Physical activity pattern and activity energy expenditure in healthy pregnant and non-pregnant Swedish women.

BACKGROUND/
OBJECTIVES: Energy costs of pregnancy approximate 320  MJ in well-nourished women, but whether or not these costs may be partly covered by modifications in activity behavior is incompletely known. In healthy Swedish women: (1) to evaluate the potential of the Intelligent Device for Energy Expenditure and Physical Activity (IDEEA) to assess energy expenditure during free-living conditions, (2) to assess activity pattern, walking pace and energy metabolism in pregnant women and non-pregnant controls, and (3) to assess the effect on energy expenditure caused by changes in physical activity induced by pregnancy. SUBJECTS/
METHODS: Activity pattern was assessed using the IDEEA in 18 women in gestational week 32 and in 21 non-pregnant women. Activity energy expenditure (AEE) was assessed using IDEEA, as well as using the doubly labelled water method and indirect calorimetry.
RESULTS: AEE using the IDEEA was correlated with reference estimates in both groups (r=0.4-0.5; P<0.05). Reference AEE was 0.9 MJ/24 h lower in pregnant than in non-pregnant women. Pregnant women spent 92 min/24 h more on sitting, lying, reclining and sleeping (P=0.020), 73 min/24 h less on standing (P=0.037) and 21 min/24 h less on walking and using stairs (P=0.049), and walked at a slower pace (1.1 ± 0.1 m/s versus 1.2±0.1 m/s; P=0.014) than did non-pregnant controls. The selection of less demanding activities and slower walking pace decreased energy costs by 720 kJ/24 h and 80 kJ/24 h, respectively.
CONCLUSION: Healthy moderately active Swedish women compensated for the increased energy costs of pregnancy by 0.9 MJ/24 h. The compensation was mainly achieved by selecting less demanding activities.