Effects of epinephrine and lactate on the increase in oxygen consumption of nonexercising skeletal muscle after aerobic exercise

Abstract

The purpose of this study was to measure O 2 consumption of nonexercising skeletal muscles (VO 2nonex ) at rest and after aerobic exercise and to investigate the stimulant factors of O 2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31 P-magnetic resonance spectroscopy during a 15 min arterial occlusion. In experiment 2, the VO 2nonex of the finger flexor muscles was measured using near infrared continuous wave spectroscopy at rest, immediate postexercise, and 3, 5, 10, 15, and 20 min following a cycling exercise at a workload load corresponding to 50% of peak pulmonary O 2 uptake for 20 min. We also monitored deep tissue temperature in the VO 2nonex measurement area and determined catecholamines and lactate concentrations in the blood at rest and immediate postexercise. VO 2nonex at rest was 1.1 ± 0.1 μM O 2 /s (mean±standard error) and VO 2nonex after exercise increased 59.6±7.2% (p < 0.001) from the resting values. There were significant correlations between the increase in VO 2nonex and the increase in epinephrine concentration (p < 0.01), and between the increase in VO 2nonex and the increase in lactate concentration (p < 0.05). These results suggest that epinephrine and lactate concentrations are important VO 2nonex stimulant factors.