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

Indiana University-Purdue University Indianapolis (IUPUI) / Rates of chronic disease and physical inactivity are disproportionately high among African American women. Despite the known benefits of physical activity and an increasing number of programs designed to increase activity, attendance rates to many exercise programs remain low. There is much to learn about program types, such as healthy lifestyle programs (HLP); individual factors, such as self-efficacy; and mediating variables that may influence exercise program attendance. An observational study design was used to compare exercise self-efficacy and attendance in a community-based exercise program in African American women who were enrolled in a HLP (N = 53) to women who were not (N = 27). Exercise program attendance was gathered across six months; demographics, self-efficacy and physical activity behaviors were assessed through surveys; and physiological variables (resting heart rate and blood pressure, height, and weight) and physical fitness (muscular strength and endurance and cardiovascular endurance) were measured at baseline. Descriptive statistics were used to describe participants and groups were compared using T-tests, chi-square and non-parametric statistics. Finally, mediation analyses were conducted using multiple regression models to assess self-efficacy as a potential mediator to exercise program attendance. Women who enrolled in this study were of low income (61% having an annual income less than $20,000), obese with a mean (standard deviation) body mass index (BMI) of 37.7 (7.6), pre-hypertensive with a mean (standard deviation) systolic blood pressure of 125.9 (14.4), and scored poorly and marginally on two fitness tests. On average, women reported being Moderately Confident in their ability to exercise regularly, yet had low attendance in the exercise program with a median number .5 days over six months and there were no significant differences in exercise self-efficacy (p = .23) or attendance in the exercise program between groups (p = .79). Additionally, exercise self-efficacy was not a mediating variable to program attendance. Women in this study had little discretionary income and several chronic disease risk factors, yet exercise program attendance was low even in those enrolled in a HLP. Identifying factors that increase exercise self-efficacy and factors that influence attendance beyond self-efficacy may help future program design and attendance.

Indiana University-Purdue University Indianapolis (IUPUI) / Gender differences in the basal function of autonomic cardiovascular control are well documented. Consistent baroreflex (BRx) studies suggest that women have higher tonic parasympathetic cardiac activation compared to men. Later in life and concomitant with menopause, a significant reduction in the capacity of the BRx in females increases their risk to develop hypertension, even exceeding that of age-matched males. Loss of sex hormones is but one factor. In female rats, we previously identified a distinct myelinated baroreceptor (BR) neuronal phenotype termed Ah-type, which exhibits functional dynamics and ionic currents that are a mix of those observed in barosensory afferents functionally identified as myelinated A-type or unmyelinated C-type. Interestingly, Ah-type afferents constitute nearly 50% of the total population of myelinated aortic BR in female but less than 2% in male rat. We hypothesized that an afferent basis for sexual dimorphism in BRx function exists. Specifically, we investigated the potential functional impact Ah-type afferents have upon the aortic BRx and what changes, if any, loss of sex hormones through ovariectomy brings upon such functions. We assessed electrophysiological and reflexogenic differences associated with the left aortic depressor nerve (ADN) from adult male, female, and ovariectomized female (OVX) Sprague-Dawley rats. Our results revealed sexually dimorphic conduction velocity (CV) profiles. A distinct, slower myelinated fiber volley was apparent in compound action potential (CAP) recordings from female aortic BR fibers, with an amplitude and CV not observed in males. Subsequent BRx studies demonstrated that females exhibited significantly greater BRx responses compared to males at myelinated-specific intensities. Ovariectomy induced an increased overall temporal dispersion in the CAP of OVX females that may have contributed to their attenuated BRx responses. Interestingly, the most significant changes in depressor dynamics occurred at electrical thresholds and frequencies most closely aligned with Ah-type BR fibers. Collectively, we provide evidence that, in females, two anatomically distinct myelinated afferent pathways contribute to the integrated BRx function, whereas in males only one exists. These functional differences may partly account for the enhanced control of blood pressure in females. Furthermore, Ah-type afferents may provide a neuromodulatory pathway uniquely associated with the hormonal regulation of BRx function.