TY - JOUR

T1 - Hormonal and metabolic responses to electrically induced cycling during epidural anesthesia in humans

AU - Kjær, Michael

AU - Secher, Niels H.

AU - Bangsbo, Jens

AU - Perko, G.

AU - Horn, A.

AU - Mohr, T.

AU - Galbo, Henrik

PY - 1996

Y1 - 1996

N2 - Hormonal and metabolic responses to electrically induced dynamic exercise were investigated in eight healthy young men with afferent neural influence from the legs blocked by epidural anesthesia (25 ml of 2% lidocaine) at L2-L4. This caused cutaneous sensory anesthesia below T8- T9 and complete paralysis of the legs. Cycling increased oxygen uptake to 1.90 ± 0.13 (SE) l/min, and fatigue developed after 22.7 ± 2.7 min. Compared with voluntary exercise at the same oxygen uptake and heart rate, concentrations of blood and muscle lactate (musculus vastus lateralis) as well as plasma potassium increased more while muscle glycogen decreased more during electrically induced exercise. Hepatic glucose production always rose during exercise. However, during involuntary exercise with sensory blockade, it did not match the rise in peripheral glucose uptake and plasma glucose decreased (P < 0.05). Plasma glycerol increased less in electrically induced vs. voluntary exercise, and free fatty acids and β-hydroxybutyrate decreased only during electrically induced exercise. Epinephrine, growth hormone, adrenocorticotropic hormone, and cortisol levels were higher during involuntary vs. voluntary exercise (P < 0.05). In conclusion, neural and humoral mechanisms exert redundant control with regard to responses of catecholamines and pituitary hormones (growth hormone and adrenocorticotropic hormone). In contrast, neural input from motor centers and feedback from working muscle are important for glucose production and lipolysis during exercise in humans. Humoral feedback is apparently not sufficient to trigger normal mobilization of extramuscular fuel stores.

AB - Hormonal and metabolic responses to electrically induced dynamic exercise were investigated in eight healthy young men with afferent neural influence from the legs blocked by epidural anesthesia (25 ml of 2% lidocaine) at L2-L4. This caused cutaneous sensory anesthesia below T8- T9 and complete paralysis of the legs. Cycling increased oxygen uptake to 1.90 ± 0.13 (SE) l/min, and fatigue developed after 22.7 ± 2.7 min. Compared with voluntary exercise at the same oxygen uptake and heart rate, concentrations of blood and muscle lactate (musculus vastus lateralis) as well as plasma potassium increased more while muscle glycogen decreased more during electrically induced exercise. Hepatic glucose production always rose during exercise. However, during involuntary exercise with sensory blockade, it did not match the rise in peripheral glucose uptake and plasma glucose decreased (P < 0.05). Plasma glycerol increased less in electrically induced vs. voluntary exercise, and free fatty acids and β-hydroxybutyrate decreased only during electrically induced exercise. Epinephrine, growth hormone, adrenocorticotropic hormone, and cortisol levels were higher during involuntary vs. voluntary exercise (P < 0.05). In conclusion, neural and humoral mechanisms exert redundant control with regard to responses of catecholamines and pituitary hormones (growth hormone and adrenocorticotropic hormone). In contrast, neural input from motor centers and feedback from working muscle are important for glucose production and lipolysis during exercise in humans. Humoral feedback is apparently not sufficient to trigger normal mobilization of extramuscular fuel stores.

KW - Adrenocorticotropic hormone

KW - Creatine phosphate

KW - Epinephrine

KW - Free fatty acids

KW - Growth hormone

KW - Hepatic glucose production

KW - Insulin

KW - Lactate

KW - Muscle glycogen

KW - Norepinephrine

KW - Renin

UR - http://www.scopus.com/inward/record.url?scp=0030035084&partnerID=8YFLogxK

U2 - 10.1152/jappl.1996.80.6.2156

DO - 10.1152/jappl.1996.80.6.2156

M3 - Journal article

C2 - 8806925

AN - SCOPUS:0030035084

VL - 80

SP - 2156

EP - 2162

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 6

ER -