Plasma free fatty acid concentration is closely tied to whole-body peak fat oxidation rate during repeated exercise
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Plasma free fatty acid concentration is closely tied to whole-body peak fat oxidation rate during repeated exercise. / Frandsen, Jacob; Vest, Stine Dahl; Ritz, Christian; Larsen, Steen; Dela, Flemming; Helge, Jørn Wulff.
I: Journal of Applied Physiology, Bind 126, Nr. 6, 2019, s. 1563-1571.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Plasma free fatty acid concentration is closely tied to whole-body peak fat oxidation rate during repeated exercise
AU - Frandsen, Jacob
AU - Vest, Stine Dahl
AU - Ritz, Christian
AU - Larsen, Steen
AU - Dela, Flemming
AU - Helge, Jørn Wulff
N1 - CURIS 2019 NEXS 191
PY - 2019
Y1 - 2019
N2 - Plasma free fatty acids (FFA) are a major contributor to whole body fat oxidation during exercise. However, to what extent, 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 peak fat oxidation rate in a dose dependent manner. 10 healthy young (31±6 years) (mean ± SD) well-trained (V̇O2max: 65.9±6.1 ml/min/kg) men performed 4 graded exercise tests (GXT) on one day. The GXT were interspersed by 4 hours of bedrest. This was conducted either in fasted state, or with the consumption of a standardized carbohydrate-rich meal 31/2 hours before each GXT. Fasting and previous GXT resulted in a gradual increase in PFO from 0.63±0.18g/min after an overnight fast (10 hours) to 0.93±0.17 g/min after app. 22 hours of fasting and three previous GTX. This increase in PFO coincided with an increase in plasma FFA concentrations (r2=0.73, p<0.0001). Ingestion of a carbohydrate-rich meal 31/2 hour before each GXT resulted in unaltered PFO rates. 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 peak fat oxidation rate and that the length of fasting and previous exercise are strong stimuli towards increasing plasma FFA concentration, highlighting the importance for pre-exercise standardisation when conducting graded exercise tests measuring substrate oxidation.
AB - Plasma free fatty acids (FFA) are a major contributor to whole body fat oxidation during exercise. However, to what extent, 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 peak fat oxidation rate in a dose dependent manner. 10 healthy young (31±6 years) (mean ± SD) well-trained (V̇O2max: 65.9±6.1 ml/min/kg) men performed 4 graded exercise tests (GXT) on one day. The GXT were interspersed by 4 hours of bedrest. This was conducted either in fasted state, or with the consumption of a standardized carbohydrate-rich meal 31/2 hours before each GXT. Fasting and previous GXT resulted in a gradual increase in PFO from 0.63±0.18g/min after an overnight fast (10 hours) to 0.93±0.17 g/min after app. 22 hours of fasting and three previous GTX. This increase in PFO coincided with an increase in plasma FFA concentrations (r2=0.73, p<0.0001). Ingestion of a carbohydrate-rich meal 31/2 hour before each GXT resulted in unaltered PFO rates. 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 peak fat oxidation rate and that the length of fasting and previous exercise are strong stimuli towards increasing plasma FFA concentration, highlighting the importance for pre-exercise standardisation when conducting graded exercise tests measuring substrate oxidation.
KW - Faculty of Science
KW - Fat oxidation rate
KW - Fasting
KW - Substrate availability
KW - Fatmax
U2 - 10.1152/japplphysiol.00995.2018
DO - 10.1152/japplphysiol.00995.2018
M3 - Journal article
C2 - 30844337
VL - 126
SP - 1563
EP - 1571
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 6
ER -
ID: 214683148