AN INVERSE ASSOCIATION BETWEEN REGULAR PHYSICAL ACTIVITY AND PLASMA MALONDIALDEHYDE 1698

The relation of physical activity (PA) to the plasma malondialdehyde (MDA) level was analyzed in 150 men, aged 53 to 63 years. PA was assessed by a 7-day recall interview, maximal oxygen uptake (˙VO2max) using breath-by-breath respiratory gas analyses during a maximal, symptom limited exercise test, and MDA concentration colorimetrically. Conditioning physical activity (cPA, >5 METs) and ˙VO2max correlated inversely(r=-0.24, p=0.003 and r=-0.23, p=0.005, respectively), and waist-to-hip -ratio(WHR) positively (r=0.34, p<0.001) with plasma MDA level. Compared to non-smokers, current smokers had higher MDA level [12.5 (SD 1.2) vs. 13.3(1.3) μmol/1, p=0.002]. Of the high density lipoproteins (HDL), apolipoprotein AI concentration in the HDL-2b subfraction showed the strongest association with MDA (r=-0.31, p<0.001). When the men were divided into three classes according to their cPA level (0, 0.1-3.5 and >3.5 METh/day), the subjects in the highest cPA category (n=35) had lower MDA level than the men (n=71) with no cPA [12.1 (1.3) vs. 12.9 (1.2) μmol/l, p=0.007]. The difference remained significant (p=0.037) after adjustments for WHR, smoking and HDL-2b apo AI level. The present data suggest that regular physical activity of moderate intensity may improve the antioxidant status, and protect against free radical formation even in the status of an increased physical activity.