Maximal oxidative phosphorylation capacity was clearly reduced in older rats, while mitochondrial efficiency was unaffected.
Circulating nitrate and nitrite concentrations can be augmented by dietary supplementation and this is associated with improved exercise performance and mitochondrial efficiency.
Curiously, the precise cell-non-autonomous and cell-autonomous relevance of endogenous FGF21 action remained poorly understood.We made use of the established UCP1 transgenic (TG) mouse, a model of metabolic perturbations made by a specific decrease in muscle mitochondrial efficiency through increased respiratory uncoupling and robust metabolic adaptation and muscle ISR-driven FGF21 induction.
Fluctuations in cardiorespiratory measures [heart rate (HR), minute ventilation (VE ], thermoregulation [core temperature (CTemp ], and substrate metabolism [muscle contractile efficiency, mitochondrial efficiency] have been associated with changes in RE [3,69-73].
The evidence that chronic use of NaHCO3 coupled with appropriate training may lead to aerobic adaptations associated with improved mitochondrial efficiency in slow-twitch fibres is intriguing [91], and future work may clarify whether this is indeed a viable option for improving aerobic efficiency.
Fly lines with improved mitochondrial efficiency display some of the phenotypes observed in wild-type exercised flies.
Likewise, changes in mitochondrial efficiency and levels of ROS production are thought to underlie lifespan extension via dietary restriction.
Changes in mitochondrial biogenesis and mitochondrial efficiency are thought to be an integral part of the conserved response to exercise in many species [75], [76], [77].
We favor the former possibility, since a genetic model for increased mitochondrial efficiency, the La fly, exhibits potent effects on mobility without any demonstrable effect on cardiac senescence.
We provide evidence that these changes derive, at least in part, from changes in mitochondrial efficiency, and act through mechanisms partially separable from dietary restriction.
