Your biology is programmed to heighten your stress response in the second half of your cycle compared with the first half, according to a 2017 study in the journal Physiology & Behavior. Earlier research from a 2013 issue of Psychoneuroendocrinology found that females release a greater amount of the stress hormone cortisol during the second half of the cycle compared with the first half. It’s likely this heightened response is nature’s way of helping you protect a fertilized egg in the event you’re pregnant.
