If you're looking to improve your health and fertility, you may assume that adding in exercise is one of the best actions to take. And while that is partially true, it's not the entire story. Even with exercise, too much of a good thing can be bad.
Some studies have shown that "too much" exercise may impede fertility. This doesn't only apply to women who exercise to the point of lowering their weight levels below the healthy range, but even to women who maintain a normal weight and continue to get regular menstrual cycles.

On the other hand, obesity can also lead to lower fertility. To combat obesity, a combination of diet and exercise is needed. Regular exercise can also lower stress, which is important when you're trying to cope with infertility.
So, how much exercise is too much? And how might too much exercise lead to infertility? To get more details on the connection between exercise and fertility, read this excerpt from UpToDate -- a trusted electronic reference used by many physicians and patients.
Then, read on for what all of this means for you.

"In some epidemiological studies, more than seven hours per week of aerobic exercise has been associated with ovulatory infertility. In women undergoing in vitro fertilization, four or more hours of strenuous exercise weekly over a period of years has been associated with poorer outcomes.
The effects of strenuous exercise on fertility could be related to (1) reduced progesterone production during the luteal phase of the menstrual cycle in ovulatory women (ie, luteal phase defect), (2) alterations in GnRH production, LH and FSH secretion, and estradiol production and metabolism, resulting in anovulation, or (3) changes in leptin levels. Other factors may include decreased body fat and changes in diet, such as an increase in fiber and a decrease in fat intake, in women who exercise strenuously.
From a population perspective, inadequate levels of exercise associated with obesity may be a more common cause of anovulation and subsequent infertility than exercise associated anovulation."

Infertility and Too Much Exercise

Too much exercise seems to impair ovulation, and there are a few theories on why this happens.
One possible result of too much exercise is a luteal phase defect. The luteal phase is the time period between ovulation and your expected period. This time period, also known as the "two week wait", is normally between 12 and 16 days.

A shorter luteal phase can interfere with getting pregnant.

Normally, progesterone levels remain high during this time, to allow a fertilized egg to attach itself to the uterine lining. Low levels of progesterone can interfere with a fertilized egg implanting, which leads to infertility.
Another potential reason for exercise-induced infertility is that the hormones responsible for regulating the female reproductive system -- GnRH, LH, FSH, and estradiol -- are changed in ways that interfere with ovulation.
Yet another potential cause for exercise-induced infertility is changes in leptin levels, which regulates appetite and metabolism. If your appetite is low, you may not eat enough, which can interfere with regular ovulation.
It's also possible that women who exercise more than 7 hours per week are more likely to restrict their diet. Not eating enough healthy fats, losing weight rapidly, or weighing below the recommended weight guidelines for your height can affect ovulation.

What If I'm Overweight?

While too much exercise is a problem for some women, there are more women with the opposite problem - not enough exercise, leading possibility to obesity.

Research shows that being overweight can also impair fertility.

The good news is that losing just a 10% of your current body weight has been shown to help fertility in women who are overweight. If your BMI is over 27, and you're trying to lose weight, you shouldn't shy away from exercise.
I'm Not Overweight, But I Like to Exercise. What Should I Do?
Exercise has many health benefits, and taking control of one's body can be empowering when trying to cope with infertility. With that being said, if you're trying to conceive, and your regular routine involves more than seven hours of intense exercise a week, you may want to cut back.
You may also want to consider replacing some of your more intense workouts with gentler forms of exercise. For example, instead of taking a high power aerobics class every day, you can replace some of your workouts with gentle yoga or leisurely walking. You'll still get to enjoy moving your body, but you won't be overtaxing your system.
More on boosting your fertility:

• 5 Thoughts That Keep You From Making Healthier, Happier Choices
• 5 Things Every Couple Should Know When Trying to Conceive
• 12 Take Action Plans for Getting Pregnant
• 5 Research-Backed Diets for Fertility

Want to learn more? See UpToDate's topic, "Optimizing natural fertility in couples planning pregnancy", for additional in-depth, current and unbiased medical information on infertility, including expert physician recommendations.
_{Source:
Olek, Michael J., Gibbons, William E. "Optimizing natural fertility in couples planning pregnancy." UpToDate. Accessed: September 2009.}

Infertility is recognized as a disease by the World Health Organization (WHO), American Society for Reproductive Medicine (ASRM) and the American College of Obstetricians and Gynecologists (ACOG).¹
Defined as the inability to conceive a child after one year of unprotected sex, infertility affects approximately 1 out of every 8 couples.²
Approximately 90 percent of male infertility is due to low sperm count or poor sperm quality, and the remaining 10 percent are the result of structural abnormalities, hormonal imbalances, genetic defects or other problems.³ Sperm abnormalities are critical to infertility and the health of a resulting pregnancy.
While much media attention has been placed on the necessity for women to care for their bodies prior to pregnancy, research has demonstrated the need for men to care for themselves in the same way to prevent birth defects, miscarriages and infertility.
Recent research now indicates that exercise may improve quality and quantity of sperm in men who were previously sedentary.⁴

Exercise May Improve Sperm Quality and Quantity

In a study completed in Iran, researchers evaluated the effect of four different levels of exercise on sperm quality in sedentary men. Of the couples struggling with infertility, 1 in 3 are the result of poor sperm quality.⁵
In this study, researchers from Urmia University evaluated the sperm of 261 healthy men over six months.
The participants were first determined to be otherwise healthy, between 25 and 40 years of age, and didn't regularly participate in an exercise program. They were then separated into the following four groups:⁶

• No exercise
• Three workouts a week of high-intensity training on a treadmill (HIIT)
• Three workouts a week of 30 minutes moderate-intensity continuous training on a treadmill (MICT)
• Three workouts a week of one-hour high-intensity continuous training on a treadmill (HICT)

The researchers used semen samples before, during and after the six-month exercise period to evaluate sperm motility, size, morphology (shape), count, semen volume and levels of inflammatory markers.
After 24 weeks, it was the MICT group who experienced the greatest improvements, although the HICT and HIIT groups also experienced improvement over the group who did not exercise.⁷
The MICT group had a greater than 8 percent rise in semen volume, over 12 percent improvement in sperm motility, 17 percent improvement in morphology and just over 21 percent more sperm cells on average.⁸
However, while the men enjoyed these improvements during the exercise program, the sperm count, concentration and morphology began dropping back to pre-workout levels within a week after stopping. Lead author of the study, Behzad Hajizadeh Maleki commented:⁹

"Our results show that doing exercise can be a simple, cheap and effective strategy for improving sperm quality in sedentary men.

However, it's important to acknowledge that the reason some men can't have children isn't just based on their sperm count. Male infertility problems can be complex and changing lifestyles might not solve these cases easily."

Moderate Exercise Increases Sperm Quality

The authors of the study theorized that although weight loss achieved by the men during the six months of the study was likely to have contributed to improving sperm quality, the men participating in MICT may have experienced the greatest impact as MICT reduces exposure to inflammatory agents and oxidative stress.¹⁰
Scientists have determined that exposure to electromagnetic fields, increased heat, poor nutrition, obesity, drugs, alcohol and bicycling may reduce sperm quality, and theorize that reducing these factors and improving health would then improve sperm health.
Another study of 31 men, 16 of whom were active (but did not bike) and 15 sedentary, underwent a shorter evaluation of sperm quality,¹¹ using the WHO's sperm quality parameters, including volume, count, motility and morphology.¹² 
Researchers found physically active men had a higher concentration of sperm, semen volume and a higher percentage of sperm with normal morphology.
In a previous study, these same authors found men who engaged in intense exercise instead experienced a reduction in sperm quality, but moderate exercise appeared to be linked to improve sperm quality.
Researchers from the most recent study also found that moderate activity, as described in their study parameters, yielded better results. The researchers commented:¹³

"The present study adds to this body of evidence and shows seminal markers of inflammation and oxidative stress improved significantly after 24 weeks of MICT, HICT or HIIT, and these changes correspond with favorable improvements in semen quality parameters and sperm DNA integrity.

These results further indicate that MICT was more beneficial in improving markers of male reproductive function, compared to HICT and HIIT.

These observations suggest that the intensity, duration and type of exercise training could be taken into consideration when investigating reproductive responses to exercise training in men."

Male Infertility Responsible for 30 Percent of Cases

Allan Pacey, Ph.D., and fellow of the Royal College of Obstetricians and Gynecologists (RCOG), is the British Fertility Society spokesman and professor of andrology at the University of Sheffield. He also commented on the research results and how they may affect fertility:¹⁴

"In this context, the study makes a good contribution to the knowledge base. It is a very well conducted and a strength is that it is a randomized controlled trial with extensive data collection.

Also, the study examines how exercise affects many of the parameters of male reproductive health, not just sperm quality. However, what is likely to be of most interest to men and their doctors are the results concerning sperm quality.

Importantly, these seem to show a statistical improvement to various degrees when the men embarked on their different exercise regimes compared to men who did no exercise at all. However, an important question is whether these statistical changes are enough to be of any clinical significance."

Male infertility contributes to 30 percent of all infertility cases.¹⁵ Of the four major causes of male infertility, between 40 percent and 50 percent of poor sperm quality is attributed to unknown factors. Male infertility is a complex condition encompassing both the health of the sperm and the mechanical functioning of the male reproductive system.¹⁶
Testing for male infertility includes a semen sample analysis, blood work, physical examination and an evaluation for any current infections or structural damage from past infections. Although frustrating to a couple trying to conceive a child, the risk of poor sperm quality extends beyond the inability to conceive.

Risks Associated With Poor Sperm Quality

Sperm motility, or the ability of sperm to move quickly and in a straight line, is one factor associated with sperm quality. Sperm that are sluggish or move poorly may be associated with DNA fragmentation, and the potential risk for passing genetic diseases.¹⁷ There is also some evidence that male infertility may be a risk factor for testicular cancer.¹⁸
Recurrent miscarriages may be attributed to chromosomal damage to either the egg or the sperm,¹⁹ and reduced sperm quality is associated with congenital deformities.²⁰ Chromosomal abnormalities in the sperm may contribute to poor sperm quality.
The risks of poor quality sperm also extend to the health of the man. Defects in sperm quality are linked to a variety of health concerns, including high blood pressure, diabetes, heart disease and skin and glandular disorders.²¹ Lead researcher Dr. Michael Eisenberg, assistant professor of urology and director of reproductive medicine and surgery at Stanford School of Medicine, commented that "[i]t may be that infertility is a marker for sickness overall."²²
A study evaluating more than 9,000 men with fertility issues found a correlation between defects in a man's sperm and the likelihood he suffers from other health conditions.²³ A previous study Eisenberg co-authored also indicated that men who experienced infertility issues had an overall higher rate of mortality in the following years. According to Eisenberg:²⁴

"A man's health is strongly correlated with his semen quality. Given the high incidence of infertility, we need to take a broader view. As we treat men's infertility, we should also assess their overall health. That visit to a fertility clinic represents a big opportunity to improve their treatment for other conditions, which we now suspect could actually help resolve the infertility they came in for in the first place."

Natural Sperm Boosting Options

While moderate exercise may help to improve sperm quality, there are other lifestyle choices that may help to enhance the improvements you experience. Infertility is a complex condition that is intimately incorporated the rest of your health. You may improve your sperm quality as you also improve your overall health and wellness.

Use Moderate-Intensity Continuous Exercise While Trying to Conceive Although HIIT is a healthy adjunct to an exercise program, the increased heat and oxidative stress on your body may produce time-limited changes to your sperm quality, and reduce your potential to conceive.

Reduce Exposure to Toxic Chemicals Unprecedented decline in fertility rates and semen quality in the past decade may be attributed to exposure to phthalates in your environment.25 Animal studies have demonstrated an association between phthalates and testicular toxicity26 and lowered sperm count.27 Other chemicals to avoid include paint fumes, pesticides, formaldehyde, organic solvents and dry cleaning chemicals.

Optimize Your Vitamin D Level Low vitamin D levels have been linked to infertility in both men and women. In men it is essential for the healthy development of the nucleus of the sperm cell, and helps maintain semen quality and sperm count. Vitamin D also increases levels of testosterone, which may boost libido. Aim to maintain a level of 40 to 60 nanograms per milliliter (ng/mL) year-round.

Maintain Your Weight Within Normal Limits Through a Whole Food Diet Obesity changes male hormone levels, which has a direct impact on sperm molecular composition and function.28 Use fresh foods as often as possible, ideally organically grown, to avoid pesticides. Seek out pastured, organic meat and dairy products, raw nuts, seeds and vegetables, and avoid dangerous trans fats found in many processed foods and vegetable oils.

Reduce or Eliminate Smoking, Alcohol and Drugs Each of these creates an added stress on your body with demonstrated reduction in fertility, sperm motility and quality.

Avoid the Heat Sperm require a specific temperature to remain active and viable. Avoid wearing tight underwear and tight pants, taking hot showers or baths and sitting in hot tubs. Keep your laptop off your lap as the increased heat from the machine also increases the temperature of your scrotum.29 Your body will naturally keep your sperm at the right temperature when you avoid circumstances that abnormally increase the temperature of your scrotum.

Avoid Placing Your Mobile Phone in Your Front Pants Pocket Research shows mobile phone radiation increases DNA fragmentation and reduces sperm motility.30 The Role of Vitamin D in Disease Prevention A growing body of evidence shows that vitamin D plays a crucial role in disease prevention and maintaining optimal health. There are about 30,000 genes in your body, and vitamin D affects nearly 3,000 of them, as well as vitamin D receptors located throughout your body. According to one large-scale study, optimal Vitamin D levels can slash your risk of cancer by as much as 60 percent. Keeping your levels optimized can help prevent at least 16 different types of cancer, including pancreatic, lung, ovarian, prostate and skin cancers. How Vitamin D Performance Testing Can Help Optimize Your Health Is it any wonder then that no matter what disease or condition is investigated, vitamin D appears to play a crucial role? This is why I am so excited about the D*Action Project by GrassrootsHealth. Dr. Robert Heaney is the research director of GrassrootsHealth and is part of the design of the D*action Project as well as analysis of the research findings. GrassrootsHealth shows how you can take action today on known science with a consensus of experts without waiting for institutional lethargy. It has shown how by combining the science of measurement (of vitamin D levels) with the personal choice of taking action and, the value of education about individual measures that one can truly be in charge of their own health. In order to spread this health movement to more communities, the project needs your involvement. To participate, simply purchase the D*Action Measurement Kit and follow the registration instructions included. (Please note that 100 percent of the proceeds from the kits go to fund the research project. I do not charge a single dime as a distributor of the test kits.) As a participant, you agree to test your vitamin D levels twice a year during a five-year study, and share your health status to demonstrate the public health impact of this nutrient. There is a $65 fee every six months for your sponsorship of this research project, which includes a test kit to be used at home, and electronic reports on your ongoing progress. You will get a follow up email every six months reminding you "it's time for your next test and health survey."