Postexercise responses of muscle sympathetic nerve activity and blood flow to hyperinsulinemia in humans

• Published in: Journal of applied physiology (1985) 1999-08, Vol.87 (2), p.824-829
• Main Authors: Forjaz, Claudia L. M, Ramires, Paulo R, Tinucci, Tais, Ortega, Katia C, Salomao, Heloisa E. H, Ignes, Edna C, Wajchenberg, Bernardo L, Negrao, Carlos E, Mion, Decio, Jr
• Format: Article
• Language: English
• Subjects: Adult; Anatomy & physiology; Biological and medical sciences; Blood Glucose - metabolism; Blood Pressure; Diabetes. Impaired glucose tolerance; Electromyography; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Exercise; Exercise - physiology; Glucose Clamp Technique; Humans; Hyperinsulinism - blood; Hyperinsulinism - physiopathology; Insulin; Insulin - pharmacology; Male; Medical sciences; Muscles - blood supply; Muscles - innervation; Nervous system; Plethysmography; Regional Blood Flow; Space life sciences; Sympathetic Nervous System - metabolism
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1999.87.2.824

1  Laboratory of Exercise Physiology, School of Physical Education and Sports, 2  Hypertension Unit, Nefrology Division, 3  Endocrine Service, and 4  Laboratory of Cardiovascular Exercise Physiology, Heart Institute, Medical School, University of São Paulo, São Paulo, 05508-900 Brazil Although insulin and exercise cause dramatic changes in physiological parameters, the impact of exercise on neural and hemodynamic responses to insulin administration has not been described. In a study of the effects of a single bout of exercise on blood pressure (BP), muscle sympathetic nerve activity (MSNA), and forearm blood flow (FBF) responses to insulin infusion during the postexercise period, 11 healthy men underwent, in a random order, two hyperinsulinemic euglycemic clamps performed after 45 min of 1 ) bicycle exercise (50% peak O 2 uptake, Exercise session) and 2 ) seated rest (Control session). Data were analyzed during baseline and steady-state periods. Although insulin levels and insulin sensitivity were similar, baseline plasma glucose levels were significantly lower in the Exercise than in the Control session. Mean BP was significantly lower (3%) and FBF was higher (27%) in the Exercise session. Exercise increased insulin-induced MSNA enhancement (84%) without changing FBF and BP responses to hyperinsulinemia. In conclusion, a single bout of exercise that does not alter insulin sensitivity exacerbates insulin-induced increase in MSNA without changing FBF and BP responses to hyperinsulinemia. exercise; insulin sensitivity; blood pressure