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Reuters--Moderate exercise is tied to greater success among womentrying to get pregnant, but those who work out vigorously takelonger to conceive, an international study has found. This study is the first to find that the effect of physicalactivity on fertility varied by body mass index, said lead authorLauren Wise, a reproductive epidemiologist at Boston University.Body mass index (BMI) is a ratio of height to weight. Researchers in the United States and Denmark followed more than3,500 Danish women aged 18 to 40 who were trying to conceive overthe course of a year for the study, published in the journalFertility and Sterility. All reported being in a stable relationship with a male partner andwere not receiving any fertility treatments. Participants estimated the number of hours per week they had spentexercising in the past year, as well as the intensity of theirworkouts. Over the course of the study, nearly 70 percent of allwomen became pregnant. The researchers found that moderate exercise, such as walking,cycling or gardening, was associated with getting pregnant morequickly for all women, regardless of weight. Women who spent more than five hours per week doing moderateexercise were 18 percent more likely to become pregnant during anygiven menstrual cycle than women who performed moderate exercisefor less than an hour each week. However, normal-weight and very lean women who reported high levelsof vigorous exercise, such as running or aerobics, took longer toget pregnant. Those who exercised vigorously for more than fivehours each week had a 32 percent lower chance of becoming pregnantduring a given cycle than women who did not exercise vigorously atall. There was no association between vigorous exercise and the time ittook overweight or obese women -- those with a BMI of 25 or greater-- to become pregnant. While the study was large and well designed, there were someweaknesses, said Bonnie Dattel, an obstetrician at Eastern VirginiaMedical School in Norfolk, Virginia, in an email. Because the amount and intensity of exercise was self-reported,participants could have underestimated or overestimated theiractivity levels, she said. The results also don't mean exercise was responsible. Women whotook longer to conceive could also have modified their exercisepatterns, the researchers noted, making the relationship theopposite of what it appeared. In general, overweight and obese women have higher rates offertility issues and a variety of pregnancy complications, saidRichard Grazi, a reproductive specialist at Genesis Fertility inBrooklyn, New York, who was not part of the study. Fat is metabolically active -- it makes estrogens, he said. That extra estrogen can suppress other hormones responsible forovulation, which can lead to irregular menstrual cycles or even alack of menstruation. On the other hand, it's not clear why lean women who exercisevigorously may take longer to become pregnant. Having too little body fat may be a factor for some women, and it'sknown that competitive female athletes and very underweight womensometimes experience menstrual irregularities. We are high quality suppliers, our products such as MMC Flash Memory Card , China PS3 Slim Repair Parts for oversee buyer. To know more, please visits PS3 Repair Parts.
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