Author/Editor		Friedlander, Anne L; Casazza, Gretchen A; Horning, Michael A; Ušaj, Anton; Brooks, George A
Title		Endurance training increases fatty acid turnover, but not fat oxidation, in young men
Type		članek
Source		J Appl Physiol
Vol. and No.		Letnik 86, št. 6
Publication year		1999
Volume		str. 2097-105
Language		eng
Abstract		We examined the effects of exercise intensity and a 10-wk cycle ergometer training program (5 days/wk, 1 h, 75% peak oxygen consumption (VO2peak)) on plasma free fatty acid (FFA) flux, total fat oxidation, and a whole body lipolysis in healthy male subjects (n=10, age=25.6 +- 1.0 yr). Two pretraining trials (45 and 65% of VO2peak) and two posttraining trials (same absolute workload, 65% of old VO2peak; and same relative workload, 65% of new VO2peak were performed by uisng an in fusion of (1-13C) palmitate and (1,1,2,3,3- H2) glycerol. An additional nine subjects (age 25.4 +-0.8 yr) were treated similary but were infused with (1,1,2,3,3- H2) glycerol and not (1-13C) palmitate. Subjects were studied postabsorptive for 90 min of rest and 1h of cycling exercise. After training, subjects increased VO2peak by 9.4+-1.4%. Pretraining, plasma FFA kinetics were inversely related to exercise intensity with rates of appearance (Ra) and disappearance (Rd) being significantly higher at 45 than 65% VO2peak (RA:8.14 +- 1.28 vs. 6.64 +- 0.46, Rd 8.03 +- 1.28 vs 6.42 +- 0.41 mol kg-1 min-1)(P<=0.05). After training, when measured at the same absolute and relative intensities, FFA Ra increased to 8.84 +- 1.1, 8.44 +- 1.1 and Rd to 8.82 +- 1.1, 8.35 +- 1.1 mol kg-1 min -1, respectively (p<=0.05). Total fat oxidation determined from respiratory exchange ratio was elevated during exercise compared with rest, but did not differ among the four conditions. Glycerol Ra was elevated during exercise compared with rest but did not demonstrate significant intensity or training effects during exercise. Thus, in young men, plasma FFA flux is increased during exercise after endurance training, but total fat oxidation and whole-body lipolysis are unaffected when measured at the same absolute or relative exercise intensities.
Descriptors		DIETARY FATS FATTY ACIDS PHYSICAL ENDURANCE PHYSICAL FITNESS ADOLESCENCE ADULT BODY COMPOSITION EXERCISE FATTY ACIDS, NONESTERIFIED OXIDATION-REDUCTION REST