The effects of moderate exercise on dietary intake, iron status, and cardiovascular endurance of 56- to 67-year-old women

TR Number



Journal Title

Journal ISSN

Volume Title


Virginia Tech


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.