Abstract Title:

Increased plasma FFA uptake and oxidation during prolonged exercise in trained vs. untrained humans.

Abstract Source:

Am J Physiol. 1992 Jun ;262(6 Pt 1):E791-9. PMID: 1319676

Abstract Author(s):

L P Turcotte, E A Richter, B Kiens

Article Affiliation:

August Krogh Institute, University of Copenhagen, Denmark.


We studied the effect of local muscle adaptations on free fatty acid (FFA) metabolism during prolonged exercise in trained and untrained subjects. Six trained (T) and six untrained (UT) young human males exercised for 3 h at 60% of their individual maximal dynamic knee extension capacity. The contribution of blood and plasma metabolites as well as intramuscular substrates to oxidative metabolism in the thigh was calculated from arteriovenous differences and femoral-venous blood flow as well as from muscle biopsies in subjects that were continuously infused with [1-14C]palmitate. Arterial plasma FFA concentration increased over time in both T and UT. Fractional uptake of FFA across the thigh remained unchanged over time in T (15%) but decreased in UT (from 15 to 7%), especially during the last hour of exercise. Thus FFA uptake increased linearly over time in T (96 +/- 20 to 213 +/- 20 mumol.min-1.kg-1), whereas it leveled off after 2 h in UT (74 +/- 16 to 133 +/- 46) even though FFA delivery increased similarly in T and UT. Percentage oxidation was similar in T and UT; thus total FFA oxidation was higher in T. Glucose uptake increased in both groups over time and was significantly higher in UT during the last hour of exercise. In conclusion, during prolonged knee extension exercise, FFA uptake increases linearly with FFA delivery in the trained thigh, whereas in the untrained thigh uptake becomes saturated with time. This difference partly explains the increased lipid oxidation in T vs. UT and suggests, furthermore, that local muscle adaptations to training are important for the utilization of FFA during prolonged exercise.

Study Type : Human Study
Additional Links
Pharmacological Actions : Fatty Acid Oxidation : CK(10) : AC(1)

Print Options

Key Research Topics

Sayer Ji
Founder of GreenMedInfo.com

Subscribe to our informative Newsletter & get Nature's Evidence-Based Pharmacy

Our newsletter serves 500,000 with essential news, research & healthy tips, daily.

Download Now

500+ pages of Natural Medicine Alternatives and Information.

This website is for information purposes only. By providing the information contained herein we are not diagnosing, treating, curing, mitigating, or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed healthcare professional.

© Copyright 2008-2022 GreenMedInfo.com, Journal Articles copyright of original owners, MeSH copyright NLM.