Archive for the ‘mitochondria’ Category

A Must Read

February 5, 2009

When possible, it’s always better to read the original paper rather than just the abstract. Here’s a link to a must read paper on endurance by JO Holloszy and EF Coyle. Taken by itself, it could provide fuel for the ‘more is better’ approach, but remember to take everything with a grain of salt. After all, we are people, not rats, and there’s more to life than the number of mitochondrial enzymes in your quadriceps.

Here’s the abstract

Regularly performed endurance exercise induces major adaptations in skeletal muscle. These include increases in the mitochondrial content and respiratory capacity of the muscle fibers. As a consequence of the increase in mitochondria, exercise of the same intensity results in a disturbance in homeostasis that is smaller in trained than in untrained muscles. The major metabolic consequences of the adaptations of muscle to endurance exercise are a slower utilization of muscle glycogen and blood glucose, a greater reliance on fat oxidation, and less lactate production during exercise of a given intensity. These adaptations play an important role in the large increase in the ability to perform prolonged strenuous exercise that occurs in response to endurance exercise training.

Interesting article by Kirk Willet

February 5, 2009

This article by Kirk Willet has been around for a few years, but still merits a read.

This result suggests that mitochondrial density adaptations can be achieved in a reasonably duration independent manner (Dudley et al., 1982).  The overall higher mitochondrial densities associated with the higher intensities outlines the potential need for mitochondrial uncoupling and the AMPK signaling, at least beyond the completely untrained state.

-Kirk Willet