Fatty acid kinetic responses to exercise. Effects of obesity, body fat distribution, and energy-restricted diet.
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]palmitate) and fatty acid oxidation (indirect calorimetry) were therefore measured during 2.5 h of stationary bicycle exercise (45% VO2 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 approximately 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 (approximately 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.
Kanaley
J A
JA
Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905.
Cryer
P E
PE
Jensen
M D
MD
D001823:Body Composition; D050260:Carbohydrate Metabolism; D004038:Diet, Reducing; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007657:Ketone Bodies / Q000378:metabolism; D008053:Lipid Mobilization; D009765:Obesity / Q000378:metabolism*; D010101:Oxygen Consumption; D005082:Physical Exertion
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007657:Ketone Bodies