title: Enhanced plasma IL-6 and IL-1ra responses to repeated vs. single bouts of prolonged cycling in elite athletes.
abstract: The impact of repeated bouts of exercise on plasma levels of interleukin (IL)-6 and IL-1 receptor antagonist (IL-1ra) was examined. Nine well-trained men participated in four different 24-h trials: Long [two bouts of exercise, at 0800-0915 and afternoon exercise (Ex-A), separated by 6 h]; Short (two bouts, at 1100-1215 and Ex-A, separated by 3 h); One (single bout performed at the same Ex-A as second bout in prior trials); and Rest (no exercise). All exercise bouts were performed on a cycle ergometer at 75% of maximal O(2) uptake and lasted 75 min. Peak IL-6 observed at the end of Ex-A was significantly higher in Short (8.8 +/- 1.3 pg/ml) than One (5.2 +/- 0.7 pg/ml) but not compared with Long (5.9 +/- 1.2 pg/ml). Peak IL-1ra observed 1 h postexercise was significantly higher in Short (1,774 +/- 373 pg/ml) than One (302 +/- 53 pg/ml) but not compared with Long (1,276 +/- 451 pg/ml). We conclude that, when a second bout of endurance exercise is performed after only 3 h of recovery, IL-6 and IL-1ra responses are elevated. This may be linked to muscle glycogen depletion.
authors.affiliation: Norwegian Olympic Sports Center, Norway. ola.ronsen@olympiatoppen.no
authors.forename: Ola
authors.initials: O
authors.lastname: Ronsen
authors.forename: Tor
authors.initials: T
authors.lastname: Lea
authors.forename: Roald
authors.initials: R
authors.lastname: Bahr
authors.forename: Bente Klarlund
authors.initials: BK
authors.lastname: Pedersen
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001786:Blood Glucose / Q000032:analysis; D004837:Epinephrine / Q000097:blood; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D011659:Pulmonary Gas Exchange; D012795:Sialoglycoproteins / Q000097:blood*
chemical_list: D001786:Blood Glucose; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D015850:Interleukin-6; D012795:Sialoglycoproteins; D004837:Epinephrine