Exercise training strategies to optimize muscle oxygen uptake, muscle oxidative capacity and performance in humans

• My research area focuses on studying the entire O2 cascade in humans from lungs to mitochondria with an integrative approach.The overall aim of the PhD project is to examine in detail 1) the differences in convective O2 delivery (Fick method) and mitochondrial function (high resolution respirometry technique) between individuals with low and high VO2 max, 2) to quantify the effect of aerobic interval training with elevated O2 delivery on circulatory, muscle mitochondrial components on VO2 max in highly trained individuals, as well as, 3) to quantify the effect of elevated O2 delivery on circulatory and metabolic responses (blood flow and muscle VO2) to exercise engaging small and large muscle groups. A specific focus of the PhD project is to examine and quantify how differences in a) mitochondrial OXPHOS capacity and b) mitochondrial O2 affinity (p50) define differences in muscle O2 extraction and muscle VO2 between individuals of low fitness and those with high aerobic endurance capacity. Although a vast body of literature supports a strong link between muscle oxidative capacity and peak VO2 during exercise, almost all studies are correlative, and the dependence and contribution of mitochondrial capacity to muscle VO2 has yet to be quantified. To this end, experiments are designed to control for O2 transport during exercise as the independent variable between groups with high and low aerobic capacities. The effect of aerobic interval training with elevated O2 delivery on central (circulatory) and peripheral (muscle oxidative) mechanisms for elevating peak VO2 and endurance performance are explored in endurance-trained individuals. Hyperoxic air increases O2 dissolved in the blood, elevates arterial O2 saturation, and increases arterial O2 concentration, resulting in a higher O2 delivery to the working muscle independently from blood flow. Since mitochondria have an excess oxidative capacity in relation to O2 delivery during whole body exercise in normoxia, we hypothesize that mitochondrial volume, function and O2 affinity as well as endurance performance are largely improved following endurance interval training with elevated O2 delivery compared to normoxia.Our preliminary data show that OXPHOS and performance are significantly enhanced following six weeks of periodized aerobic interval training. Significantly differences in performance but not in OXPHOS are found when training is conducted in hyperoxia compared to normoxia.

Nyckelord

mitochondria

OXPHOS

Hyperoxia

Medicin/Teknik

Medicine/Technology

Publikations- och innehållstyp

vet (ämneskategori)

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