title: Aerobic exercise, but not flexibility/resistance exercise, reduces serum IL-18, CRP, and IL-6 independent of beta-blockers, BMI, and psychosocial factors in older adults.
abstract: Increased serum levels of inflammatory mediators have been associated with numerous disease states including atherosclerosis, Type II diabetes, hypertension, depression, and overall mortality. We hypothesized that a long-term exercise intervention among older adults would reduce serum inflammatory cytokines, and this reduction would be mediated, in part, by improvements in psychosocial factors and/or by beta-adrenergic receptor mechanisms. Adults age 64 were randomly assigned to either an aerobic exercise treatment (CARDIO) or a flexibility/strength exercise treatment (FLEX) 3 days/week, 45 min/day for 10 months. A subgroup of subjects treated with non-selective beta(1)beta(2) adrenergic antagonists were included to evaluate the potential role of beta-adrenergic receptor adaptations as mediators of an exercise-induced change in inflammation. The inflammatory mediators [C-reactive protein (CRP), IL-6, tumor necrosis factor (TNF)-alpha, and IL-18] and the psychosocial factors (depression, perceived stress, optimism, sense of coherence, and social support) were measured pre- and post-intervention. The CARDIO treatment resulted in significant reductions in serum CRP, IL-6, and IL-18 compared to the FLEX treatment (significant treatment x time interaction, p<.05), whereas TNFalpha declined in both groups (main effect of time, p=.001). However, several psychosocial factors (depression, optimism, and sense of coherence) improved in both groups suggesting that the reduction of CRP, IL-6, and IL-18 in the CARDIO group was not mediated by improvements in psychosocial scores. With respect to the potential role of beta-adrenergic receptors, both CARDIO subjects treated with beta-adrenergic antagonists and those who were not treated with those medications demonstrated similar reductions in serum CRP, IL-6, IL-18, and TNFalpha. In summary, we have observed that an aerobic exercise intervention can significantly reduce serum inflammatory mediators, but beta-adrenergic receptors and psychosocial factors do not appear to be involved.
authors.affiliation: Department of Health and Human Performance, Immunobiology, Gerontology, Animal Science, Iowa State University, Ames, IA, USA. mkohut@iastate.edu
authors.forename: M L
authors.initials: ML
authors.lastname: Kohut
authors.forename: D A
authors.initials: DA
authors.lastname: McCann
authors.forename: D W
authors.initials: DW
authors.lastname: Russell
authors.forename: D N
authors.initials: DN
authors.lastname: Konopka
authors.forename: J E
authors.initials: JE
authors.lastname: Cunnick
authors.forename: W D
authors.initials: WD
authors.lastname: Franke
authors.forename: M C
authors.initials: MC
authors.lastname: Castillo
authors.forename: A E
authors.initials: AE
authors.lastname: Reighard
authors.forename: E
authors.initials: E
authors.lastname: Vanderah
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000368:Aged / Q000502:physiology* / Q000523:psychology; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D015444:Exercise / Q000502:physiology* / Q000523:psychology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000523:psychology; D018836:Inflammation Mediators / Q000097:blood*; D020382:Interleukin-18 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D005082:Physical Exertion / Q000502:physiology; D018583:Pliability; D011584:Psychology; D012016:Reference Values; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
chemical_list: D000319:Adrenergic beta-Antagonists; D018836:Inflammation Mediators; D020382:Interleukin-18; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein