Strikingly low circulating CRP concentrations in ultramarathon runners independent of markers of adiposity: how low can you go?
OBJECTIVE
This study was undertaken to evaluate to what extent C-reactive protein (CRP) can be reduced by exercise by examining its circulating concentrations in male ultramarathon runners and to determine if low leptin as a robust circulating marker of fat mass could account for low CRP in such men.


RESULTS
Sixty-seven male ultramarathon runners and 63 sedentary male controls of similar age and body mass index were recruited. CRP and leptin were measured by ELISA and radioimmunoassay, respectively. Median CRP concentration in lean (body mass index <25 kg/m2) marathon runners was less than half control median (0.4 [0.2 to 0.9] mg/L versus 0.9 [0.5 to 2.7] mg/L, P=0.0013) and, more strikingly, in nonlean runners was approximately 26% of control median (0.4 [0.3 to 0.8] mg/L versus 1.5 [0.9 to 2.5] mg/L, P=0.0002). Circulating leptin levels were also substantially lower in lean (45% less) and nonlean (63% less, both P<0.0001) ultramarathon runners. However, interleukin-6 levels were not different. Furthermore, leptin adjustment only minimally attenuated the case-control difference in CRP, suggesting that mechanisms other than fat mass reduction contribute to low concentrations of CRP in marathon runners.


CONCLUSIONS
This study suggests that circulating CRP concentrations can be markedly suppressed, independently of total adiposity or indeed fat mass, by intense regular physical exercise.
Tomaszewski
Maciej
M
British Heart Foundation Glasgow Cardiovascular Research Centre, Division of Cardiovascular and Medical Sciences, University of Glasgow, UK. mt65@clinmed.gla.ac.uk
Charchar
Fadi J
FJ
Przybycin
Malgorzata
M
Crawford
Lynne
L
Wallace
A Michael
AM
Gosek
Katarzyna
K
Lowe
Gordon D
GD
Zukowska-Szczechowska
Ewa
E
Grzeszczak
Wladyslaw
W
Sattar
Naveed
N
Dominiczak
Anna F
AF
D000328:Adult; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology*; D019040:E-Selectin / Q000097:blood; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D020738:Leptin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D012420:Running / Q000502:physiology*
D015415:Biomarkers; D019040:E-Selectin; D015850:Interleukin-6; D020738:Leptin; D018799:Intercellular Adhesion Molecule-1; D002097:C-Reactive Protein