Abstract P028: The Influence of Exercise Dose, Exercise Intensity, and Weight Loss on C-reactive Protein in Sedentary Overweight Women

Abstract

Background: Obesity is a modifiable risk factor associated with heart disease and an increased inflammatory state. Reducing weight and increasing physical activity have been shown to decrease heart disease risk. There is increasing evidence that weight loss leads to a reduced inflammatory state; however, there is less evidence on the combined role of weight loss and different doses of exercise. Objective: The purpose of the study was to examine the effect of exercise on change in high sensitivity C-reactive protein (hs-CRP) in overweight and obese women in a 6-month behavioral weight loss program. Methods: The parent study was a randomized trial testing different doses of exercise in a behavioral weight loss program. The sample (N = 182) consisted of sedentary overweight women with a mean (SD) age of 37.5 (±5.7) years and a baseline body mass index (BMI) of 32.7 (±4.2) kg/m 2 . Participants were randomly assigned to 1 of 4 exercise groups based on energy expenditure (1000 kcal/week or 2000 kcal/week) and intensity (vigorous vs. moderate). Groups included: vigorous intensity/high dose; vigorous intensity/moderate dose; moderate intensity/moderate dose; and moderate intensity/high dose. The dietary component included an energy restricted diet of 1200 kcal/day or 1500 kcal/day based on weight at baseline; daily fat intake recommendation was 20%-30% of total energy intake. Results: There were no statistically significant differences in hs-CRP levels between dose of exercise, moderate vs. high, (F=0.330, p=0.58) or level of intensity, moderate vs. vigorous (F=0.118, p=0.731). However, there was a significant decrease in hs-CRP from baseline to 6 months (F=25.553, p<0.0004). There was a significant 3 way interaction between energy expenditure, intensity, and time (baseline to 6-month) (F=4.035, p=0.035); post hoc analysis revealed a significant decrease in hs-CRP in the moderate/high (p<0.0004) and vigorous/moderate groups (p=0.004). The results were unchanged after controlling for the change in body weight, body fatness, or body distribution. The change in hs-CRP was not significantly correlated with the change in body weight, percent body fat, waist circumference, or self-reported physical activity. The hs-CRP at 6 months was correlated with 6-month measures of weight, BMI, percent body fat, and fat distribution (p<0.0004). Conclusions: The level of hs-CRP was reduced in overweight and obese women in response to a 6-month weight loss intervention that included a prescribed increase in energy expenditure and reduction in energy intake. We observed a significant reduction in the moderate intensity/high dose and vigorous intensity/moderate dose exercise groups, suggesting that at least a moderate level of exercise is needed to affect hs-CRP levels. Further research is needed to better determine the dose of exercise needed to reduce markers of inflammation.