Review of the Relationship between C-Reactive Protein and Exercise

C-reactive protein (CRP), an acute phase reactant, is associated with systemic inflammation. Many studies have demonstrated that CRP levels have important prognostic implications for patients. For example, individuals with elevated CRP levels have an increased risk of cardiovascular events. The JUPITER study showed that reducing CRP levels can mitigate this risk. Various trials have investigated the effect of lifestyle modifications on serum CRP levels. Specifically, the impact of different exercise-based protocols on CRP levels has been researched. This review article evaluates the response of CRP levels to aerobic-based, resistance-based, and combination exercise protocols. Furthermore, it examines the impact of such regimens in children, adults, and the elderly. No definitive answers exist regarding the relationship between exercise and CRP levels. Significant reductions in CRP levels were noted in 11 of 25 trials of aerobic-based regimens, two of five studies of combination protocols, and neither of two trials of resistance-based regimens. Similar findings were seen across all age groups. There were significant CRP reductions in nine of 18 adult studies, four of ten child studies, and one of three elderly studies. Mixed results reflect uncertainty about the ability of exercise to reduce inflammation. Various mechanisms, including increased protein synthesis and fat loss, have been proposed to explain the potential anti-inflammatory effects of exercise. While exercise-based regimens have produced inconsistent results, lifestyle modifications do appear to have significant anti-inflammatory effects. This was particularly evident in studies that utilized combined diet/exercise programs. Significant CRP reductions were seen in five of seven such trials. Interestingly, both studies with failed combination protocols achieved substantial CRP reductions in their diet-only groups. These findings suggest that weight loss is important in reducing inflammation. Additionally, they indicate that combined diet/exercise protocols should be part of any lifestyle intervention program. Further research will be needed to identify optimal regimens for achieving anti-inflammatory benefits.