Muscle Exercise, Energy Metabolism and Blood Lactate

Author(s):  
Jan Karlsson
1962 ◽  
Vol 17 (2) ◽  
pp. 184-190 ◽  
Author(s):  
P. F. Scholander ◽  
H. T. Hammel ◽  
H. LeMessurier ◽  
E. Hemmingsen ◽  
W. Garey

A seemingly general feature in the adjustment to diving in various mammals, birds, and reptiles is a slow-down and redistribution of the circulation, leaving muscles, periphery, and certain visceral organs with a markedly reduced circulation. This saves oxygen and causes widespread reduction of the energy metabolism. Active as well as quiet diving develops bradycardia without drop in central blood pressure, and lactic acid forming in the muscles during the dive floods the blood when breathing starts. In 31 native skin divers in Australia, diving rarely exceeded 1 min. During the dive, blood pressure stayed normal while heart rate dropped to half; blood lactate (five divers) remained normal but showed an acute rise in the recovery. Evidently humans utilize an adjustment similar to animals. Most of our divers developed various cardiac arrhythmias during the dive, persisting sometimes into the beginning of the recovery. This asphyxial defense seems developed at birth, for fetal bradycardia is common during delivery, and an acute rise of lactic acid after delivery has recently been described. Phylogenetically the mechanism is ancient, for it is found also in fishes when taken out of water. Submitted on August 7, 1961


Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.


2012 ◽  
Vol 50 (01) ◽  
Author(s):  
S Lünse ◽  
A Krüger ◽  
M Glanemann ◽  
G Damm

2015 ◽  
Vol 53 (01) ◽  
Author(s):  
K Schönefeld ◽  
M Matz-Soja ◽  
J Böttger ◽  
P Seibel ◽  
R Gebhardt
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