Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Fall 12-18-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Health Sciences

Advisor(s)

David Wenos

Abstract

The physical activity recommendation for U.S. adults is to engage in moderate-intensity exercise for at least 150 minutes per week. Pedometers have gained popularity as a tool for motivating and estimating daily physical activity. Recently it was suggested 3000 steps in 30 minutes may be equivalent to moderate-intensity walking. To date, this recommendation has yet to be examined over an extended period of time. PURPOSE: To evaluate changes in cardiorespiratory fitness, body composition, blood lipids, blood glucose, and CRP from 150 minutes of free living weekly exercise compared to pedometer measured 3000 steps in 30 minutes, five days per week. METHODS: Subjects were randomly divided into two interventions (free living and pedometer) for 12 weeks. A free living (FL) group (n=12) accumulated 150 minutes moderate-intensity physical activity per week. A pedometer (P) group (n=13) attended three 30-min supervised walking sessions and walked two 30-min sessions independently. Metabolic variables were measured pre- and post-intervention. RESULTS: Twenty-five subjects began the study and nineteen FL (n=8) and P (n=11) subjects completed the study. Adherence was 77.9% and 85.2% in FL and P groups, respectively. SBP (-8.24 ± 11.3; p < 0.05) and glucose (-7.2 ±11.8mg/dl; p < 0.05) were significantly lower in P pre/post. Mean changes in CRP (-1.6 mg/dl, p = 0.11), LM (0.14 kg, p = 0.19), and VO2max (1.6 mg/kg/min, p = 0.2) approached significance in P only. In contrast, FL pre/post measurements did not significantly differ in any parameter. HR, BP, GLU, LM, and BMD improved in both groups. CRP and VO2max improved in P only. CONCLUSION: Evidence suggests the general recommendation of 150 minutes per week does not successfully improve metabolic variables or promote adherence. Additionally, there is a dose response to 3000 steps in 30 minutes on metabolic variables compared with 150 minutes per week. This gives a practical application for the use of pedometers and metronomes to monitor intensity and motivate adherence. Further, results indicate walking 3000 steps in 30 minutes is an appropriate proxy for meeting the 150 minutes per week recommendation.

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