ENERGY COST OF PHYSICAL ACTIVITIES DURING PREGNANCY

Abstract

General guidelines have been established for physical activity during pregnancy however the dose of physical activity resulting in optimal fetal outcomes is unknown. Past recommendations are based on poor, non-specific physical activity measures not tailored to encompass the potential changes in energy expenditure seen during pregnancy. Metabolic and mechanical energy demands increase during pregnancy due to fetal growth, with physiologic adaptations occurring in response to this increase. Thus, the purpose of this study was to assess the energy expenditure required to perform selected activities, and to determine if energy expenditure changes across trimesters of pregnancy. A second purpose was to compare our observed METs to the MET levels reported by the Compendium of Physical Activities (CPA). METHODS: 30 pregnant women (trimester 1 (T1):n = 6, trimester 2(T2):n = 14, trimester 3 (T3):n = 10) performed four common household tasks (window washing, dusting, vacuuming, laundry), and completed three bouts of overground walking at a range of self-selected speeds. Energy expenditure was measured using the TEEM100 (Medgraphics, MI). RESULTS: No significant differences were found in METs for any of the activities across the trimesters. Overall METs for window washing, vacuuming, and brisk walking were lower than the corresponding values from the CPA by 40%, 22%, and 9% respectively, while MET values for dusting, laundry, and light and moderate walking were higher than the CPA by 9%, 42%, 6%, and 14%, respectively. Mean METs for all tasks ranged from 2.5–3.3, while mean METs across walking speeds ranged from 3.2–4.6. CONCLUSION: MET values for various common activities did not increase with increasing gestational age during pregnancy. The CPA overestimates energy costs of light household tasks including window washing and vacuuming, and underestimates the energy cost of doing laundry for pregnant women. Energy expenditure for walking at a brisk speed during pregnancy is overestimated by the CPA. Supported by NIH RO3-HD 39341