Near-infrared Spectroscopy of Vastus Lateralis Muscle during Incremental Cycling Exercise in patients with Type 2...

It is clinically important to elucidate the precise mechanism of exercise intolerance in patients with type 2 diabetes (T2DM). The aim of this study was to examine whether there is a difference in the time course change of the oxygenation in the vastus lateralis (VL) muscle during submaximal incremental cycling exercise between patients with T2DM and age-matched healthy subjects.

Nine elderly men with T2DM and 10 age-matched healthy men (CON) participated in this study. All participants performed an incremental cycling exercise.Total, deoxygenated and oxygenated hemoglobin/myoglobin in the VL muscle were assessed using near-infrared spectroscopy, and cardiorespiratory response was also evaluated during the exercise.

There were no significant differences in the time course changes of deoxygenated hemoglobin/myoglobin between groups ( p > 0.05). However, the oxygenated hemoglobin/myoglobin in T2DM was significantly higher than that in CON at an intensity above ventilatory threshold during the incremental cycling exercise ( p< 0.05).

This study suggests that patients with T2DM had early limitation of oxygen extraction and lower capacity of oxygenated myoglobin dissociation in the VL muscle. The fact that patients with T2DM showed different oxygen kinetics in a peripheral tissue from healthy subjects may partly explain the potential mechanisms of exercise intolerance in T2DM.