Fatty acid kinetic responses to exercise: Effects of obesity, body fat distribution, and energy-restricted diet

Jill A. Kanaley, Philip E. Cryer, Michael D. Jensen

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Upper body obesity (UB Ob) is associated with a reduced net free fatty acid (FFA) response to epinephrine compared with nonobese (Non Ob) and lower-body obese (LB Ob) women. Because catecholamines regulate some of the metabolic responses to exercise, we hypothesized that UB Ob would have a reduced net FFA response to exercise. Plasma FFA rate of appearance (Ra) ([1-14C]palnutate) and fatty acid oxidation (indirect calorimetry) were therefore measured during 2.5 h of stationary bicycle exercise (45% V̇O2 peak) in 13 UB Ob, 11 LB Ob, and 8 Non Ob premenopausal women. 10 UB Ob and 8 LB Ob women were retested after an ∼ 8-kg weight loss. Results: During exercise Non Ob and LB Ob women had greater increments in FFA availability (51±7 and 53±8 mmol, respectively) than UB Ob women (27±4 mmol, P < 0.05). Total exercise FFA availability and fatty acid oxidation were not different between Non Ob, LB Ob, and UB Ob women, however. Following weight loss (∼ 8 kg), the FFA response to exercise increased (P < 0.01) and remained greater (P < 0.05) in LB Ob than in UB Ob women. In conclusion, the FFA response to exercise was reduced in UB Ob women before and after weight loss, but no effects on fatty acid oxidation were apparent.

Original languageEnglish (US)
Pages (from-to)255-261
Number of pages7
JournalJournal of Clinical Investigation
Issue number1
StatePublished - Jul 1993



  • Body composition
  • Free fatty acids
  • Indirect calorimetry
  • Obesity
  • Weight loss

ASJC Scopus subject areas

  • Medicine(all)

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