Lipid Metabolism During Exercise

• A substantial portion of energy production during prolonged light or moderate exercise comes from fatty acid oxidation in the muscles– The increased energy requirement of sustained low to

moderate intensity exercise increases lipolysis with rise in FA mobilization and the uptake and oxidation of NEFA.

– High intensity exercise results in a decreased FA utilization and more reliance on CHO sources

• Low to moderate intensity exercise is dependent on fat utilization

• As intensity increases, there’s less dependence on fat and more on CHO

Optimal Intensity

• The increased energy requirement of sustained moderate intensity exercise induces an increase in lipolysis with a four to tenfold increase in FA mobilization – 40-70% VO2max (Ahlborg et al., 1974)

Lipid Metabolism During Recovery

• Moderate to high intensity exercise lead to lipid utilization during recovery when energy expenditure is matched.(Kuo, 2005)

- resynthesis of glycogen during recovery

- increase in lipid oxidation for energy,

while sparing CHO to restore glucose

homeostasis and glycogen repletion.

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Effects of Resistence Training on Lipolysis during Subsequent

Submaximal Exercise• Fat metabolism

during submaximal exercise is strongly effected by prior resistance exercise– Enhanced Fat

availability– RE20 vs. RE120

Repeated bouts of aerobic exercise

• Markedly higher lipid mobilization during repeated exercise bout– Enhanced lipolyitic response in Ex2– Epinephrine & Norepinephrine– Insulin