Health researchers believe that while much exercise can deter normal weight women from getting pregnant.
However, it seems to have little effect on heavy weight women.
While exercise might be great for women trying to get pregnant, too much exercise might reduce the chances of getting pregnant in normal weight women.
It was discovered by some U.S. and Danish researchers who studied the link between physical activity and fertility using Danish women as case study.
The result of the research led them to posit that being fat, or even obese, does not hinder the tendency of getting pregnant among heavy women who do vigorous exercises.
These exercises include running, fast cycling, and aerobics. Find more tips and exercises on http://www.webmd.com/.
Normal weight women, however, were found to have less chances of getting pregnant if they engage in vigorous exercises.
Lauren Wise, an associate professor of epidemiology and study author, points out that higher rates of fertility were observed in heavy women who were engaged in vigorous exercises.
But the reverse seems to be the case for women with normal body weight.
Wise related that the importance of the research is to let heavy weight women know that their chances of becoming pregnant can be increased by engaging in vigorous exercises.
She also advised that normal weight women who wish to increase their fertility rate should engage in less difficult exercises such as walking and gardening rather than running or weight lifting.
It has also been observed among competitive female athletes that intense exercise disturbs the regular menstrual cycle.
Intense exercise among normal weight women can deter ovulation or cause the absence of menstrual cycle.
And it can also prevent the sperm from reaching a fertilized egg attached to the wall of the uterus.
In the course of the research, the researchers distributed questionnaires to 3,628 women within the age bracket of 18 to 40 years.
This distribution was done over the internet.
As a rule, the women should not be undergoing any fertility treatment.
And they have to be in stable relationships with male partners and have plans to get pregnant.
Information on height, reproductive and medical history, body weight, lifestyle, and behavioral details were collected first from https://www.nih.gov/.
Then questionnaires were sent via email to them for every two months for a period of 12 months or till the woman conceives.
The first question asked these women was the average number of hours they exercised per week.
Also, they were also to answer questions on the kind of physical exercises they did, if it was simple or a difficult activity.
Exercises such as running, fast cycling, gymnastics, and swimming were considered strenuous.
But brisk walking, leisurely cycling, gardening, and golfing were considered to be less strenuous exercises.
Participants were classified based on the level of exercise performed and results evaluated according to body mass index (BMI, a ratio of weight to height).
Any BMI over 25 is considered overweight or obese.\
It was discovered that less vigorous physical activity can be linked to increased fertility or ability to get pregnant quickly.
The researchers also discovered that the reverse is the case for women who have normal weight (a BMI below 25).
Normal weight women who engage in strenuous physical activity have reduced chances of becoming pregnant.
But there was no link found between obese women who engaged in strenuous physical activity and the time it took them to become pregnant.
These findings were published in March 15 in the Journal of Fertility and Sterility, even though the study did not prove a cause-and effect-relationship.
Wise observed that other research posited that being obese might lead to reduced chances of becoming pregnant compared to the fertility rate among normal weight women.
She also pointed out that obesity has often been linked with the instability of menstrual cycles.
Wise proposes something different from her predecessors who have studied the relationship between pregnancy and women weight.
She posits that obese women should engage in more vigorous exercises to decrease harmful effects of obesity and increase chances of becoming pregnant.
Why increased physical activity in obese women might lead to increase fertility rate is unclear since the researchers did not dig into this aspect.
Dr. Dimitrios Mastrogiannis, director of the Division of Maternal-Fetal Medicine and an associate professor of obstetrics, gynecology and reproductive sciences at Temple University School of Medicine in Philadelphia, pointed out that:
“Obesity is a different ballgame. Different hormones are playing around in obesity—fatty tissue produces more female hormones, more estrogens. Other hormones are transformed into female hormones in the adipose tissue.”
He said that the research does not indicate that one should become obese to increase the chances of becoming pregnant.
Neither does total disengagement from physical activity increase probability of becoming pregnant.
Mastrogiannis noted that exercise is good since it reduces the chances of having such diseases as cancers, cardiovascular disease, diabetes etc.
And physical exercise can also be linked to better chances of becoming pregnant, less pain, easier labor, and fewer induced births.
The study concludes that normal weight women who wish to get pregnant should stick to moderate aerobic exercise.
The researchers recommended that normal weight women should engage in moderate exercises such as walking for; at least; 30 minutes in a day.
Mastrogiannis pointed out that: “If they engage in very vigorous exercise (such as running, fast cycling, gymnastics or swimming) for more than five hours a week, it makes them less fertile.”
So, it is good and beneficial for heavy and obese women to engage in vigorous exercises as it does not reduce their chances of becoming pregnant.
But normal size women need do only mild exercises if they hope to increase their chances of becoming pregnant.