Abstract 6209: Cross-sectional and Longitudinal Association of Cardiorespiratory Fitness with F2 Isoprostanes: CARDIA
Cardiorespiratory fitness (CRF) is inversely associated with cardiovascular disease (CVD) through a number of established and emerging mechanisms. Clinical studies report less oxidative damage with higher levels of physical activity; thus, oxidative stress is a plausible mechanism in the pathway between CRF and CVD. We investigated whether CRF and its changes in the preceding 20 years were each inversely associated with F2-isoprostanes (ISOP), a marker of oxidative stress, measured concurrently with the later CRF measure. Coronary Artery Risk Development in Young Adults (CARDIA) Study participants had ISOP measured by gas chromatography in 2005–06 (men=995, women=916). At the baseline (1985–86) and Year 20 (2005–06) exams, participants underwent symptom-limited graded exercise treadmill testing (GXT) using a modified Balke protocol. GXT duration (minutes) was our primary marker of fitness. Percentage of change in fitness over 20 years is defined as: (baseline GXT duration - Year 20 duration)/baseline duration. Covariates were measured at year 20. At Year 20, mean ISOP was 49.2 ng/L (SD=19.5) in men and 66.5 ng/L (SD=38.2) in women. Mean Year 20 GXT duration was 8.6 (SD=2.4) min in men and 6.1 (SD=2.4) min in women; year 20 CRF was 19% (SD=29) and 16% (SD=33) lower (% of baseline CRF) in men and women, respectively. CRF at year 20 and 20-year change in CRF were both inversely associated with ISOP in men and women (Table⇓) following adjustment for BMI and other CVD risk factors. CRF and increases in CRF over 20 years were inversely associated with ISOP in men and women independent of BMI and other established CVD risk factors. Future studies should test whether oxidative stress falls in the causal pathway between CRF and CVD morbidity and mortality.