Inflammation and oxidative stress are lower in physically fit and active adults R. A. Shanely 1,2 , D. C. Nieman 1,2 , D. A. Henson 3 , F. Jin 1,2 , A. M. Knab 1,2 , W. Sha 4 1 Human Performance Laboratory, Appalachian State University, North Carolina Research Campus, Kannapolis, North Carolina, USA, 2 College of Health Sciences, Appalachian State University, Boone, North Carolina, USA, 3 Department of Biology, Appalachian State University, Boone, North Carolina, USA, 4 Bioinformatics Service Division, University of North Carolina at Charlotte, North Carolina Research Campus, Kannapolis, North Carolina, USA Corresponding author: R.Andrew Shanely, PhD, Human Performance Laboratory, North Carolina Research Campus, Plants for Human Health Institute, 600 Laureate Way, Kannapolis, North Carolina 28081, USA. Tel: 704.250.5357, Fax: 704.250.5428, E-mail: shanelyra@appstate.edu Accepted for publication 20 June 2011 The objective of this study was to determine if the inverse relationship between perceived physical fitness (pFIT) and exercise frequency (ExFreq) levels and chronic inflamma- tion and oxidative stress exists after making statistical adjustments for confounders including body mass index (BMI), age, gender, and cigarette smoking. Study partici- pants (60% female and 40% male; n = 998) varied widely in age (18–85 years) and BMI (16.7–52.7 kg/m 2 ) completed an extensive medical/health and lifestyle questionnaire, and data were used to establish pFIT and ExFreq tertiles. Biomarkers included serum C-reactive protein (CRP), total blood leukocytes, five plasma cytokines [interleukin (IL)-6, IL-10, tumor necrosis factor-a (TNF-a), monocyte chemoattractant protein-1 (MCP1), and granulocyte colony-stimulating factor (GCSF)], F 2-isoprostanes, ferric reducing ability of plasma (FRAP), and oxygen radical absorbance capacity (ORAC). A general linear model was used to examine relationships between pFIT and ExFreq with inflammation and oxidative stress while controlling for age, gender, BMI, and smoking. Benjamini–Hochberg method for false discovery rate correction was used for multiple testing corrections. Significant tests (P < 0.05) for trend were found for the effect of pFIT and ExFreq on CRP, white blood cell, IL-6, TNF-a, GCSF, and F 2-isoprostanes, but not MCP1, IL-10, FRAP, and ORAC, after adjustment for confounders. These data indicate that an inverse relationship exists among chronic inflam- mation, oxidative stress, and pFIT and ExFreq at the community level even after adjustment for important confounders. Physical inactivity has been linked to numerous chronic diseases or chronic disease risk factors (Booth et al., 2000). Atherosclerosis, type 2 diabetes, metabolic syn- drome, chronic obstructive pulmonary disease, arthritis, and osteoporosis are associated with chronic low-grade inflammation and oxidative stress (Morrow, 2005; Basu, 2008; Beavers et al., 2010). Physical activity has poten- tial benefits on systemic inflammation and oxidative stress biomarkers frequently employed to study the like- lihood of developing these disease states. The acute phase protein C-reactive protein (CRP) is the most fre- quently measured inflammation biomarker in physical activity-related studies, with others also analyzing total blood leukocytes [white blood cell (WBC)], cytokines interleukin (IL)-6, and tumor necrosis factor-a (TNF-a; Beavers et al., 2010). Few data are available on the relationship between physical activity and other inflammation-related cytokines such as granulocyte colony-stimulating factor (GCSF), monocyte chemoat- tractant protein-1 (MCP1), and the anti-inflammatory cytokine IL-10 (Suzuki et al., 2002). The linkage between physical activity and F 2 -isoprostanes, a widely used and highly regarded biomarker of oxidative stress, is also not well established (Morrow, 2005; Vincent & Taylor, 2006; Fisher-Wellman et al., 2009). Systemic inflammation and oxidative stress are at lower levels in groups with higher fruit and vegetable intake and lower body mass index (BMI; Esmaillzadeh et al., 2006; Vincent & Taylor, 2006; Selvin et al., 2007; Holt et al., 2009). The association of physical activity to inflammation and oxidative stress is equivocal (Vincent & Taylor, 2006; Fisher-Wellman etal., 2009; Beavers et al., 2010). Most randomized-controlled exercise- intervention studies have yet to demonstrate that inflammation and oxidative stress are decreased in the absence of weight loss despite increases in exercise capacity (Kelley & Kelley, 2006; Stewart et al., 2007; 2010; Arsenault et al., 2009; Beavers et al., 2010; Church et al., 2010; Thompson et al., 2010). Conversely, other well-controlled exercise training studies have Scand J Med Sci Sports 2011: ••: ••–•• doi: 10.1111/j.1600-0838.2011.01373.x © 2011 John Wiley & Sons A/S 1