Response of high-sensitivity C-reactive protein to exercise training in an at-risk population.
BACKGROUND
High-sensitivity C-reactive protein (hsCRP) is promoted as an independent predictor of atherosclerotic risk. In addition, cardiorespiratory fitness is inversely related to hsCRP in single-sex cross-sectional analyses. Our objective was to determine if modulating fitness with exercise training imposes changes in high-sensitivity C-reactive protein in a mixed-sex population at risk for cardiovascular disease.


METHODS
We studied baseline and postintervention plasma hsCRP in 193 sedentary, overweight to mildly obese, dyslipidemic men and women who were randomized to 6 months of inactivity or 1 of 3 aerobic exercise groups: low amount-moderate intensity (energy equivalent of approximately 19.3 km/wk at 40%-55% peak VO2), low amount-high intensity (energy equivalent of approximately 19.3 km/wk at 65%-80% peak VO2), or high amount-high intensity (energy equivalent of approximately 32.2 km/wk at 65%-80% peak VO2).


RESULTS
At baseline, the study population was at intermediate to high cardiovascular risk as defined by hsCRP. Cardiorespiratory fitness was inversely related to hsCRP (P < .001) even after adjusting for significant and expected sex differences. Fitness, hormone replacement therapy use, and high-density lipoprotein cholesterol accounted for the sex difference in baseline hsCRP. Fitness, high-density lipoprotein cholesterol, fasting insulin, hormone replacement therapy, and visceral adiposity were all independent predictors for baseline hsCRP (r2 = 0.34 for the entire model, P < .0001). However, despite significant improvements in fitness, visceral adiposity, subcutaneous adiposity, and insulin sensitivity, hsCRP did not change in response to exercise training (P > .20).


CONCLUSIONS
Cardiorespiratory fitness is inversely related to hsCRP independent of sex and accounts for most of the large sex disparity in hsCRP. Nonetheless, in the absence of a significant change in diet, 6 months of aerobic exercise training does not produce a significant change in hsCRP in an at-risk population.
Huffman
Kim M
KM
Division of Rheumatology, Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA. kim.huffman@duke.edu
Samsa
Gregory P
GP
Slentz
Cris A
CA
Duscha
Brian D
BD
Johnson
Johanna L
JL
Bales
Connie W
CW
Tanner
Charles J
CJ
Houmard
Joseph A
JA
Kraus
William E
WE
D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000209:etiology*; D008076:Cholesterol, HDL / Q000097:blood; D005260:Female; D006321:Heart / Q000502:physiology; D020249:Hormone Replacement Therapy; D006801:Humans; D050152:Intra-Abdominal Fat / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010806:Physical Education and Training; D010809:Physical Fitness; D012119:Respiration; D012307:Risk Factors; D012727:Sex Characteristics
D008076:Cholesterol, HDL; D002097:C-Reactive Protein