Exercise training is thought to result in an elevation of high-density lipoprotein (HDL) and the cardioprotective subfraction HDL{dollar}\sb2{dollar}. Twenty-five healthy women (39 {dollar}\pm{dollar} 7.8 yrs; 70 {dollar}\pm{dollar} 14 kg) walked two miles three times per week for 12 weeks to examine the effect of exercise intensity on the HDL profile. The L.I. group (N = 12) walked at 60% of the heart rate reserve (HRR) and the H.I. group (N = 13) walked at 80% HRR both maintaining the prescribed distance and frequency. A 22% increase in total HDL (from 32 {dollar}\pm{dollar} 6 to 39 {dollar}\pm{dollar} 8 mg/dl) and a 35% increase in HDL{dollar}\sb2{dollar} (from 14 {dollar}\pm{dollar} 3 to 19 {dollar}\pm{dollar} 9 mg/dl) was elicited as a result of the walking program (p {dollar}\u3c{dollar}.005). Slight increases in HDL{dollar}\sb3{dollar} were also observed. However, no significant differences in total HDL or HDL{dollar}\sb2{dollar} were observed between the L.I. and H.I. groups. These findings demonstrate an exercise induced enhancement of the cardioprotective mechanism thought to be associated with the HDL{dollar}\sb2{dollar} subfraction. Moreover, it appears that walking at 80% of the HRR offers no advantage over walking at 60% of the HRR in enhancing the HDL profile
