Sympathetic denervation of the upper limb improves forearm exercise performance and skeletal muscle bioenergetics

Background-Sympathetic activation may limit exercise performance by restrai ning muscle blood flow or by negatively affecting skeletal muscle metabolic behavior. To test this hypothesis, we studied the effect of thoracoscopic sympathetic trunkotomy (TST) on forearm exercise duration, blood flow, and muscle bioenergetics in 13 patients with idiopathic palmar hyperhidrosis. Methods and Results-Heart rate and beat-by-beat mean arterial pressure were recorded at rest and during right and left rhythmic handgrip before and 4 to 7 weeks after right TST. Forearm blood flow was measured bilaterally at rest and on the right during exercise. Right forearm muscle phosphocreatine content and intracellular pH were assessed by (31)phosphorus magnetic reso nance spectroscopy. After right TST, exercise duration increased from 8.9+/ -1.4 to 13.4 +/- 1.8 minutes (P<0.0001) with the right forearm and from 5.7 +/-0.4 to 7.6+/-0.9 minutes (P<0.05) with the left (P<0.05 for the interact ion between treatment and side). Right forearm blood Row at rest was 66% hi gher (P<0.01) after right TST, but this difference decreased as the exercis e progressed. After right TST, a significant reduction occurred in muscle a cidification and phosphocreatine depletion during ipsilateral forearm exerc ise. This was associated with a significantly reduced mean arterial pressur e response to right handgrip, whereas the presser response to left handgrip did not change. Conclusions-Sympathetic denervation of the upper limb significantly improve s forearm skeletal muscle bioenergetics and exercise performance in patient s with idiopathic palmar hyperhidrosis.