Energy cost of walking at a fixed pace and self-paced before, during, and after pregnancy

Abstract

Body weight, basal metabolic rate (BMR), and treadmill metabolic rate (TMR) (3.9 km/h, no elevation) were measured in 39 women at 12, 24, and 36 wk gestation and at 9 wk postpartum. Prepregnancy measurements were also made on 15 of the women. TMR at 36 wk (3.65 +/- 0.50 kcal/min) was significantly higher than at 24 wk (3.38 +/- 0.43 kcal/min) or at 9 wk postpartum (3.38 +/- 0.43 kcal/min). Net energy cost (TMR minus BMR) at 36 wk gestation (2.42 +/- 0.40 kcal/min) was not different from prepregnancy or postpartum values but was significantly higher than at 12 wk (2.28 +/- 0.39 kcal/min) and 24 wk (2.28 +/- 0.37 kcal/min) gestation. In eight women the energy cost of self-paced walking on a treadmill was measured. The absolute and net energy cost decreased sharply from 6 to 12 wk gestation (by 8% and 11%, respectively) but remained unchanged afterwards. The data suggest that in the energy requirements for pregnant women no additional allowance need be made for physical activity, even if a woman's activity pattern includes a substantial amount of externally paced work.