A relationship between increasing levels of vigorous exercise and longer times to conception in healthy, normal weight women who are planning to become pregnant was found by Danish and US researchers.
There was evidence for a dose-response relationship between increasing vigorous physical activity and delayed time to pregnancy in all subgroups of women with the exception of overweight and obese women. Moderate physical activity was associated with a small increase in fecundability regardless of body mass index (BMI).
These findings indicate that physical activity of any type might improve fertility among overweight and obese women, a subgroup at higher risk of infertility. Lean women who substitute vigorous physical activity with moderate physical activity may also improve their
fertility.
The observational prospective cohort study used the internet to recruit and administer questionnaires to 3628 women, age 18 to 40. Participants were required to be in stable relationships with male partners, planning to become pregnant, and not receiving any fertility
treatments.
The women were given baseline questionnaires to gather information on their demographics, height, weight, reproductive and medical history, lifestyle, and behavior. Eighty-three percent completed the study.
One of the things the women were asked at baseline was the average number of hours per week they exercised. In addition, they were asked to report different types of moderate and vigorous activity
separately.
Activities such as running, fast cycling, aerobics, gymnastics, and swimming were characterized as vigorous.
Brisk walking, leisurely cycling, golfing and gardening were considered moderate.
Assigning values - total metabolic equivalents (METs) - to the activities, the researchers quantified the amount of moderate and vigorous physical activity each participant engaged in.
The researchers found that there was an inverse association between vigorous physical activity and how long it took to become pregnant for normal weight women (BMI under 25). In overweight or obese women (BMI of 25 or above) there was no association between vigorous exercise and a longer time to
pregnancy.
ASRM President-Elect, Linda Giudice, MD, PhD, noted that this study is particularly interesting because its participants were recruited from the general population, not from infertility patients. All women who are planning a pregnancy might reduce their time to pregnancy by modulating their exercise
programs.”
The American Society for Reproductive Medicine, founded in 1944, is an organization of 8,000 physicians, researchers, nurses, technicians and other professionals dedicated to advancing knowledge and expertise in reproductive biology. Affiliated societies include the Society for Assisted Reproductive Technology, the Society for Male Reproduction and Urology, the Society for Reproductive Endocrinology and Infertility, the Society of Reproductive Surgeons, and the Society of Reproductive Biologists and
Technologists.
Source
A prospective cohort study of physical activity and time to pregnancy
(MDN)
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