Andrew Huberman· PhD
Now that said, there are a number of different ways that women will track their ovulation. One is the temperature method. So they'll actually measure intravaginal temperature. They're looking for changes in temperature that are consistent around the time of ovulation. We're going to have an expert guest on, an OB/GYN, who can tell us a lot more about the details and nuances of the temperature method. You'll see a lot of information about this online, but there's a lot of misunderstanding about it, as well. Other women will use apps that take into account either the temperature information if they're acquiring temperature information-- that'll be entered into the app-- as well as marking the onset of menstruation, the onset of bleeding, therefore, the start of the ovulatory cycle, because, of course, as we mentioned earlier, that marks day one of their cycle. And then, again and again, you can see how regularity of cycle duration or relative regularity of cycle duration really favors this whole process of being able to predict when one ovulates. And fortunately, if the goal is fertilization, there are some margins for error that are introduced by the fact that the sperm can survive within the female reproductive tract for some period of days, thereby reducing the need for absolute certainty about the time of ovulation and so on. In fact, it's pretty well known that around the time of ovulation a couple of things happen. Earlier, we talked about one thing, which is there's an increase in libido just prior to ovulation. This relates to, in part, an increase in some of the androgens, things like DHEA, but also testosterone and some related androgens that can increase libido both in males and females and changes to the reproductive pathway, the female in particular, a change in the pH-- that is, the relative acidity versus basic nature of the mucosal lining near the cervix and also vaginal secretions, such that, around the time of ovulation, the entire milieu of the vagina and the cervix and the locations in which fertilization can occur and certainly in which the sperm are swimming towards the opportunity for fertilization is shifted to support sperm motility and health. In other words, one of the best environments for sperm to survive is going to be within the female reproductive tract itself. And as long as we're talking about vaginal secretions and mucus, it's important to point out that a number of commercially available lubricants can actually be detrimental for sperm health, even if they don't contain spermicide.