Human Movement Science Programme, Faculty of Social Sciences and Technology Management, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
BACKGROUND Changes in the state of energy balance owing to changes in physical activity may affect the reproductive system. We evaluated the association between physical activity (PA) and fertility and parity in healthy women. METHODS A population-based health survey (HUNT 1) was conducted during 1984-1986 in Nord-Trøndelag county, Norway, with follow-up from 1995 to 1997 (HUNT 2). The study included 3887 women,