Of all the health problems the general population faces, exercising too much is nowhere near the top of the list. It's well-documented that a sedentary lifestyle and its effects -- an overweight and obese society -- is literally a growing concern. But an overabundance of exercise does have the potential to impact fertility in both men and women.
A healthy and hardy sperm count increases a man's odds of getting his partner pregnant. But any sport, such as cycling, that presses the testicles against the body may cause a decrease in the number of sperm available to vie for fertilization of the female egg. The temperature of the region simply becomes too hot to support optimal sperm counts. The use of steroids, which are both unhealthy and illegal, can also threaten fertility [source: Parenting.com].
In women, fertility issues tend to be more complex. Hormone levels can be affected by exercise and underweight females. Excessive heat -- which can be produced in a sauna or during intense workouts -- is associated with miscarriage. It has also been cited as a cause of birth defects [source: Parenting.com]. Exercise-induced endorphins boost prolactin levels that can make a pregnancy less likely to occur. Women who are extremely active are also more prone to have inconsistent menstrual cycles and, in some cases, they won't ovulate if they are underweight even when a menstrual cycle occurs [source: Advanced Reproductive Care].
To fully understand the issue of exercise and its connection with fertility, it's important to define what too much exercise is and what's considered an unhealthy body weight. Click ahead to learn more about body mass and the impact exercise can have on a person's odds of becoming pregnant.
How Body Mass and Physical Activity Affect Fertility
You don't have to be a physician or a prominent researcher to know that no one person is the same. So, to say a particular weight is healthy is to oversimplify the matter. Height, body composition and even sex have to be factored into the equation.
The Body Mass Index can give you a broad idea of what's considered a normal weight for someone of your height and sex. But don't stop there. In addition, you'll want to figure your body composition. A woman whose body mass measurement is less than 85 percent of a healthy weight range on the BMI scale may have a harder time becoming pregnant [source: Chang].
Less than ideal estrogen levels are connected with being underweight. Anovulation -- the inability to ovulate -- is also associated with low body weight [source: Attain Fertility]. Some sports medical doctors suggest that a woman's body simply determines that its environment can't provide sufficient nutrition to sustain a new life [source: Heckel].
The good news is that a modest amount of weight gain appears to restore fertility [source: Heckel]. It's important to remember, however, that the weight gain recommended is generally small. Overweight and obese people also risk infertility and they face a higher incidence of miscarriage [source: Attain Fertility].
The next issue to consider is the definition of too much exercise. Click ahead to learn what is and isn't a healthy activity level for a parent-to-be.
The Best Level of Exercise for Preconception and Pregnancy
Research has shown that too much exercise can cause infertility due to low body weight and hormonal changes. Exhaustion caused by intense and regular exercise may render a body unable to conceive or sustain a pregnancy. But what is too much exercise? It can vary from person to person.
While one person may exercise three times a week for 60 minutes and be incapable of getting pregnant, another could work out 21 hours a week and have a healthy baby [source: Arc Fertility]. Research, however, has established some basic guidelines. The Mayo Clinic encourages women seeking to become pregnant to avoid working out more than seven hours a week [source: Heckel]. Outside of time parameters, studies have shown that working out every day -- or to the point of high fatigue -- is associated with an inability to become pregnant [source: Guy].
Your mother may have told you "all things in moderation." That advice rings true if you want to become a mother or father, too. Exercise and good nutrition are important components of a healthy pregnancy. Just don't exceed the time guidelines, become underweight, overheat or exercise to the point of exhaustion. Otherwise, you should be able to embrace your role as a healthy, active parent.
- Attain Fertility Health Desk. "What's your ideal fertility weight?" Attain Fertility. (July 4, 2012) http://attainfertility.com/article/ideal-fertility-weight
- Chang, Wendy M.D. "Body Fat, Exercise and Fertility." Southern California Reproductive Center. (July 4, 2012) http://www.arcfertility.com/body-fat-exercise-and-fertility/
- Guy, Sarah. "Too Much Exercise May Be Bad for Fertility." Bio News. Nov. 22, 2009. (July 4, 2012) http://www.bionews.org.uk/page_51170.asp
- Heckel, Aimee. "Some Ultra-athletes See An Impact On Their Fertility." Daily Camera. Nov. 8, 2011. (July 4, 2012) http://www.dailycamera.com/lifestyles/ci_19283560
- Mendez, Elizabeth. "More Americans Now Normal Weight Than Overweight." Oct. 7, 2011. (July 4, 2012) http://www.gallup.com/poll/149975/americans-normal-weight-overweight.aspx
- Parents.com. "Can too much exercise affect fertility?" (July 4, 2012) http://www.parents.com/advice/pregnancy-birth/getting-pregnant/can-too-much-exercise-affect-fertility/
- Reproductive Partners. "Can too much exercise impair fertility?" (July 4, 2012) http://www.reproductivepartners.com/blog/968/can-too-much-exercise-impair-fertility.html