In mitochondrial myopathy patients, high venous oxygen levels can be observed due to poor oxygen utilization.

“I think it a healthy human that's exactly right we have pretty solid matching of oxygen delivery and oxygen utilization but we're talking about patients that have broken mitochondria so this is one of the things that we're at you're trying to investigate one of the ways that Ron Haller at the University of Texas Southwestern Medical Center has proposed diagnosing patients with mitochondrial disease is to put them on a treadmill measure their oxygen extraction and patients with mitochondrial myopathy s will often have high venous oxygen”