title: Influence of acute exercise with and without carbohydrate replacement on postprandial lipid metabolism.
abstract: Acute exercise, undertaken on the day before an oral fat tolerance test (OFTT), typically reduces postprandial triglycerides (TG) and increases high-density lipoprotein-cholesterol (HDL-C). However, the benefits of acute exercise may be overstated when studies do not account for compensatory changes in dietary intake. The objective of this study was to determine the influence of acute exercise, with and without carbohydrate (CHO) replacement, on postprandial lipid metabolism. Eight recreationally active young men underwent an OFTT on the morning after three experimental conditions: no exercise [control (Con)], prolonged exercise without CHO replacement (Ex-Def) and prolonged exercise with CHO replacement to restore CHO and energy balance (Ex-Bal). The exercise session in Ex-Def and Ex-Bal consisted of 90 min cycle ergometry at 70% peak oxygen uptake (Vo(2peak)) followed by 10 maximal 1-min sprints. CHO replacement was achieved using glucose solutions consumed at 0, 2, and 4 h postexercise. Muscle glycogen was 40 +/- 4% (P < 0.05) and 94 +/- 3% (P = 0.24) of Con values on the morning of the Ex-Def and Ex-Bal OFTT, respectively. Postprandial TG were 40 +/- 14% lower and postprandial HDL-C, free fatty acids, and 3-hydroxybutyrate were higher in Ex-Def compared with Con (P < 0.05). Most importantly, these exercise effects were not evident in Ex-Bal. Postprandial insulin and glucose and the homeostatic model assessment of insulin resistance (HOMA(IR)) were not significantly different across trials. There was no relation between the changes in postprandial TG and muscle glycogen across trials. In conclusion, the influence of acute exhaustive exercise on postprandial lipid metabolism is largely dependent on the associated CHO and energy deficit.
authors.affiliation: Department of Health, Sport and Exercise Science, Waterford Institute of Technology, Waterford, Ireland. mharrison@wit.ie
authors.forename: Michael
authors.initials: M
authors.lastname: Harrison
authors.forename: Donal J
authors.initials: DJ
authors.lastname: O'Gorman
authors.forename: Noel
authors.initials: N
authors.lastname: McCaffrey
authors.forename: Marc T
authors.initials: MT
authors.lastname: Hamilton
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Zderic
authors.forename: Brian P
authors.initials: BP
authors.lastname: Carson
authors.forename: Niall M
authors.initials: NM
authors.lastname: Moyna
mesh_terms: D000284:Administration, Oral; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005508:Food Deprivation / Q000502:physiology; D005951:Glucose Tolerance Test; D006003:Glycogen / Q000032:analysis; D006439:Hemodynamics; D006801:Humans; D015228:Hypertriglyceridemia / Q000097:blood*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry; D010101:Oxygen Consumption; D019518:Postprandial Period / Q000502:physiology*; D011659:Pulmonary Gas Exchange; D014280:Triglycerides / Q000097:blood
chemical_list: D004040:Dietary Carbohydrates; D007328:Insulin; D014280:Triglycerides; D006003:Glycogen