The purpose of this study was to determine the effects of moderate exercise on iron status, dietary intake and cardiovascular fitness in 56- to 67-year-old women. Women 56- to 67-years-old were randomly assigned to two groups: exercise (n=8) or non-exercise (n=9) groups. Women in the exercise group cycled on an ergometer three days/week, 30 minutes/session at 70-75% maximal heart rate for 10 consecutive weeks. At weeks 0 and 11, submaximal treadmill stress tests were obtained to determine cardiovascular fitness level. Venous blood samples were also obtained at weeks 0 and 11 to determine serum ferritin, transferrin saturation, serum iron, total iron-binding capacity, hematocrit and hemoglobin concentrations. Three-day dietary and activity records were obtained from each subject at weeks 0 and 10. Using paired t-tests for statistical analysis, the data indicated a significant increase in time to reach 70% maximum heart rate (p<0.001), a significant decrease in average heart rate/grade (p<0.05) and a significant increase in hemoglobin concentrations (p<0.01) in the exercise group at week 11. Student t-tests indicated significant differences between the groups in hemoglobin concentration at week 0 (p<0.005) and hematocrit concentration at weeks 0 and 11 (p<0.05). The exercise group had significantly lower vitamin C and monounsaturated fatty acid intake than the non-exercise group at week 0 (p<0.05). No other significant differences in nutrient intakes were observed between or within the two groups. Caloric intakes varied widely between the two groups, ranging from 1223.0 ± 248.4 to 1533.3 ± 480.8 kcal at weeks 0 and 10 in the exercise group; 1270.1 ± 376.3 to 1348.7 ± 334.8 kcal in the non-exercise group. Intakes of zinc were less than 70% of the 1989 RDA in both groups, ranging from 56.9 ± 14.6 to 66.6 ± 16.3 percent. The results indicate that moderate exercise does not significantly change the dietary intake and all parameters of iron status but enhances the cardiovascular fitness level in 56- to 67-year-old women. / Master of Science