The effects of strength training and high exercise on the iron status of young women

William Richard Proulx, Purdue University

Abstract

The purpose of this study was to study the impact of a moderate exercise program on the iron status of sedentary college-age women. A group of 18-30 year old women (n = 49) were randomly assigned to an exercise (n = 22) or control (n = 27) group. Exercise included a circuit training program of resistance exercise alternated with bicycle ergometer 3 times per week. Additionally subjects were asked to jump rope for 60 minutes per week. Serum ferritin, serum iron, total iron binding capacity (TIBC), transferrin saturation, hemoglobin, hematocrit and serum albumin were measured at baseline and every 6 months for 18 months. Subject completed activity logs were monitored to determine exercise compliance. Nutritional intake was estimated using 3 day diet records completed at baseline and every six months. Only dietary fat intake was found to be significantly different between the exercisers and controls at baseline. Compliance to the 18 month exercise program averaged 1.56 times per week for circuit training and 37.49 minutes per week for jumping rope. Results of hemoglobin, hematocrit, serum iron, transferrin saturation and serum ferritin indicated that iron status was not compromised by the exercise program. Although the level of compliance may have been insufficient to impact iron status, the type and frequency of the activity was sufficient to increase lean mass in the exercisers. Significant (p $<$ 0.05) differences in lean mass were observed between the groups at 12 and 18 months with exercisers experiencing significant increases in lean mass from baseline values. Also, exercise lead to significant increases in body weight in the exercisers compared to the controls at 6, 12 and 18 months (p $\le$ 0.05). Estimations of the nutritional intake of the exercisers indicated a high intake of iron (14.05 mg/day) and vitamin C (111 mg/day) and a low intake of fiber (10 g/day) throughout the study. Controls consumed significantly lower amounts of iron (11.7 mg/day) but vitamin C and fiber intake were similar to exercisers. Also, 77% of the exercisers (17/22) versus 52% (14/28) of the controls used oral contraceptives throughout the study possibly decreasing menstrual blood flow which would help improve iron balance. Therefore, we conclude that sedentary college-age women who initiate an exercise program consisting of resistance training (1 to 2 times per week) and a high impact exercise such as jumping rope (30 minutes per week) while maintaining a high dietary intake will not compromise their iron status.

Degree

Ph.D.

Advisors

Weaver, Purdue University.

Subject Area

Nutrition|Sports medicine

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