Elucidating the critical role of metabolic stress in central and peripheral mechanisms of adaptation to endurance exercise training in the elderly.

Objectives of the research program: Endurance exercise training aims to improve cardiovascular function by changing how central (i.e., the heart) and peripheral (i.e., the small vessels within the muscles) mechanisms control the transport and distribution of oxygen (O2) to the active muscles. However, this goal is not always as some people do not positively respond to exercise. Although genetic factors might contribute in part to the responsiveness to endurance training, my work shows that all young healthy individuals improve their cardiovascular function when the metabolic stress of exercise is properly quantified. Yet, it remains to be determined whether precise characterization of the metabolic stress would elicit similar responses in the elderly. This is important because the elderly: i) are more likely to experience cardiovascular complications and vascular disease, some of which can be diminished through appropriate endurance training; ii) display a shift of the metabolic boundaries that determine the exercise stress; iii) show different mechanisms of adaptations between females and males. The objective of my research program is to understand the mechanisms that control central and peripheral adaptations to endurance training in the elderly under experimental conditions that accurately quantify metabolic stress. I hypothesize that: i) “non-responders” to exercise do not exist when the appropriate exercise intensity is applied; and ii) central and peripheral adaptations will contribute differently depending on the exercise intensity and the sex of the participant --- Summary of scientific approach: I will perform a 10-week endurance training program with to 4 training groups: 1) Moderate intensity continuous exercise (minimal physical stress); 2) Heavy intensity continuous exercise 1 (small physical stress); 3) Heavy intensity continuous exercise training 2 (large physical stress); 4) High intensity interval training (large physical stress). This model will ensure that the stress of exercise will be different between but identical within groups. Different non- to minimally invasive measures of central and peripheral cardiovascular function will be used to determine the mechanisms responsible for the adaptations in each group --- Novelty and significance: Current approaches are inadequate to prescribe the appropriate stress of exercise to participants. This is a critical limitation that questions the validity of current methods to evaluate the mechanisms that control adaptations to endurance training. Applying a novel exercise model that precisely controls the stress of the exercise, my research program will: 1) demonstrate that cardiovascular adaptations to endurance training are determined by the stress of the intervention; 2) challenge the concept of “non-responders” to exercise. This will make key contributions providing scientists and practitioners working with the elderly with precise information to perform their work more effectively.

Hamad Bin Khalifa University (HBKU)