Effects of Exercise on C-Reactive Protein in Sedentary Smokers and Non-smokers

Abstract

Studies report physical activity decreases inflammatory markers such as high sensitivity C-reactive protein (hsCRP). However, little research has been done on the effects of physical activity on hsCRP in a sedentary smoking population. PURPOSE: To determine if a walking program using walking poles and/or pedometers will show a decrease in hsCRP in sedentary smokers(S) and non- smokers(NS). METHODS: 17 female (40.5 + 8.7 yrs, 164.1 + 7.2 cm, 76.9 + 19.4 kg) and 2 male (53 yrs, 180.3 + 7.2 cm, 91.4 + 15.3 kg) subjects were chosen based on sedentary status determined by CDC/ACSM Physical Activity Guidelines. S and NS subjects were assigned to one of two exercise modes and accumulated at least 90 minutes of walking per week for 8 weeks. Volitional VO2 max, hsCRP, blood lipids, and body fat (%bf) were measured at orientation (Wk0) and week 8 (Wk8). Subjects recorded walking time and number of steps taken each week, and completed a 3-day diet record at Wk0 and Wk8. A repeated measures design was used to determine differences (p<0.05) between the S and NS groups at Wk0 and Wk8. An independent t-test was used to determine the difference in walking time and steps taken between S and NS. RESULTS: Overall hsCPR was significantly higher in S when compared to NS (p=0.008). There was a significant interaction between Wk0 and Wk8 for hsCRP in S and NS (p=0.027). HsCRP decreased in NS and increased in S after Wk8. There was a significant difference in overall TC/HDL ratio between S and NS (p=0.021) with NS having a lower TC/HDL Ratio. Total Cholesterol (TC), LDL, and %bf were higher in S overall. TC and LDL decreased in NS and increased in S over the 8 weeks. VO2max and HDL were higher in NS overall. Saturated fat intake increased after Wk8 for both S and NS, but NS tend to consume less. These trends were not statistically significant. There was no difference in walking time or steps taken between S and NS. CONCLUSIONS: HsCRP levels increased in the smoking population after wk8. Normally hsCRP levels lower after long term exercise but this has not been reported for smokers. This suggests that the activity for S may have elicited an inflammatory response for a sedentary (mean 27.01 + 5.1VO2 max) population. Future research should determine if hsCRP responds differently in a sedentary smoking population if a prescribed intensity level is monitored in a long term exercise program.