Effects of short- and long-term detraining on the metabolic response to endurance exercise.
Changes in the metabolic response to an endurance exercise were studied (18 rowing km at 75 % of maximal aerobic velocity) during detraining in ten rowers previously highly-trained. Maximal aerobic velocity (VO2 max) and the metabolic response to exercise were determined in the 1 st, 24 th, and 47 th week (training), and in the 52 nd, 76 th, and 99 th week (detraining). Over the decrease of VO2 max, detraining induced a biphasic alteration of the previously observed training adaptations: 1-short-term detraining (5 weeks) resulted in a lower adipose tissue triglyceride (TG) delivery during exercise (p = 0.029), but this one did not represent a direct metabolic limit to exercise since the liver TG delivery increased (p = 0.039), allowing that total fatty acid concentration remained unchanged (12.1 +/- 2.4 vs. 11.8 +/- 2.1 mmol/l; weeks 47 vs. 52); 2-long-term detraining (52 weeks) altered even more the metabolic response to exercise with a decreased total fatty acid concentration during exercise (week 99: 10.6 +/- 2.0 mmol/l; p = 0.022), which induced a higher glycolysis utilization. At this moment, a hemolytic response to endurance exercise was observed through haptoglobin and transferrin concentration changes (weeks 47 vs. 99; p = 0.029 and 0.027, respectively), which resulted probably from higher red blood cell destruction. Endurance-trained athletes should avoid detraining periods over a few weeks since alterations of the metabolic adaptations to training may become rapidly chronic after such delays.
Petibois
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INSERM U443, Groupe de Chimie Bio-Organique, Université Victor Segalen Bordeaux 2, Bordeaux, France. cyril.petibois@bioorga.u-bordeaux2.fr
Déléris
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D000222:Adaptation, Physiological; D000328:Adult; D000596:Amino Acids / Q000097:blood; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism; D005227:Fatty Acids / Q000097:blood; D005990:Glycerol / Q000097:blood; D006801:Humans; D007773:Lactates / Q000097:blood; D016014:Linear Models; D008297:Male; D010806:Physical Education and Training; D010807:Physical Endurance / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D014280:Triglycerides / Q000097:blood
D000596:Amino Acids; D001786:Blood Glucose; D005227:Fatty Acids; D007773:Lactates; D011506:Proteins; D014280:Triglycerides; D005990:Glycerol