title: Cytokine response to eccentric exercise in young and elderly humans.
abstract: To examine the plasma interleukin (IL)-6 response in elderly (E) and young (Y) humans, 10 E and 10 Y subjects completed 60 min of eccentric lower limb exercise at the same relative oxygen uptake. Plasma IL-6 was measured before, immediately after, and 5 days into recovery from exercise, as were the biochemical markers of muscle damage, creatine kinase (CK), and myoglobin. In both groups, IL-6 increased (P < 0.05) immediately after exercise and peaked 4 h after exercise at 4.35 +/- 1.7 vs. 5.05 +/- 3.17 pg/ml for E and Y subjects, respectively. However, the increase in IL-6 in both groups was modest relative to the increases in CK peaking at 539 +/- 413 vs. 10,301 +/- 5,863 U/l for E and Y subjects, respectively. In addition, the increase in IL-6 was less pronounced (P < 0.05) in E subjects compared with Y subjects. These results suggest that IL-6 increases progressively after eccentric exercise, suggesting that this increase is related to muscle damage. However, the modest increase in IL-6, despite large increases in CK, suggests that the IL-6 response to muscle damage does not make an important contribution to the large increase in IL-6 observed during concentric exercise of long duration. Our data also suggest that aging may be associated with impaired repair mechanisms for exercise-induced muscle damage.
authors.affiliation: Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Anders Dyhr
authors.initials: AD
authors.lastname: Toft
authors.forename: Lars Bjørn
authors.initials: LB
authors.lastname: Jensen
authors.forename: Helle
authors.initials: H
authors.lastname: Bruunsgaard
authors.forename: Tobias
authors.initials: T
authors.lastname: Ibfelt
authors.forename: Jens
authors.initials: J
authors.lastname: Halkjaer-Kristensen
authors.forename: Mark
authors.initials: M
authors.lastname: Febbraio
authors.forename: Bente Klarlund
authors.initials: BK
authors.lastname: Pedersen
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood*; D001642:Bicycling; D015415:Biomarkers; D003402:Creatine Kinase / Q000097:blood; D016207:Cytokines / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D007958:Leukocyte Count; D018655:Lymphocyte Count; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D009211:Myoglobin / Q000097:blood; D009504:Neutrophils / Q000166:cytology; D009929:Organ Size; D005082:Physical Exertion / Q000502:physiology; D016526:Workload
chemical_list: D015415:Biomarkers; D016207:Cytokines; D015850:Interleukin-6; D009211:Myoglobin; D003402:Creatine Kinase