Can Too Much Exercise Decrease Your Fertility?

How Jogging, Yoga, Weight Training, and Walking Affect Fertility

Caucasian couple running together on path
Exercising with your partner is a great way to boost your overall health... but don't over do it. Blend Images/John Fedele/Brand X Pictures/Getty Images

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 in some situations.

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.

How much exercise is too much? And how might too much exercise decrease your fertility?

What’s Too Much, What’s Okay, and Why

The research on exercise and fertility has been mixed. Some studies have found that “too much” exercise can impede fertility, while others have not found that association. There are also studies that have found that regular exercise can improve fertility.

Studying the effects of exercise and fertility is complicated, since you can’t exactly put people in a lab for years to observe their exercise habits. All the studies rely on self-reports from patients. Plus, it’s difficult to tease out other factors that may impact fertility. For example, someone who exercises frequently might have different eating habits from someone who doesn’t. What you eat can also impact fertility.

The most recent research has come to this current conclusion: moderate exercise is beneficial to all women and may even improve fertility. Vigorous exercise can improve fertility in women who are obese but may negatively impact fertility in women of normal weight.

What is too much exercise? Studies have come to different conclusions, but here are a few:

  • Strenuous exercise of four or more hours per week may reduce IVF success rates
  • Aerobic exercise for seven or more hours per week may increase the risk of ovulation problems
  • Vigorous exercise may improve fertility in women who are obese
  • Vigorous exercise may decrease fertility in women who are at their normal weight
  • Moderate exercise (for more than hour but less than five hours per week) was found to improve fertility in all women

Strenuous or vigorous exercise include activities like...

  • Biking
  • Jogging
  • Swimming
  • Racquetball
  • Aerobic exercise
  • Weight training

Moderate exercise includes activities like...

  • Walking
  • Household activity exercises (like gardening)
  • Yoga

When considering what to limit or cutback on, exercise in the vigorous category is what should be limited to less than four hours per week. You don’t need to limit moderate exercises.

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 four 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 yoga or leisurely walking. You'll still get to enjoy moving your body, but you won't be overtaxing your system.

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 of obesity. Research shows that being overweight can also impair fertility.

More to the point, studies looking at obesity, exercise, and fertility together have found that for women who need to lose weight, vigorous exercise can actually improve their odds of getting pregnant. If you’re overweight, you probably don’t need to worry that strenuous exercise will harm your fertility.

You should, of course, always talk to your doctor if you’re concerned.

Also, remember that diet is just as important—and maybe even more important—than exercise, when you’re trying to lose weight. Reducing junk food and increasing healthy food options, like whole grains, healthy fats, lean proteins, and lots of vegetables, has been found to help with weight loss and improve fertility.

Something else to keep in mind—losing just 10 percent of your current body weight can boost your health and fertility if you are currently obese. In other words, you don’t necessarily have to get down to your “healthy, normal” BMI for your height in order to see fertility improvements. (BMI is a measurement used to evaluate someone’s weight based on his or her height.)

Here’s an example. Let’s say a woman is 5’ 4” and weighs 174 pounds. This would give her a current BMI of 30 and place her in the category of being obese. To be at her healthy, normal weight on the BMI chart, she’d need to weigh 144 pounds. That would mean losing 30 pounds, which is a lot of weight.

However, the research says that if she loses just 10 percent—which would be about 17 pounds in this example—her fertility would see improvements. This is true even though she would technically still be considered overweight (at 157 lbs.)  

Why Might Too Much Exercise Decrease Fertility?

Too much exercise seems to impair ovulation in women of normal weight, 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 changed 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 seven 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.

A Word From Verywell

One to five hours of week of moderate exercise like walking, yoga, or household activities (like gardening or cleaning) can improve fertility in all women. Vigorous exercise can improve fertility in obese women, but it may slightly reduce fertility in women of a healthy weight. This doesn’t mean you can’t exercise! Only that you should try to limit strenuous activities—like jogging or aerobics—to less than four hours per week if you don’t have weight to lose.

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