Exercise and Fertility

There is a clear relationship between exercise and the menstrual cycle. Athletes during training, for example, miss periods or have irregular cycles with luteal phase abnormalities. Vigorous exercise is a strain on the body and, when intense enough, can cause the release of excess stress hormones (adrenaline and cortisol). For women with a low or normal BMI, vigorous exercise can lead to excess cortisol (remember, you need cortisol—it’s not all bad but it has to be balanced especially when you are making a human). There are several large randomized controlled studies (link to article) that show for women with a low to normal BMI vigorous exercise is associated with a longer time to conceive. A large prospective Danish study of over 3,000 women (link to article) also showed comparable results.

It’s also important to remember that cortisol follows the body’s circadian rhythm (higher in the morning and lower in the evening) so if you’re going to do a more intense work-out, doing it in the morning may help limit the stress on your body. This way your exercise matches your natural cortisol spike.

You definitely don’t need to (and shouldn’t) stop exercising. Exercise is good for your fertility, overall, and releases good hormones too (endorphins). The key is to not add more stress to the body. If you’ve always done Crossfit or Solidcore, keep doing it. If you’re struggling with infertility, tone it down to 75-80% of your maximum effort so that you don’t over-activate cortisol and create an imbalance. It’s also a good idea to mix in some forms of physical activity that work with a mind-body connection such as yoga. It’s not one size fits all—part of your journey is figuring out the balance that is right for your body. It’s also important to remember that certain types of exercise/intensity levels promote your fertility depending on what’s going on with your body, so make sure you’re doing the right kind and right intensity of workout.