TY - JOUR
T1 - Fatty acid kinetic responses to running above or below lactate threshold
AU - Kanaley, J. A.
AU - Mottram, C. D.
AU - Scanlon, P. D.
AU - Jensen, M. D.
PY - 1995
Y1 - 1995
N2 - During running exercise above the lactate threshold (LT), it is unknown whether free fatty acid (FFA) mobilization can meet the energy demands for fatty acid oxidation. This study was performed to determine whether FFA availability is reduced during running exercise above compared with below the LT and to assess whether the level of endurance training influences FFA mobilization. Twelve marathon runners and 12 moderately trained runners ran at a workload that was either above or below their individual LT. Fatty acid oxidation (indirect calorimetry) and FFA release ([1-14C]palmitate) were measured at baseline, throughout exercise, and at recovery. The plasma FFA rate of appearance increased during exercise in both groups, running above or below the LT, but the total FFA availability for 30 min of exercise was greater (P < 0.01) in the below LT group (marathon, 23 ± 2 mmol; moderate, 21 ± 2 mmol) than in the above LT group (18 ± 3 and 13 ± 3 mmol, respectively). Total fatty acid oxidation (indirect calorimetry) greatly exceeded circulating FFA availability, regardless of training or exercise group (P < 0.01). No statistically significant exercise intensity or training differences in fatty acid oxidation were found (above LT: marathon, 71 ± 12, moderate, 64 ± 17 mmol/30 min; below LT: marathon 91 ± 12, moderate, 60 ± 5 mmol/30 rain). In conclusion, during exercise above or below LT, circulating FFA cannot meet the oxidative needs and intramuscular triglyceride stores must be utilized. Further marathon training does not enhance effective adipose tissue lipolysis during exercise compared with moderate endurance training.
AB - During running exercise above the lactate threshold (LT), it is unknown whether free fatty acid (FFA) mobilization can meet the energy demands for fatty acid oxidation. This study was performed to determine whether FFA availability is reduced during running exercise above compared with below the LT and to assess whether the level of endurance training influences FFA mobilization. Twelve marathon runners and 12 moderately trained runners ran at a workload that was either above or below their individual LT. Fatty acid oxidation (indirect calorimetry) and FFA release ([1-14C]palmitate) were measured at baseline, throughout exercise, and at recovery. The plasma FFA rate of appearance increased during exercise in both groups, running above or below the LT, but the total FFA availability for 30 min of exercise was greater (P < 0.01) in the below LT group (marathon, 23 ± 2 mmol; moderate, 21 ± 2 mmol) than in the above LT group (18 ± 3 and 13 ± 3 mmol, respectively). Total fatty acid oxidation (indirect calorimetry) greatly exceeded circulating FFA availability, regardless of training or exercise group (P < 0.01). No statistically significant exercise intensity or training differences in fatty acid oxidation were found (above LT: marathon, 71 ± 12, moderate, 64 ± 17 mmol/30 min; below LT: marathon 91 ± 12, moderate, 60 ± 5 mmol/30 rain). In conclusion, during exercise above or below LT, circulating FFA cannot meet the oxidative needs and intramuscular triglyceride stores must be utilized. Further marathon training does not enhance effective adipose tissue lipolysis during exercise compared with moderate endurance training.
KW - [1-C]palmitate
KW - free fatty acids
KW - indirect calorimetry
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U2 - 10.1152/jappl.1995.79.2.439
DO - 10.1152/jappl.1995.79.2.439
M3 - Article
C2 - 7592200
AN - SCOPUS:0029166115
SN - 8750-7587
VL - 79
SP - 439
EP - 447
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 2
ER -