Reduction of the plasma concentration of C-reactive protein following ninemonths of endurance training

An intense physical exercise induces an inflammatory reaction as demonstrat ed by the delayed increase in brood of acute phase proteins and among them of C-reactive protein (CRP). There is also evidence for a diminished acute phase reaction due to regular exercise suggesting a suppression of the infl ammatory response through training. With this background CRP was measured b y a sensitive enzyme immunoassay under resting conditions before and after 9 months of training in 14 subjects preparing for a marathon with the aim o f studying the effect of training on the base-line CRP concentration. The m ean distance run per week increased significantly from 31 +/- 9 km at the b eginning to 53 +/- 15 km after 8 months of training (p < 0.01). The aerobic capacity rose significantly after training as demonstrated by the increase of Funning velocity during a maximal treadmill test from 3.82 +/- 0.29 m/s pre-training to 4.17 +/- 0.17 m/s post-training at a blood lactate concent ration of 4 mmol/L (p < 0.01). In 10 of 12 runners base-line CRP was dimini shed after training in spite of a continuous increase of training intensity . The CRP median fell from 1.19 mg/L before to 0.82 mg/L after training (p < 0.05). Since intense physical exercise is known to be associated with an inflammatory reaction of muscles and tendons, the CRP decrease was unexpect ed. In 2 subjects the CRP concentration rose markedly because of a borrelia infection and a knee injury, respectively. These values were caused by a p athological condition and were not considered for the statistical evaluatio n. In 10 non-training control subjects the CRP median did not change signif icantly during the same 9 months period. The decrease of the CRP base-line concentration after training suggests that intensive regular exercise has a systemic anti-inflammatory effect. This is of particular interest with reg ard to several recent reports confering on the concentration of CRP in plas ma a predictive value for the risk of cardiac infarction, Venous thrombosis or stroke.