So you want to have a baby? I bet you have been thinking about eating a healthier diet and beginning an exercise routine. Before you begin a new workout plan or ramp up your current one, consider this: extreme exercise has been shown to be bad for fertility and may actually inhibit conception.
Studies have shown that high-intensity workouts can alter hormonal balance, disrupt ovulation, and alter the entire menstrual cycle. Studies also show that leading a sedentary lifestyle can be detrimental to fertility, so truly it is all about moderation.
Regular exercise is important for fertility, but it needs to be low-impact, moderate, and done on a consistent basis. How can you tell if your exercise routine falls into that category though? Let’s take a look at the research to help us decide which activities are best for fertility…
Research: Extreme Exercise Lowers Fertility
Long-term Survey Reveals Lowered Fertility In Women Who Engage in Regular Strenuous Exercise
A Norwegian study headed by Sigridur Lara Gudmundsdottir, a PhD candidate in NTNU’s Human Movement Science Programme, published in the Journal of Human Reproduction, involving nearly 3000 women, sought to discover if extreme or low levels of physical activity affected fertility. All women were of good health and of childbearing age. The study followed these women and regularly questioned them about their level of physical activity between 1984 and 1986. The women were then asked about their pregnancies 10 years later, between the years of 1995 and 1997.
“Among these women, we found two groups who experienced an increased risk of infertility. There were those who trained almost every day and there were those who trained until they were exhausted. Those who did both had the highest risk of infertility…” “We believe it is likely that physical activity at a very high or very low level has a negative effect on fertility, while moderate activity is beneficial,” said Dr Gudmundsdottir.
Good news from the results of these surveys is that many women who trained the hardest at one time went on to have children by lowering their physical activity to a moderate level. Infertility due to high intensity exercise may be able to be reversed by a reduction in physical activity and increase in body fat.
Hormonal Disruption Due to Extreme Exercise
Researchers at the University of North Carolina found that high-intensity, strenuous, and prolonged exercise increases cortisol levels, while lowering thyroid hormones. Thyroid hormones stimulate your metabolism and the desired outcome of exercise is definitely not to lower your metabolism.
The study showed that even after 24 hours of recovery post-exercise, cortisol levels remained elevated and thyroid hormones suppressed. Both high cortisol levels and low thyroid hormones have been linked to poor adrenal health which also in-turn directly impacts thyroid function and how the body handles stress long-term, all of which can negatively impact overall hormonal balance and fertility.
Low Levels of Body Fat Decrease Fertility
A study published in the Journal of Clinical Endocrinology & Metabolism in 1993 used magnetic resonance imaging (MRI) scans of both external and internal body fat deposits of extremely athletic women, compared to non-athletic women. The MRI was used to measure fat deposits in 17 different sites in the body, including that of the thoracic vertebrae compared to fat of the upper thigh. Urinary analysis of estrogen was also tracked.
Results of this study shows that extremely athletic women do in fact have lower levels of body fat overall, which may directly decrease fertility. Extremely athletic women, who had menstrual cycle and ovulatory irregularities, had significantly lower levels of both subcutaneous and internal body fat at all sites in the body, compared to the controls. Extreme athletes that had regular ovulation had lower levels of internal body fat at vertebrae lumbar 4, sacral 1, and sacral 4, but had adequate levels of subcutaneous fat.
Levels of estradiol (this estrogen is the most potent and abundant form of estrogen; its main action is the involvement in development of secondary sex characteristics and the menstrual cycle) was significantly related to total fat at all sites in the body. The extreme athletes were shown to have significantly lower estradiol than those of the controls.
Exercise That Is Good For Fertility
Now that we have moved through all of the research, let’s get to activities that are beneficial for fertility because never exercising can be just as bad. Regular, moderate exercise has been shown to strengthen muscles, build stamina, increase flexibility, increase circulation, reduce stress, prevent depression and anxiety, while promoting regular detoxification of excess hormones and toxins in the body. All of these benefits make regular, moderate exercise essential for healthy pregnancy preparation.
Women who are trying to conceive should exercise regularly at a moderate level for 30 minutes a day, 3 times a week, with 2, 30-minute strength training sessions. Some days could include 1-2 sessions of yoga for an hour. Fertility Yoga has been shown to help support healthy fertility. We do not suggest doing any yoga poses after ovulation that compress the abdomen if you are trying to conceive.
Exercise we find best for women trying to conceive:
- Brisk walking, 5 times a week, for 30 minutes to 1 hour
- 2-3 1-hour sessions of yoga
- Nia, 2-3 times a week
- Zumba, 2-3 times a week
- Aerobics, 2-3 times a week
- Leisurely bike riding
- Light jogging
Exercise to avoid while trying to conceive:
- Bikram yoga (hot yoga, raised body temperature)
- Core strength training after ovulation, including core Pilates training
- Exercise 7 days a week for more than 45 minutes to 1 hour
- Running for many miles each day
- Extreme “boot-camp” training series
- Exercise over an hour long
- Any type of regular, strenuous training for sports (running, gymnastics, ballet, etc.)
What about exercise after IUI or IVF?
For women going through medical fertility treatments, doctors often suggest that their patients avoid exercise. We definitely agree that extreme exercise and fitness training should be avoided, so should the activities listed in Exercises to Avoid (just above). We do feel that walking daily and doing some light yoga would be beneficial to the health and stress levels for women going through medical fertility treatments.
- Hard workouts can temporarily reduce a woman’s fertility. (2010). Retrieved from: https://www.ntnu.edu/news/hard-workouts-reduced-fertility
- R E Frisch, R C Snow, L A Johnson, B Gerard, R Barbieri, and B Rosen. (Aug. 1, 1993) Magnetic resonance imaging of overall and regional body fat, estrogen metabolism, and ovulation of athletes compared to controls. The Journal of Clinical Endocrinology & Metabolism. Vol. 77 no. 2471-477. DOI: http://dx.doi.org/10.1210/jcem.77.2.8345054. Retrieved from: https://academic.oup.com/jcem/article-abstract/77/2/471/2650471?redirectedFrom=fulltext
- Anthony C. Hackney & Claudio Battaglini. (June 2007). The Overtraining Syndrome: Neuro-endocrine imbalances in athletes. Applied Physiology Laboratory, Department of Exercise & Sport Science, University of North Carolina. Retrieved from: http://www.redalyc.org/html/930/93001204/