TY - JOUR

T1 - Regulation and limitations to fatty acid oxidation during exercise

AU - Jeppesen, Jacob

AU - Kiens, Bente

N1 - CURIS 2012 5200 025

PY - 2012

Y1 - 2012

N2 - Fatty acids (FA) as fuel for energy utilization during exercise originate from different sources: FA transported in the circulation either bound to albumin or as triacylglycerol (TG) carried by very low density lipoproteins (VLDL) and FA from lipolysis of muscle TG stores (IMTG). Despite a high rate of energy expenditure during high intensity exercise the total fatty acid oxidation is suppressed to below that observed during moderate intensity exercise. Although this has been known for many years, the mechanisms behind this phenomenon are still not fully elucidated. A failure of adipose tissue to deliver sufficient fatty acids to exercising muscle has been proposed, but evidence is emerging that factors within the muscle might be of more importance. The high rate of glycolysis during high intensity exercise might be the "driving force" via the increased production of acetyl CoA which in turn is trapped by carnitine. This will lead to less availability of free carnitine for fatty acid transport into mitochondria. This review summarizes our present view on how FA metabolism is regulated during exercise with a special focus on the limitations in FA oxidation in the transition from moderate to high intensity exercise in humans.

AB - Fatty acids (FA) as fuel for energy utilization during exercise originate from different sources: FA transported in the circulation either bound to albumin or as triacylglycerol (TG) carried by very low density lipoproteins (VLDL) and FA from lipolysis of muscle TG stores (IMTG). Despite a high rate of energy expenditure during high intensity exercise the total fatty acid oxidation is suppressed to below that observed during moderate intensity exercise. Although this has been known for many years, the mechanisms behind this phenomenon are still not fully elucidated. A failure of adipose tissue to deliver sufficient fatty acids to exercising muscle has been proposed, but evidence is emerging that factors within the muscle might be of more importance. The high rate of glycolysis during high intensity exercise might be the "driving force" via the increased production of acetyl CoA which in turn is trapped by carnitine. This will lead to less availability of free carnitine for fatty acid transport into mitochondria. This review summarizes our present view on how FA metabolism is regulated during exercise with a special focus on the limitations in FA oxidation in the transition from moderate to high intensity exercise in humans.

U2 - 10.1113/jphysiol.2011.225011

DO - 10.1113/jphysiol.2011.225011

M3 - Review

C2 - 22271865

VL - 590

SP - 1059

EP - 1068

JO - The Journal of Physiology

JF - The Journal of Physiology

SN - 0022-3751

IS - 5

ER -