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Palmitate oxidation during rest, exercise, and post‐exercise recovery
Author(s) -
Henderson Gregory C.,
Fattor Jill A.,
Horning Michael A.,
Faghihnia Nastaran,
Mau Tamara L.,
LukeZeitoun Mona,
Brooks George A.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1450
Subject(s) - bicarbonate , medicine , zoology , chemistry , endocrinology , moderate exercise , physical exercise , excretion , exercise intensity , aerobic exercise , exercise physiology , heart rate , blood pressure , biology
We sought to explore the effects of exercise duration and intensity on post‐exercise lipid oxidation and used 13 C‐bicarbonate and ‐palmitate to determine the percentage of plasma free fatty acid (FFA) disposal that is oxidized (%Rdox) following exercise. Ten men received a continuous infusion of [1‐ 13 C]palmitate under 3 different conditions: (1) before, during and 3 hr after 90 min of exercise at 45% VO 2 peak (Mod), (2) before, during and 3 hr after 60 min of exercise at 65% VO 2 peak (Hard), and (3) during a time‐matched resting control trial (Con) with breath samples collected for determination of 13 CO 2 excretion rates. Diet was controlled and exercise trials were isoenergetic. Trials were repeated with a primed continuous infusion of [ 13 C]bicarbonate to derive correction factors for 13 CO 2 retention (k). Throughout Con, k was stable and averaged 0.83. During exercise, average k was 0.93 in Mod and 0.94 in Hard. After exercise, k returned rapidly to Con values in Mod but was less than Con at 30 and 60 min following Hard exercise (0.74 and 0.72, respectively, P < 0.05). FFA %Rdox increased over the 6 hr period in Con from 9 +/− 0.4% to 31 +− 1% (P < 0.05). During exercise, FFA %Rdox was greater in Hard than Mod with both elevated above Con (84 +− 2% and 109 +− 3% in Mod and Hard, respectively, P < 0.05). After exercise, %Rdox remained elevated above Con (P < 0.05) for 60 min in Hard and 30 min in Mod, but both subsequently returned to Con values. We conclude that FFA %Rdox is increased following prolonged exercise, reflecting a change in the relative partitioning of FFA between storage and oxidation. Supported by NIH grant AR42906 to GAB.