scholarly journals Peak Fat Oxidation Rate Is Closely Associated With Plasma Free Fatty Acid Concentrations in Women; Similar to Men

2021 ◽  
Vol 12 ◽  
Author(s):  
Jacob Frandsen ◽  
Axel Illeris Poggi ◽  
Christian Ritz ◽  
Steen Larsen ◽  
Flemming Dela ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Whole Body ◽  
Men And Women ◽  
Fed State ◽  
Repeated Exercise ◽  
Graded Exercise ◽  
Plasma Ffa

Introduction: In men, whole body peak fat oxidation (PFO) determined by a graded exercise test is closely tied to plasma free fatty acid (FFA) availability. Men and women exhibit divergent metabolic responses to fasting and exercise, and it remains unknown how the combined fasting and exercise affect substrate utilization in women. We aimed to investigate this, hypothesizing that increased plasma FFA concentrations in women caused by fasting and repeated exercise will increase PFO during exercise. Then, that PFO would be higher in women compared with men (data from a previous study).Methods: On two separate days, 11 young endurance-trained women were investigated, either after an overnight fast (Fast) or 3.5 h after a standardized meal (Fed). On each day, a validated graded exercise protocol (GXT), used to establish PFO by indirect calorimetry, was performed four times separated by 3.5 h of bed rest both in the fasted (Fast) or fed (Fed) state.Results: Peak fat oxidation increased in the fasted state from 11 ± 3 (after an overnight fast, Fast 1) to 16 ± 3 (mean ± SD) mg/min/kg lean body mass (LBM) (after ~22 h fast, Fast 4), and this was highly associated with plasma FFA concentrations, which increased from 404 ± 203 (Fast 1) to 865 ± 210 μmol/L (Fast 4). No increase in PFO was found during the fed condition with repeated exercise. Compared with trained men from a former identical study, we found no sex differences in relative PFO (mg/min/kg LBM) between men and women, in spite of significant differences in plasma FFA concentrations during exercise after fasting.Conclusion: Peak fat oxidation increased with fasting and repeated exercise in trained women, but the relative PFO was similar in young trained men and women, despite major differences in plasma lipid concentrations during graded exercise.

scholarly journals Plasma free fatty acid concentration is closely tied to whole body peak fat oxidation rate during repeated exercise

2019 ◽  
Vol 126 (6) ◽  
pp. 1563-1571 ◽  
Author(s):  
Jacob Frandsen ◽  
Stine Dahl Vest ◽  
Christian Ritz ◽  
Steen Larsen ◽  
Flemming Dela ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Body Fat ◽  
Oxidation Rate ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Whole Body ◽  
Exercise Tests ◽  
Repeated Exercise ◽  
Plasma Ffa

Plasma free fatty acids (FFA) are a major contributor to whole body fat oxidation during exercise. However, the extent to which manipulating plasma FFA concentrations will influence whole body peak fat oxidation rate (PFO) during exercise remains elusive. In this study we aimed to increase plasma FFA concentrations through a combination of fasting and repeated exercise bouts. We hypothesized that an increase in plasma FFA concentration would increase PFO in a dose-dependent manner. Ten healthy young (31 ± 6 yr) (mean ± SD) well-trained (maximal oxygen uptake 65.9 ± 6.1 ml·min−1·kg−1) men performed four graded exercise tests (GXTs) on 1 day. The GXTs were interspersed by 4 h of bed rest. This was conducted either in a fasted state or with the consumption of a standardized carbohydrate-rich meal 3.5 h before each GXT. Fasting and previous GXTs resulted in a gradual increase in PFO from 0.63 ± 0.18 g/min after an overnight fast (10 h) to 0.93 ± 0.17 g/min after ∼22 h of fasting and three previous GXTs. This increase in PFO coincided with an increase in plasma FFA concentrations ( r2 = 0.73, P < 0.0001). Ingestion of a carbohydrate-rich meal 3.5 h before each GXT resulted in unaltered PFO. This was also reflected in unchanged plasma FFA, glucose, and insulin concentrations. In this study we show that plasma FFA availability is closely tied to whole body PFO and that the length of fasting combined with previous exercise are robust stimuli toward increasing plasma FFA concentration, highlighting the importance for preexercise standardization when conducting GXTs measuring substrate oxidation. NEW & NOTEWORTHY We show that peak fat oxidation is increased in close relationship with plasma free fatty acid availability after combined fasting and repeated incremental exercise tests in healthy highly trained men. Therefore it may be argued that whole body fat oxidation rate measured in most cases after an overnight fast indeed does not represent whole body maximal fat oxidation rate but a whole body peak fat oxidation rate within the context of the preexercise standardization obtained in the study design.

Dose-dependent effect of insulin on plasma free fatty acid turnover and oxidation in humans

1990 ◽  
Vol 259 (5) ◽  
pp. E736-E750 ◽  
Author(s):  
R. C. Bonadonna ◽  
L. C. Groop ◽  
K. Zych ◽  
M. Shank ◽  
R. A. DeFronzo
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Lipid Oxidation ◽  
Plasma Insulin ◽  
Plasma Free Fatty Acid ◽  
Whole Body ◽  
Glucose Disposal ◽  
Body Lipid ◽  
Plasma Ffa ◽  
Dose Dependent

Methodology for measuring plasma free fatty acid (FFA) turnover/oxidation with [1–14C]palmitate was tested in normal subjects. In study 1, two different approaches (720-min tracer infusion without prime vs. 150-min infusion with NaH14CO3 prime) to achieve steady-state conditions of 14CO2 yielded equivalent rates of plasma FFA turnover/oxidation. In study 2, during staircase NaH14CO3 infusion, calculated rates of 14CO2 appearance agreed closely with NaH14CO3 infusion rates. In study 3, 300-min euglycemic insulin clamp documented that full biological effect of insulin on plasma FFA turnover/oxidation was established within 60–120 min. In study 4, plasma insulin concentration was raised to 14 +/- 2, 23 +/- 2, 38 +/- 2, 72 +/- 5, and 215 +/- 10 microU/ml. A dose-dependent insulin suppression of plasma FFA turnover/oxidation was observed. Plasma FFA concentration correlated positively with plasma FFA turnover/oxidation in basal and insulinized states. Total lipid oxidation (indirect calorimetry) was significantly higher than plasma FFA oxidation in the basal state, suggesting that intracellular lipid stores contributed to whole body lipid oxidation. Hepatic glucose production and total glucose disposal showed the expected dose-dependent suppression and stimulation, respectively, by insulin. In conclusion, insulin regulation of plasma FFA turnover/oxidation is maximally manifest at low physiological plasma insulin concentrations, and in the basal state a significant contribution to whole body lipid oxidation originates from lipid pool(s) that are different from plasma FFA.

Reduced plasma FFA availability increases net triacylglycerol degradation, but not GPAT or HSL activity, in human skeletal muscle

2004 ◽  
Vol 287 (1) ◽  
pp. E120-E127 ◽  
Author(s):  
Matthew J. Watt ◽  
Anna G. Holmes ◽  
Gregory R. Steinberg ◽  
Jose L. Mesa ◽  
Bruce E. Kemp ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Body Fat ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Dry Mass ◽  
Hormone Sensitive Lipase ◽  
Whole Body ◽  
Plasma Ffa

Intramuscular triacylglycerols (IMTG) are proposed to be an important metabolic substrate for contracting muscle, although this remains controversial. To test the hypothesis that reduced plasma free fatty acid (FFA) availability would increase IMTG degradation during exercise, seven active men cycled for 180 min at 60% peak pulmonary O2 uptake either without (CON) or with (NA) prior ingestion of nicotinic acid to suppress adipose tissue lipolysis. Skeletal muscle and adipose tissue biopsy samples were obtained before and at 90 and 180 min of exercise. NA ingestion decreased ( P < 0.05) plasma FFA at rest and completely suppressed the exercise-induced increase in plasma FFA (180 min: CON, 1.42 ± 0.07; NA, 0.10 ± 0.01 mM). The decreased plasma FFA during NA was associated with decreased ( P < 0.05) adipose tissue hormone-sensitive lipase (HSL) activity (CON: 13.9 ± 2.5, NA: 9.1 ± 3.0 nmol·min−1·mg protein−1). NA ingestion resulted in decreased whole body fat oxidation and increased carbohydrate oxidation. Despite the decreased whole body fat oxidation, net IMTG degradation was greater in NA compared with CON (net change: CON, 2.3 ± 0.8; NA, 6.3 ± 1.2 mmol/kg dry mass). The increased IMTG degradation did not appear to be due to reduced fatty acid esterification, because glycerol 3-phosphate activity was not different between trials and was unaffected by exercise (rest: 0.21 ± 0.07; 180 min: 0.17 ± 0.04 nmol·min−1·mg protein−1). HSL activity was not increased from resting rates during exercise in either trial despite elevated plasma epinephrine, decreased plasma insulin, and increased ERK1/2 phosphorylation. AMP-activated protein kinase (AMPK)α1 activity was not affected by exercise or NA, whereas AMPKα2 activity was increased ( P < 0.05) from rest during exercise in NA and was greater ( P < 0.05) than in CON at 180 min. These data suggest that plasma FFA availability is an important mediator of net IMTG degradation, and in the absence of plasma FFA, IMTG degradation cannot maintain total fat oxidation. These changes in IMTG degradation appear to disassociate, however, from the activity of the key enzymes responsible for synthesis and degradation of this substrate.

Endurance training increases fatty acid turnover, but not fat oxidation, in young men

1999 ◽  
Vol 86 (6) ◽  
pp. 2097-2105 ◽  
Author(s):  
Anne L. Friedlander ◽  
Gretchen A. Casazza ◽  
Michael A. Horning ◽  
Anton Usaj ◽  
George A. Brooks
Keyword(s):  
Fatty Acid ◽  
Endurance Training ◽  
Exercise Intensity ◽  
Young Men ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Plasma Ffa ◽  
Total Fat

We examined the effects of exercise intensity and a 10-wk cycle ergometer training program [5 days/wk, 1 h, 75% peak oxygen consumption (V˙o 2 peak)] on plasma free fatty acid (FFA) flux, total fat oxidation, and whole body lipolysis in healthy male subjects ( n= 10; age = 25.6 ± 1.0 yr). Two pretraining trials (45 and 65% ofV˙o 2 peak) and two posttraining trials (same absolute workload, 65% of oldV˙o 2 peak; and same relative workload, 65% of newV˙o 2 peak) were performed by using an infusion of [1-13C]palmitate and [1,1,2,3,3-2H]glycerol. An additional nine subjects (age 25.4 ± 0.8 yr) were treated similarly but were infused with [1,1,2,3,3-2H]glycerol and not [1-13C]palmitate. Subjects were studied postabsorptive for 90 min of rest and 1 h of cycling exercise. After training, subjects increasedV˙o 2 peak 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 at 65%V˙o 2 peak(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.

Effect of exercise on FFA metabolism of pancreatectomized dogs

1963 ◽  
Vol 205 (4) ◽  
pp. 645-650 ◽  
Author(s):  
B. Issekutz ◽  
H. I. Miller ◽  
K. Rodahl
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Specific Activity ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Striking Difference ◽  
Heavy Exercise ◽  
Plasma Ffa ◽  
Ffa Metabolism ◽  
Pancreatectomized Dogs

Normal and pancreatectomized dogs with indwelling arterial and venous catheters were exercised on the treadmill for 35 min. Palmitate-1-C14 was infused intravenously for 3 hr during the experiment, or administered orally 15 hr before the experiment. The plasma free fatty acid (FFA) level was decreased in normal dogs but increased in the pancreatectomized animals during exercise. This was due to corresponding changes in the rate of FFA release. The rate of uptake of plasma FFA followed the rate of release with some delay, so that at the end of exercise the uptake was tenfold higher in the pancreatectomized dogs than in the controls. In spite of this striking difference, the C14O2 output was increased during exercise four- to fivefold in both groups in the infusion experiments. When the radiopalmitate was administered orally, however, the specific activity of the exhaled C14O2 rapidly decreased in the exercising pancreatectomized dogs but remained rather constant in the controls. It is suggested that during heavy exercise the muscles of the normal dog oxidize their endogenous fat pools, whereas the pancreatectomized animal relies for fat oxidation on the plasma FFA, the concentration of which is considerably increased by norepinephrine in the absence of insulin.

The Effects of Cold and Prostaglandin E1 on Lipid Mobilization in the Chicken

1971 ◽  
Vol 49 (5) ◽  
pp. 394-398 ◽  
Author(s):  
W. D. Wagner ◽  
R. A. Peterson ◽  
R. J. Cenedella
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Cold Exposure ◽  
Prostaglandin E1 ◽  
Plasma Free Fatty Acid ◽  
Prostaglandin E ◽  
Elevated Plasma ◽  
Lower Plasma ◽  
Lipid Mobilization ◽  
Plasma Ffa

Plasma free fatty acid (FFA) levels and the effects of prostaglandin E1 (PGE1) were studied in cold-acclimated and cold-exposed chickens and compared to controls. Chickens cold-acclimated at 4–7 or 8–11 °C for 4 weeks had significantly elevated plasma FFA when compared to the controls at 19–21 °C. Although PGE1 had no effect on the basal level of FFA of controls, a significantly lower plasma FFA was seen after injection of either 10 or 30 μg PGE1/kg in cold-acclimated chickens. Chickens cold-exposed to 2–3 °C for 4 h demonstrated significant elevations of plasma FFA when compared to controls. Only 30 μg PGE1/kg significantly depressed the plasma FFA in the cold-exposed birds. No inhibition of basal FFA release was seen in control animals. From these experiments, it is concluded that chickens mobilize FFA extensively under cold-exposure and that this stimulated lipolysis is inhibited by PGE1.

scholarly journals Effects of exercise before breakfast on plasma free fatty acid profile and 24-h fat oxidation

2020 ◽  
Vol 8 ◽  
pp. 100067
Author(s):  
Kaito Iwayama ◽  
Ayane Ogawa ◽  
Yoshiaki Tanaka ◽  
Katsuhiko Yajima ◽  
Insung Park ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Fatty Acid Profile ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation

Effect of endurance training on plasma free fatty acid turnover and oxidation during exercise

1993 ◽  
Vol 265 (5) ◽  
pp. E708-E714 ◽  
Author(s):  
W. H. Martin ◽  
G. P. Dalsky ◽  
B. F. Hurley ◽  
D. E. Matthews ◽  
D. M. Bier ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Exercise Training ◽  
Endurance Exercise ◽  
Prolonged Exercise ◽  
Plasma Free Fatty Acid ◽  
Cycle Ergometer ◽  
Endurance Exercise Training ◽  
Plasma Ffa ◽  
Total Fat

Plasma free fatty acid (FFA) levels tend to be lower and the plasma lipolytic hormone response to prolonged exercise of the same intensity is blunted after endurance exercise training. To determine whether training elicits a corresponding decrease in plasma FFA turnover and metabolism during prolonged exercise, we measured plasma [1-13C]palmitate kinetics and oxidation and respiratory gas exchange in 13 subjects during the latter portion of a 90- to 120-min bout of cycle ergometer work performed before and after 12 wk of alternate-day cycling and running. Training increased total fat oxidation during prolonged exercise by 41% (P < 0.005). However, for the final 30-60 min of the cycle ergometer protocol, the rate of 13CO2 production from [1-13C]palmitate oxidation was 27% lower (P < 0.05), the rate of palmitate turnover was 33% less (P < 0.05), and plasma FFA and glycerol concentrations were 32 and 20% lower (P < 0.05), respectively, than in the untrained state. Thus endurance exercise training results in decreased plasma FFA turnover and oxidation during a 90- to 120-min bout of submaximal exercise because of a slower rate of FFA release from adipose tissue.

High-fat diet elevates resting intramuscular triglyceride concentration and whole body lipolysis during exercise

2004 ◽  
Vol 286 (2) ◽  
pp. E217-E225 ◽  
Author(s):  
Theodore W. Zderic ◽  
Christopher J. Davidson ◽  
Simon Schenk ◽  
Lauri O. Byerley ◽  
Edward F. Coyle
Keyword(s):  
High Fat Diet ◽  
Control Diet ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Whole Body ◽  
High Fat ◽  
Appearance Rate ◽  
Plasma Ffa ◽  
Adipose Tissue Lipolysis ◽  
Intramuscular Triglyceride

This study determined the role of intramuscular triglyceride (IMTG) and adipose lipolysis in the elevated fat oxidation during exercise caused by a high-fat diet. In four separate trials, six endurance-trained cyclists exercised at 50% peak O2 consumption for 1 h after a two-day control diet (22% fat, CON) or an isocaloric high-fat diet (60% fat, HF) with or without the ingestion of acipimox, an adipose lipolysis inhibitor, before exercise. During exercise, HF elevated fat oxidation by 72% and whole body lipolysis [i.e., the appearance rate of glycerol in plasma (Ra glycerol)] by 79% compared with CON ( P < 0.05), and this was associated with a 36% increase ( P < 0.05) in preexercise IMTG concentration. Although acipimox lowered plasma free fatty acid (FFA) availability, HF still increased fat oxidation and Ra glycerol to the same magnitude above control as the increase caused by HF without acipimox (i.e., both increased fat oxidation 13–14 μmol·kg–1·min–1). In conclusion, the marked increase in fat oxidation after a HF diet is associated with elevated IMTG concentration and whole body lipolysis and does not require increased adipose tissue lipolysis and plasma FFA concentration during exercise. This suggests that altered substrate storage in skeletal muscle is responsible for increased fat oxidation during exercise after 2 days of an HF diet.

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