use manipulations in work-to-work transitions, pedal cadence and the concentration of inspiratory oxygen to noninvasively examine the influence of upstream (delivery) or downstream (extraction and utilization) components of the oxygen uptake transport chain. Therefore, over the next 5 years, my objectives are to: (1) to elucidate the influence age, sex and maturation have on the pVO2 kinetic response during exercise (2) to identify underpinning peripheral mechanisms by isolating the impact of upstream (delivery) and downstream (utilization) components of the oxygen uptake transport chain (3) in achieving these develop a world-class pediatric ‘exercise oxidative metabolism’ research laboratory at UBC Okanagan SCIENTIFIC APPROACH: Participants will be healthy prepubertal (~8-10 years), pubertal (12 to 16 years) and young adults (18-24 years). To allow for sex differences to be explored all groups will be 50% boys. We will use a number of factorial experiments to explore the pVO2 kinetic response during moderate and heavy intensity exercise transitions (i) with and without priming exercise; (ii) during normoxic (21%) and hypoxic (15%) inspiratory O2 concentrations, and (iii) when pedaling at 55 rpm and at 115 rpm. NOVELTY AND SIGNIFICANCE: This research programme will provide new information about the factors that regulate the oxidative metabolic response to the energetic challenges of exercise in the child, how this differs between girls and boys and how this changes as the child ages and matures. The results from these studies will significantly advance our knowledge of sex-differentiated responses and the influence growth and development have on oxidative function, which has the potential to influence current theories of exercise oxidative metabolism in the child and adolescent. Importantly this work will create a better evidence base from which effective intervention can be designed, establishing the physiologic factors that determine the response to exercise and the degree to which these can be altered. This will be key to developing future research investigating impaired oxidative metabolism due to disease or environment.