Influence of walking volume on health benefits in women post-menopause.

The health benefits of physical activity are believed to be related more to exercise volume than to intensity. In this 24-wk study, we examined the effect of walking volume on aerobic fitness, serum lipids, and body composition in women post-menopause, a population at risk for coronary artery disease. Of 79 women randomly assigned to groups at the outset, 56 completed the study (mean age 61.3 +/- 5.8). Participants walked at an intensity of 60% peak oxygen uptake (VO2peak) for 60 min, 3 d.wk-1 (N = 19) or 5 d.wk-1 (N = 17), or remained sedentary (N = 20). Walking 3 or 5 d.wk-1 increased VO2peak (ml.kg-1.min-1) by 12% and 14%, respectively (P < 0.01). There were no changes in serum lipids in response to either program. Percent body fat decreased by 1.1% and 1.3% in those walking 3 and 5 d.wk-1, respectively; both changes significantly different from the control group (P < 0.05). Walking 5 d.wk-1 did not result in more health benefits than 3 d.wk-1, possibly due to a greater compensatory decline in activities other than the walking program, or greater discrepancies between actual and reported activity and food intake. Longer-duration programs, or simultaneous changes in diet, may be necessary to alter serum lipids in nonobese, normo-lipidemic women post-menopause.

Serum ferritin and heart disease: the effect of moderate exercise on stored iron levels in postmenopausal women.

OBJECTIVE: To determine the effect of a moderate exercise regimen on stored iron as measured by serum ferritin in previously sedentary postmenopausal women. DESIGN: Randomized assignment to one of three groups: a five day/week walking group (five-day group, n = 27); a three day/week walking group (three-day group, n = 27) or a sedentary group (control group, n = 25). SETTING: Community-based intervention. PARTICIPANTS: Women who were postmenopausal, over 50 years old, sedentary, not on hormone replacement therapy, nonsmokers, physically capable of exercising, without clinical signs of cardiovascular, pulmonary or metabolic disease, and not on medication that would affect iron metabolism. In addition, they had neither donated blood nor been transfused within the previous 12 months. All participants were screened volunteers who had responded to media advertisements. Seventy-nine participants met these criteria. Results are reported for 56 subjects (five-day group, n = 17; three-day group, n = 19; control group, n = 20) who completed the study. Their mean age was 61.3 +/- 5.8 years. INTERVENTION: The five-day group and the three-day group walked an average of 279 +/- 20 and 171 +/- 7 mins/week, respectively. Participants were counselled not to change their dietary intake. MAIN RESULTS: Following 24 weeks of walking, mean serum ferritin decreased significantly in the five-day group (P < 0.03), but not in the three-day group (P < 0.09) compared with controls. CONCLUSIONS: The extent of physical activity required to elicit a decrease in stored iron in postmenopausal women was determined. This may be clinically significant because stored iron increases significantly following menopause and excess stored iron have been cited as risk factors for coronary artery disease.