Effectiveness of three different walking prescription durations on total physical activity in normal- and overweight women

Abstract

Objective: While there is a dose-response relationship between physical activity (PA) and health benefit, little is known about the effectiveness of different PA prescriptions on total daily PA.

Aim: To test, under real-life conditions and using an objective, non-invasive measurement technique (accelerometry), the effect of prescribing additional physical activity (walking only) of different durations (30, 60 and 90 min/day) on compliance (to the activity prescribed) and compensation (to total daily PA). Participants in each group were prescribed 5 sessions of walking per week over 4 weeks.

Methods: 55 normal-weight and overweight women (mean BMI 25 ± 5 kg/m(2), height 165 ± 1 cm, weight 68 ± 2 kg and mean age 27 ± 1 years) were randomly assigned to 3 prescription groups: 30, 60 or 90 min/day PA.

Results: Walking duration resulted in an almost linear increase in the number of steps per day during the prescription period from an average of about 10,000 steps per day for the 30-min prescription to about 14,000 for the 90-min prescription. Compliance was excellent for the 30-min prescription but decreased significantly with 60-min and 90-min prescriptions. In parallel, degree of compensation subsequent to exercise increased progressively as length of prescription increased.

Conclusion: A 30-min prescription of extra walking 5 times per week was well tolerated. However, in order to increase total PA further, much more than 60 min of walking may need to be prescribed in the majority of individuals. While total exercise 'volume' increased with prescriptions longer than 30 min, compliance to the prescription decreased and greater compensation was evident.

© 2014 S. Karger GmbH, Freiburg.

Figures

Fig. 1

Experimental design. Note the double baseline periods before and after intervention (2 weeks each), allowing first a comparison of activity between the 2 baseline periods and second the ability to track any continuation of walking (carry over) beyond the completion of the 4-week physical activity prescription.

Fig. 2

Total number of steps over 24 h during the baseline, prescription periods (first and second) and post-prescription periods. Values are shown as mean ± SEM. **p #p < 0.05 versus 30-min prescription.

Fig. 3

Net increase in walking duration (over baseline) during the first and second walking prescription period (2 weeks each). Dotted lines represent the 3 durations prescribed. Values are shown as mean ± SEM.

Fig. 4

Relative compliance (adherence) to walking prescription during each walking prescription period. Values are shown as mean ± SEM.

Fig. 5

Relative compensation (%) to walking prescription. Values are shown as mean ± SEM. #p < 0.05 versus 30-min prescription.

Fig. 6

AEE. Values are shown as mean ± SEM. **p #p < 0.05 versus 30-min prescription.