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1992 Publications

Regulation of Substrate Mobilization - Electrical Induced Bicycling in Tetraplegicsby M. Kjaer, S.F. Pollack*, H. Weiss, G. W. Gleim, H. Galbo* and K.T. Ragnarsson*.Mt. Sinai School of Med., New York and Dept. of Int. Med. TTA, Univ. of Copenhagen, Denmark. - last modified 2013-02-09 00:00
Med. Sci. Sports Exerc., Vol. 24(5):s112, 1992.


The importance of blood born mechanisms on substrate mobilization was investigated in 6 spinal cord injured quadraplegic (C5-T1) males with loss of voluntary control of leg muscles. Subjects performed functional electrical stimulation (FES) of the legs to fatigue (<35 rpm) (24.6 +/- 23 min, mean and SE) on a bicycle ergometer.

Voluntary arm exercise was performed as control. During FES, an increase in heart rate from 66 +/- 4 to 98 +/- 5 bpm, a small increase in plasma norepinephrine (to: 1.5 +/- 0.3 nmol/l), but no increase in plasma epinephrine concentration was found. Plasma insulin did not decrease during exercise (p >0.05). Peripheral glucose uptake increased during FES to 21.5 +/- 4.3 (mol/min/kg, whereas hepatic glucose production did not change from basal values (14.4 +/- 1.4 umol/min/kg).

Due to this mismatch plasma glucose gradually decreased during FES (5.4 +/- 0.4 mmol/l(rest) to 4.7 +/- 0.3(stop) (p < 0.05), whereas plasma glucose was constant in response to voluntary arm cranking. In conclusion, when efferent and afferent pathways to CNS are absent due to spinal cord injury, blood born mechanisms are not sufficient for an adequate glucose mobilization during low-intensity exercise in man.