title: Postexercise fat intake repletes intramyocellular lipids but no faster in trained than in sedentary subjects.
abstract: The hypotheses that postexercise replenishment of intramyocellular lipids (IMCL) is enhanced by endurance training and that it depends on fat intake were tested. Trained and untrained subjects exercised on a treadmill for 2 h at 50% peak oxygen consumption, reducing IMCL by 26-22%. During recovery, they were fed 55% (high fat) or 15% (low fat) lipid energy diets. Muscle substrate stores were estimated by (1)H (IMCL)- and (13)C (glycogen)-magnetic resonance spectroscopy in tibialis anterior muscle before and after exercise. Resting IMCL content was 71% higher in trained than untrained subjects and correlated significantly with glycogen content. Both correlated positively with indexes of insulin sensitivity. After 30 h on the high-fat diet, IMCL concentration was 30-45% higher than preexercise, whereas it remained 5-17% lower on the low-fat diet. Training status had no significant influence on IMCL replenishment. Glycogen was restored within a day with both diets. We conclude that fat intake postexercise strongly promotes IMCL repletion independently of training status. Furthermore, replenishment of IMCL can be completed within a day when fat intake is sufficient.
authors.affiliation: Nestlé Research Center, Nestec Ltd., PO Box 44, CH-1000 Lausanne 26, Switzerland. jacques.decombaz@rdls.nestle.com
authors.forename: J
authors.initials: J
authors.lastname: Décombaz
authors.forename: B
authors.initials: B
authors.lastname: Schmitt
authors.forename: M
authors.initials: M
authors.lastname: Ith
authors.forename: B
authors.initials: B
authors.lastname: Decarli
authors.forename: P
authors.initials: P
authors.lastname: Diem
authors.forename: R
authors.initials: R
authors.lastname: Kreis
authors.forename: H
authors.initials: H
authors.lastname: Hoppeler
authors.forename: C
authors.initials: C
authors.lastname: Boesch
mesh_terms: D000328:Adult; D001823:Body Composition / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002247:Carbon Isotopes; D004041:Dietary Fats / Q000378:metabolism*; D005080:Exercise Test; D006003:Glycogen / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D019344:Lactic Acid / Q000097:blood; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D004041:Dietary Fats; D008055:Lipids; D019344:Lactic Acid; D006003:Glycogen