Differences in oxidative metabolism modulation induced by ischemia/reperfusion between trained and untrained individuals assessed by NIRS

Endurance training is associated with skeletal muscle adaptations that regulate the oxidative metabolism during ischemia/reperfusion. The aim of this study was to noninvasively assess in vivo differences in the oxidative metabolism activity during ischemia/reperfusion between trained and untrained individuals, using near infrared spectroscopy ( NIRS ) combined with a vascular occlusion test ( VOT ) technique ( NIRS ‐ VOT ). Sixteen untrained (26.3 ± 5.1 year) and seventeen trained (29.4 ± 4.9 year) healthy young adult men were submitted to a VOT (2 min baseline, 5 min occlusion, and 8 min reperfusion). Oxygen utilization was estimated from the area under the curve of the NIRS ‐derived deoxyhemoglobin [ HH b] signal during occlusion ( AUC occ). Muscle reperfusion was derived from the area above the curve ( AAC rep) of the [ HH b] signal after cuff release. The AUCocc of the untrained participants (21010 ± 9553 % · s) was significantly larger than the AUCocc of their trained counterparts (12320 ± 3283 % · s); P  = 0.001). The AACrep of the untrained participants (5928 ± 3769 % · s) was significantly larger than the AACrep of the trained participants (3745 ± 1900 % · s; P  = 0.042). There was a significant correlation between AUCocc and AACrep ( r  = 0.840; P  = 0.001). NIRS assessment of oxidative metabolism showed that trained individuals are more efficient in shifting between oxidative and anaerobic metabolism in response to ischemia and reperfusion.