Understand Female Desire, Attraction, and Partner Choice | Sarah Hill

Introducing Sarah Hill & The Period Brain

When you look at the differences between the sort of ideal male face, when it's sort of created digitally using a computer program that's used to test these things, what they find is that when women are using hormonal birth control, they create a more feminized male face created by naturally cycling women. I think women have been led to believe that the only way forward to promote egalitarian society is to deny our biological differences for men 100%. And so most of the insights that we have about what it looks like to have a heart attack or what good nutrition looks like or what sleep requirements look like, a lot of that's based on research that was conducted in men. >> I'm pregnant. >> Beginning to understand what your brain and your body are actually trying to do as you move between different cycle phases. What are we 50% of the population is female. Even if you're a man who's like trying desperately to avoid women, you're probably going to have to interact with us at some point in your life. Sarah Hill, welcome back to my podcast. >> So glad to be here. Thank you for having me. >> This is exciting.

So, you have a new book, The Period Brain, which we are going to be talking about. But before we get started, can you give people a brief introduction to who you are and what you do? >> Sure. So, I'm Dr. Sarah Hill. I'm an evolutionary psychologist and I'm a researcher and professor. And I've spent most of my career studying women's brains and women's psychology and more recently sort of specializing within that area looking at women's hormones and the way that women's hormones and hormonal changes influence the way that women think, feel, and experience the world. And so I do that looking at women's naturally occurring hormones.

Um, and then also looking at the impact of hormonal birth control on women's psychology, which is what we talked about last time. >> Yes. Which is fascinating. And that's also what you taught a course for at Peterson Academy. >> Yeah. So, I just got done recording a really fascinating like I had so much fun putting the lectures together. Um, it is an intro to evolutionary approaches to human behavior and then using that as a foundation to understand sex differentiation. And so understanding the biological differences between men and women and then talking about, you know, knowing everything that we know about women and men and about women's psychology and about men's and women's hormones and the way that those differ and the way that those influence um men and women and the way they experience the world, then what does that mean when we give women hormonal birth control, which flatlines their hormones and and replaces them with synthetics? And so it's really a cool course because it walks through all of these different areas walking through, you know, evolutionary approaches to human behavior, understanding sex differentiation, understanding neuroendocrinology, so understanding how our hormones create sex differentiation, and then what happens with the pill.

That was perfect. I'm so excited for that course to come out. After we talked on the podcast last year and after I found out what birth control like actually does to women, I was like, "This is information everybody should know, including men >> who are going to be dating these women cuz like everybody needs to know this." And anyway, you're doing a fantastic job of spreading that around. Um, we had like one of the clips from the old podcast went off on TikTok >> and I think it was about mate selection and the birth control. >> Yes. Yeah.

Choosing a Partner on the Pill

So, you know, and all of that is grounded in research on women, the effects of women's indogenous or internally produced hormones and the way that that impacts partner choice. And there's a whole lot of research that finds that, you know, when estrogen is rising and high across the cycle, so during times when conception is possible, that this increases women's attunement to cues related to fa facial masculinity. And the idea is that when conception is possible across the cycle that our brains are really kind of dialed in to qualities related to good genes. And um you know it was only later that researchers asked well what happens when you quash women's estrogen production. You know does that mean that it leads to less of a preference for masculineized male faces? And the research suggests that yes it does. And when you look at the differences between the a sort of ideal male face when it's sort of created digitally using a computer program that's used to test these things.

What they find is that when women are using hormonal birth control, they create a more feminized male face than what's created by naturally cycling women, which is really fascinating. >> Yeah. >> It's like fascinating and terrifying. >> Children are often the best philosophers. They're always asking why, how am I supposed to live my life? What is good, right, correct, proper, best? Beauty used to be considered sacred. What have we replaced this ancient notion of beauty with? Do you believe that truths are absolute or are they all relative? >> The answers are different in the leading intellectuals. What is it that sets apart these thinkers?

Plato and Aristotle, Chrisus, Dioynes and Marcus Aurelius, Saurin Kerkugard, Ruth Benedict, Philip. Nature is daunting psychologically. He's like a motivational speaker. He's practical in a way that philosophers seldom are. >> Philosophy begins in wonder. I hope that you can take it with you in a further philosophical quest and work out your own answers to the big questions. What happens to women say who met somebody on the pill, got married, and now they're off the pill and they want to have kids. Have are there any stats around like is it hard on relationships or does it sometimes not matter? >> Yeah.

So, you know, it's really interesting because there there's been a couple of studies now that have been done following up on women who chose their partners when they're on the pill and seeing what happens later. And we actually just did one that we're um about to submit for publication. So, I'll tell you a little bit about what's in the literature and then I'll give you like um fresh off the, you know, fresh off the scientific um press um the results of our study, but some some of the original studies have found that yes, it can lead to differences in attraction. So, if you choose your partner on the pill and then you go off of it, there was this really lovely longitudinal study that was done that followed married couples over time. And during that time, of course, some of the women who chose their marriage partner when they were on the pill went off of it. And what they found was that it led to changes in attraction. But whether it became that but whether it became that women were more attracted to their partner or less attract attracted to their partner depended on how attractive their partner was.

And what they what they found was that women who were married to somebody who was really attractive that like received objective ratings of attractiveness by outside people that women when they went off the pill it was like the blinders came off and they were like, "Oh my gosh, you beautiful man." You know, and they were more attracted to their partner and and had more um relationship satisfaction as a result. But then women who were married to men who were less attractive, rated less attractive by objective ratings, they found that these women were less attracted to their partner and it also went and decreased their marital satisfaction. >> Wow. Yeah. So, which is, you know, really scary to think about and Yeah. And so, so we followed up on that and we did a study.

Studies on Partner Selection and Relationship Satisfaction

We partnered with Natural Cycles, the tracking app. Oh, yeah. And so we were able to look at um we conducted a survey on their users and we were also able to look at some user data and we found some really interesting patterns and that's cool. >> Yeah. So I'd love to tell you about these. So the first Yeah. So the first thing that we found that that I thought was really cool was um and and just to tell you a little bit about the sample, these are natural cycles users. So these are these women are off of hormonal birth control, but we got a sample of women who were all on it before, right?

So they they had to have been on it sometime in the past. And we did that just because we wanted to make sure that any differences that we found between women who chose their partners on the pill or chose their partners off the pill wasn't just because we're looking at differences between people who are willing to use birth control and not. Does that make sense? Yes. >> All right. So these are all former hormonal birth control users about half of whom chose their partners that they're with when they were on the pill and about half of them had chosen them when they're off the pill. and now they're naturally cycling. And so one of the things that we looked at was just frequency of logged sexual behavior over the course of cycles. And what we found was that the women who chose their partners when they were off the pill were having more sex with their partners than women who chose their partners on the pill.

Which again suggests that if you choose your partner when you're naturally naturally cycling and your hormones are able to detect these, you know, differences in qualities that lead to just physical attraction and just sexual desire, >> right? That that this must that this might be orienting them toward choosing those partners. They choose them, they're more sexually attracted to them and they have more sex across the cycle. So that was one thing that we found that we thought was really interesting. And there were also differences in just levels of physical attraction to the partners that we found between women who chose their partners when they were on the pill and off the pill. So women who chose their partners when they were off the pill, right? So, women who chose their partners when they were naturally cycling reported being more sexually attracted to their partners than women who chose their partners when they were on the pill, which again suggests that when you choose your partner, when you're naturally cycling and your hormones are playing a role in sort of helping direct your partner choice, that it's going to lead you toward those people that you're most sexually attracted to.

Oh my gosh. Because that's one of the things that estrogen does is like estrogen primes our brain to be able to like sort of tell the difference between really small differences between individual men just in terms of, you know, qualities that influence our sexual attraction and sexual desire. And when you're on the pill, sexual desire is just, you know, it's like the the fire is put out in a lot of ways. And so it's like women aren't prioritizing cues related to sexual attraction when they're on the pill because they have their sexual desire is dampened. And so when women are naturally cycling and are able to experience the magnitude of sexual desire that women are capable of when estrogen levels are high, then they prioritize those qualities. They prioritize qualities related to sexual attraction and sexual desire. And um and it seems like those are the partners that they're choosing is that they're choosing partners that they're sexually attracted to.

And when we look at our data and show that we have these higher levels of sexual attraction um in those relationships where the woman chose her partner when she's naturally cycling compared to those when a woman chose her partner when they're on the pill is pretty provocative. >> That's crazy. >> Yeah, it's crazy. >> I wonder Oh my gosh. >> Well, so so now I want to say the thing that's going to like make people because if everybody is like especially if they chose their partners on the pill, I want to I want Here's my caveat.

Caveat for How The Pill Affects Partner Selection

So like don't fall off the couch with anxiety because the other thing that we did is we looked at changes in sexual desire from the time that they went off the pill compared to now. So like to what extent do you feel more attracted to your partner, similarly attracted to your partner or less attracted to your partner? And here's the good news. About 40ish% of women reported that they have no changes in sexual attraction to their partner. right? That that they may have just chosen somebody that they may, you know, they they might like other things about them or they might have been really sexually attracted to them and that just has remained unchanged. So about 40% of women experience no changes. So that's good news. >> About 20ish% 20 to 30%, I don't remember the numbers of women report feeling more attracted to their partner.

So again, this deal where you like the blinders come off and all of a sudden your sexual desire is like doing its usual thing and and you're picking up on these fine-tuned differences between men in terms of qualities like genetic compatibility and testosterone levels and these other things that female brains find sexy >> and um and all of a sudden the blinders are off and they're like, "Yes, I'm so glad I have you in my life." Right? And they're they feel even more attracted to their partner. But about I think it was 22 to 25% of women experience the opposite. And so that that that is the effect where you have women experiencing the decrease in sexual attraction to their partner as a result of going off the pill. And this is where there's a mismatch where the women when they chose their partners when they were on the pill and their sexual desire is dampened and their ability to tell the difference between men is is dampened and then they go off of the pill and all of a sudden that stuff comes roaring back and they don't find that their partner is the one they're most attracted to. That's where you get into trouble.

And so it is a you know it is a relatively small percent of women when we consider the totality of all of the women involved but it's enough where if I was a woman who was like in the process of choosing a marriage partner like I wouldn't be on the pill when I was choosing that marriage partner just as an insurance policy because what would the you know if especially if you don't need it what would the point be? >> Also that 40% of people where it's like oh there was no difference. >> Yeah but then do you know that you chose right in the first place? Like maybe nothing's changed, but would it have led to different outcomes? >> Oh my gosh.

Does Birth Control Affect Society at Scale?

Do you think this has had an impact >> like >> across society in any way like genetically? It seems so risky to like mess with >> Right. Right. >> evolution's mate choice and then just be like tweak it a little bit. >> Right. Right. Yeah. You know, it's really interesting because I've wondered that myself. And the thing I've wondered about in particular is, you know, there's some research that finds that women who are naturally cycling prefer the scent of men who are genetically compatible to themselves and who have different immune genes than themselves.

And so, I've always wondered about whether or not some of the differences that we see in um you know, the changing fertility rate because we're seeing a greater number of couples struggle with infertility. And part of the reason is that women are just delaying childbearing until later. And that of course is going to create larger problems with infertility because when you're older as a female, it's less probable to get pregnant easily. Um, but I do wonder whether there's a portion of that that isn't accounted for the fact that women are choosing partners when they're on the pill, which is sort of dampening their sensitivity to cues of genetic compatibility. And whether this might be leading to some of the unexplained infertility that we see um because they're unable to get pregnant potentially because they're, you know, there's not they're not Yeah. Which which I think is really interesting. And there was one study that was done that was actually consistent with this where there was a study that looked at whether women chose their partners on or off of hormonal birth control.

And then they looked at the number of doctor visits that their children had. Um, and this was only one study, but they did find that the women who chose their partners on the pill that their children had to visit the doctor's office more frequently than did those who um chose their partners when they were off the pill. And you know, and this is just like one data point. And obviously, we we need a lot more research to know better than that. But one of the things that I've been working on being able to test is working with another one of these cycle tracking apps because I've got research relationships with a couple of them now and being able to look at whether women choose their partners on or off the pill. And then when they're in pregnancy mode, when they're like try or trying to conceive mode in the app, whether or not it takes them longer to conceive based on whether they chose their partner on the pill or off the pill, because I think that it's a really important question and I think that it's one that a lot of women would like answers to. >> Oh my gosh, I've never even thought of that. I've always looked like I've had a number of people on the podcast where I was like, "Yeah, you can increase the likelihood you you'll have a baby by like changing your diet, getting healthier, doing all these metabolic changes."

Um, like there's things you can do to deal with infertility. I'd never considered that though, right? That would be crazy. >> Yeah, it would be crazy. But it in some ways to me it feels like it would be crazy if we don't find it. You know what I mean? because I I I just can't help but think, you know, when there's a reason that estro, you know, that estrogen when it's rising across the cycle and is peaking at times when conception is possible from sex, like there's a reason our brain is really attuned to the differences between men during this time. And presumably, it's because it matters. >> Yeah. >> And and so I would expect that we might see that you do get more difficulty. And again, do I think that this happens with everybody?

Probably not. It might be like the 20%, you know, or the 25%, but that's like a 20 or 25% risk that most women wouldn't want to take if they knew that that there was this that this was a possibility. >> That's crazy. >> Yeah. No, totally crazy. >> That's crazy. >> It's a complete scam. >> I'm from Canada, too. When I found out how much it costs for like schools in the States, >> it's almost unfathomable. >> Peterson Academy. If you want an actual education, join us. The progressives hope for universal education at something approximating zero cost. That's what we've got.

They are the best courses that have ever been offered publicly in terms of their quality of content. Also, the production values are unparalleled. >> The period brain. >> Period brain. >> So, you went from the birth control pill and then now we're focused on the period brain. So, like tell me what is this about? >> Sure. And why why should people care? >> Yeah. people. No, so the just to just to put it nicely. Yeah. Um, no.

So, no, I love it. I love it.

What The Period Brain Is Really About

No, so the period brain is really about what a naturally cycling female brain is doing. And you know, there's for a very long time, and this is one of the things that I talked about in my Peterson Academy class. Um, I think women have been led to believe that the only way forward in terms of minimizing sexism and to promote negalitarian society is to not is to deny our biological differences for men. >> 100%. That is definitely what I learned. Like at least dad was good, but that's what I learned growing up from everybody else and kind of internalized, >> right? Yeah. No, with this idea that the most feminist thing that you can do is ignore your hormones, basically. >> Yeah.

And so this book is sort of an antidote to that in a lot of ways. So it's like it's about embracing the female brain and the hormonal changes that women experience across the cycle, beginning to understand what your brain and your body are actually trying to do as you move between different cycle phases. And then being able to give you a language to understand what your body and brain are doing in a way that I think really is going to allow women to feel more comfortable in their bodies, understand their bodies better, and also um in the end get rid of PMS.

Why Health Insights For Women's Health Have Been Wrong

And the reason that PMS even came into the picture is, you know, when we look at um what is mostly known about like health and functioning in the human body, a lot of that is based on research that was conducted in men, right? Right? We know that men for a long time were the only ones who were studied. And so most of the insights that we have about like what it looks like to have a heart attack or what good nutrition looks like or what sleep requirements look like or what it means to age well, a lot of that's based on research that was conducted in men. And then it was only more recently that women got brought into the picture, you know, where they started including women in research. But the only time that they were in Yeah, I know. The only time they were including women in research was in the early st like the couple first couple of days of their menstrual cycles when hormone levels are low.

And they're doing that to make women most like men, right? And that makes the data easier to interpret because you don't have to worry about the messiness of women cycling hormones. But it also means that a lot of the things that we think that we know about what our bodies need and like what our bodies are trying to do is based on the first half of the menstrual cycle. And it doesn't always work in the second half of the menstrual cycle. And that's the reason a lot of women feel so terrible during the last two weeks of the cycle is because we've been sold a bad bill of goods about what our bodies need at this time. >> Oh my gosh. Okay. Okay.

So, what I think I said, why should people care? Because I know nothing about this really, which is shocking because I know quite a bit about health, but I was like, hormones. >> Yeah, hormones do whatever hormones are doing. I'm not so like tell me what happens throughout the cycle and what are women doing wrong in the second half to lead to PMS. >> All right. Absolutely.

What Happens During The Cycle

So, first let's just talk about a cycle, right? And what it looks like and on the first day that you get your period, that's the first day of your cycle. And on that day, hormone levels are really low. And when hormone levels are low, that tells the brain to start stimulating the ovaries to stimulate egg follicles. um because your body is going to start to prepare for ovulation. And so egg follicles will start maturing. And as they're maturing, that causes the release of estrogen, which is women's first primary sex hormone. And estrogen is orienting the body, like its job in the body is to orient the brain and the rest of the body toward attraction and sex, right?

Because this is a hormone that rises and peaks at a time in the cycle when sex can lead to conception. And so essentially, you can think of of estrogen in your body as just like getting every cell in your body oriented toward being optimized for attraction and being able to tell the difference between good partners and bad partners. And then sex. And so what we tend to find is that when estrogen is high and rising across the cycle, women have higher sexual desire. They have more sex. They're more interested in men. Like they're more easily distracted by men.

They're more easily distracted by flirtatiousness. I mean, it's just really they feel sexier, they have more energy. Um, I mean, it's they smell sexier to men, they move sexier to men, their voices sound sexier to men. I mean, it's essentially just like getting women optimized for sex. And so, that happens. You know, we get uh estrogen rising during the first 14 days of the cycle. So, we're just assuming a 28 day cycle, which isn't true for everybody, but we're just going to use that for um to make things easy.

And generally ovulation will will occur on day 14. Right? So estrogen rising rising rising rising rising it peaks and then you ovulate. All right? And the five days prior to ovulation and then the day of ovulation itself is the time when sex can lead to conception. And that's when estrogen is high and then estrogen drops. And the empty egg follicle that just released that egg after ovulation actually becomes a temporary endocrine structure.

Just meaning that it starts to release hormones. And so it releases women's second primary sex hormone, which is progesterone. >> I didn't know that. >> Yeah. >> That's where the progesterone comes from. >> It comes Yeah. So if you don't ovulate, no progesterone for you. Which is also another thing I talk about in the book is about how easy it is to disrupt ovulation and why so many women's hormones are all out of whack because they're not ovulating. And so they're never getting this really nice influx of progesterone, which is really good for the brain and really good for the body. >> Wow. I can't believe I didn't know that. Yeah, that's crazy. >> Yeah, it is crazy.

So, so you have this and it starts releasing this other hormone progesterone and that gets released for 12 12 to 14 days generally and during the release of this hormone. This is optimizing our body for implantation and pregnancy, right? And so it's like women have to cycle because our bodies have two jobs they have to do for reproduction, sex and pregnancy, right? Men only have one hormone because their bodies only have one thing to do is just sex, right? And so the first half of the cycle is about sex and attraction. The second half of the cycle which is coordinated by progesterone is orienting your body for implantation and pregnancy. And this causes um immunological shifts.

It leads to metabolic shifts. It leads to sexual shifts. And a lot of these things aren't things that women are told about. And the result of it is that a lot of times we feel worse than we need to. And just to give you an example of this, our our resting metabolic rate increases between about a seven to 11% in the second half of the menstrual cycle because your body is working harder to differentiate cells and build the endometrial lining and this makes our body temperature increase, which I'm sure you probably have heard about because when you get pregnant and everything, they tell you about how your temperature rises in the second. >> I've I need a break from pregnancy. I've spent way too many months pregnant in the last couple years. >> Seriously. And yeah, it makes your body run hotter and your metabolism increases by, like I said, 7 to 11%.

Energy, Appetite, and Exercise Across the Cycle

And what this means is that for a naturally cycling woman, when she's in the second two weeks of her cycle, she needs an additional like 140 to 200 calories a day. Now, women aren't told this, >> right? Through that, >> you burn through that. Yeah, you burn through it. So, your body's working harder and it's burning more calories and we're not told about it. And so, what happens? We're following one-sizefits-all nutritional guidelines and then we're feeling hungry and angry and having food cravings and thinking that there's something wrong with us.

But the problem is we're just we're not eating enough because our body is telling us to eat more but the nutrition guidelines that we've been given tell us not to and then the result of that is that we feel terrible. >> Interesting. And same with like our recovery needs also change and it's harder for our bodies because our respiration rate increases in the second half of the cycle along with our temperature. And what that means is that our body is always got to like its baseline is working harder. And this means that um recovery is going to take longer because the body is is working harder. And so recovery oftent times requires more time when you're in the second half of the cycle compared to the first. And again, women are given one-sizefits-all set of recovery and sleep standards. And then if they apply that to their life, they're feeling tired and like they don't have a lot of energy in the second half of the cycle.

But it's because they're not giving their body what they need because our bodies need different things as we're in different hormonal states. And another example is um the changes that we get in sexual desire. Um so women's sexual desire is cyclical and we Yeah. I mean, and it it peaks with estrogen in the cycle and then when estrogen falls and progesterone begins being being released, um, sexual desire gets the brakes tapped on it. And this is something that actually happens on purpose. And it it happens on purpose because when you have when you're having sex, a, it's, you know, unnecessary physiological activity and your body's trying to conserve energy during this time because it's working harder and your metabolism is up and so your body is trying to conserve energy. So, there's that.

But it also um when you have sex because you're introducing nonself like material into your body, it's somebody else's DNA. That's something that your immune system is going to notice. And um and it can cause inflammatory activity near the cervix and the side of the vaginal canal. And that's near where the implantation um you know all takes place in the in the uterus. And having inflammation during times of implantation isn't an ideal setup for an embryo to implant. And so one of the ways that our body deals with this is it turns the volume down on sexual desire um during the second half of the menstrual cycle. And when we do have sex during this time in the cycle, it tends to be more about connection and creating um the connection between yourself and your and your partner and reinforcing the pair bond than it is about just needing to scratch a sexual itch, which is what sex is more about in the first half of the cycle.

And so there's this really, you know, >> there's so many women out there who feel broken and feel like there's something wrong with them because, you know, their sexual desire is cyclical and they don't understand that, right? They're not told that this is actually the way that it's supposed to happen for women. Um, and there's a lot of women who feel broken because they're having food cravings and they they can't understand why they feel hungry all the time and they feel like their body is the enemy. And a lot of that is just because we've never really been given a good idea of what normal looks like for a woman. And that means cycling. >> That's that's crazy. >> Yeah. >> My experience.

Coming Off Birth Control: Mood and Identity Shifts

So I started birth control when I was like 14 for skin issues. And I took whatever the pill is that like you kind of bleed every 3 months, although it's not like an actual cycle. >> Yeah. >> Anyway, I was on that for like quite a long time. So all throughout my teenager, teenage years, and then like early 20s, 22 or 23, when I started to get healthy, I was like, >> I need to get off of everything I'm taking and what is the pill doing? >> Um, which is horrifying. So if people should definitely know what I was going to ask, what about people who just have messed up hormones, right? like that aren't going through these rise and falls of like estrogen and things. >> Do are there solutions? Is that mostly a metabolic issue >> or it's just too complicated to figure out? >> Well, and I think that there's I think that there's some, you know, there's some recurrent players in having messed up hormones. You know, it's it's a lot of times when women have and and we're just going to put like menopause and pmenopause on the shelf for right now because you do get a lot of hormonal variability that goes on during that time that is I mean it's healthy and normal. it's just unpleasant. And um and so there there's not like a real solve for that except for managing the unpleasantness with um you know, hormone therapy or whatever um it is that women want to do to try to iron out some of the the issues they get in parameopause.

But for like a a health, you know, reproductive aged woman with like a messed up cycle, I mean, if you have something like PCOS, it's usually a metabolic issue. um usually due to insulin resistance. And so anything that you can do to try to get insulin resistance taken care of usually leads to a normalizing of cycles. And the same is true for a lot of um irregularity in cycles is that a lot of it is just a matter of not having good physical health. Um, and when you do things to promote the health of your body, and it's not just about like, oh, you know, eating healthy foods and exercising, although those things matter, but it's also about finding ways to actually manage your stress. >> Yeah. How much does stress actually matter for hormones? >> Huge. So, yeah. Yeah.

So, I know it's like, sorry, it's like tough, you know, tough tough luck for you. Tough luck for all of us. Um, yeah. No, it's a like both stress and then having social relationships are incredibly important in um in in in successful ovulation. And the reason for this is our body is so freaking smart that you know our our brain and our body wants absolutely nothing to do with ovulation if it's not in a context in which pregnancy would be a good idea. And so our brain takes in information about what's going on in our environment on the outside, which means do we have a village, right? Do we have social support?

Stress, Safety, and Hormonal Health

Do we are we able to manage our stress as well as our internal environment? Am I getting enough energy? Is this person chronic? Does this person have chronic inflammation? Is there an imunological event going on right now? And if like if you're sick or you just get a vaccine, um those things are going to cause an imunological event which will prevent ovulation or at least delay it until the imunological event is over. This isn't to say that vaccines cause infertility.

They do not. It's just that it will usually make your cycle later by a couple of days because your body doesn't want to get be releasing an egg when it's got an inflammatory event going on. Um and so our our body is really smart. It listens to the inside of our body and the outside of our body and then makes a determination, you know, about ovulation. And if it's not a great idea, if this is not the type of internal or external environment that's going to be supportive of pregnancy and childbearing, then um ovulation oftentimes will get suppressed. And then if it is if we take steps to do things like spend time building community, right, and and having people that we feel socially supported by and making sure that we're getting enough healthy foods that are nourishing our bodies and that we're taking steps to minimize stress so that way our brain doesn't think that, you know, we're in the middle of a saber-tooth tiger den because our stress response is going off all the time. Um, when we do the these things, it really does help to normalize cycles.

And just to tell you what like how big of an issue it is like failure to ovulate within a population of healthy people, I'll tell you about my experiences as a researcher, which was really surprising to me. Um but when I first started in you know doing research on the effects of women's cycles on their motivational states um we would have women come into the lab and we would only um invite to participate um women who don't have endocrine disorders, women who are healthy, women who report having a regular, you know, like 20 26 to 35day menstrual cycle. That's predictable.

Stress and Ovulation Correlation

And we did this because we wanted to be able to isolate ovulation and then look at how the hormonal changes around ovulation impact different types of motivational states. Well, we started doing this research and when I was doing the research and we're trying to confirm ovulation in these groups, what we were finding is that about 30% of these women with these regular menstrual cycles weren't ovulating. And I was like, I must be really messing 30%. And this is women ages like 18 to 25. So >> with regular cycles >> with regular cycles, no endocrine. Yes, we were not like failed to ovulate on that cycle. >> Hold on. Wait, pause.

How so? If you don't Maybe this is a really stupid question, but if you don't ovulate, I thought you didn't get a period, right? >> No. Well, sometimes you do >> without ovulating. >> Yes. So, here's the Yes. Yes. Yes. It's just that it's just not going to be like a a real period. >> Yeah.

Yeah. But you still bleed. >> You'll still bleed. >> What? >> Yes. Because of often times what will happen when women fail to ovulate is that they they start their body starts the process and it's maturing egg follicles and doing all the things. And so the endometrial layer is starting to proliferate and then hormone levels will kind of you know struggle and cough along high at a high enough level where um the endometrial layer will be supported for long enough to seem like at a regular cycle and then when it starts to fall um then you get your you get your period but it's not like a full you you can have like something that's not a full or complete cycle um and still get a period. >> And so this crazy Yeah. No, it is crazy. >> You said 30. So, was that happening to 30%? >> Yeah. So, so, so we found in our sample that 30% of the women were failing to ovulate.

And so, we said, "Wait a minute, we have to be doing something wrong." And so, I called my colleagues in the research area because there's a lot of us who study the same type of stuff. And so, I called some of my colleagues and said, "I'm finding 30% of women in our samples failing to ovulate. Like, what am I doing wrong? Here's our procedure." And they they came back and said, "Oh, no. That's that's typical. is usually about 30%.

And these are college women and a lot of them are under intense stress, right? And there was some research that was done looking at the social isolation that occurred um with COVID and that led to there was a really cool sample um that was collected of of data looking at women's cycles during um during isolation. And what they found was that a lot of women were suppressing ovulation in that context as well because it's like the body just wants nothing to do with Yeah. Exactly. It was like why why get pregnant right now? This is not a good idea. Pregnancy for women is so costly as you know.

I mean it's and it's risky. It's like thousands of women still die in childirth every day around the world. I mean it's like not something that your body takes very lightly. And so your body's like eh we'll just wait a cycle. Like this isn't a great time. Like we'll just cut this off at the pass. And then you know like I said and sometimes the cutting off at the pass happens at different points in the cycle.

Sometimes it might be you know you're halfway through the follicular phase. Sometimes it might be you're halfway through the the ludial phase and and hormonal disruptions will happen on purpose because your body is trying to cut ovulation off at the pass and prevent pregnancy from happening. >> So this is also why in relationships the female feeling safe in that relationship is so important. I didn't realize it doesn't just go to like cuz you get I I've had this. You meet people and you're like >> the vibes off. I'm going to danger your vibes. And I think a lot of like young women too when they start dating. They'll confuse >> danger with excitement.

They'll be like, "This person's really exciting, but you're just getting danger vibes and you just don't know how to differentiate." >> And then there's like safety with some people. And I didn't realize that goes all the way down to being important hormonally as well. >> In the relationship is like your ability to have children potentially is how safe you feel. >> Yes. Yes. Yeah. And what's really interesting about that is another thing that I talk about in the period brain is about how during the ludal phase of the cycle, one of the things that progesterone does is it actually increases our attunement to signs of lack of safety in a relationship.

Relationships, Safety, and the Female Brain

And it, you know, if you think about your brain as like a smoke detector when it comes to threats, where if it senses a threat, the smoke detector goes off. Um, our brains are the same way. And the sensitivity of the smoke detector to the smoke of lack of safety becomes more deeply attuned when our body's preparing for the possibility of pregnancy during the ludal phase of the cycle. And so during this time in the cycle, our amygdala, which is the fear center in the brain, actually becomes more interconnected with other areas of our brain. And it makes us more sensitive to even slight differences in the environment that may signal that we are not safe. And this is why a lot of women will become more emotionally sensitive in the second half of the cycle and they think that they're just being crazy, but essentially it is their safety and security mechanisms, right? Just becoming extra sensitive to the outside environment.

And so one of the things that I talk about in the book is just this idea that recognizing this in yourself and when you're in the second half of the cycle if you're having one of those moments and we always I most people recognize even if they don't recognize it in the moment they'll recognize it after the fact where it's like you get really upset about something that may not have upset you two weeks earlier. Like let's say that your partner loads the dishwasher the wrong way in the way that you know that you know they know that you don't like it that way and they do it anyway. It's like during the ludal phase of the cycle, the brain is like, "Wait a minute. Does that mean that I'm not safe? Does that mean my partner like that they don't value my needs?" And and it really does become um you know, and when you ask yourself the questions um when you're looking at how you're responding to something is like, >> "Am I feeling this way because I'm worried about my safety? Am I feeling this way because I'm worried about my security?"

Right? And usually it's one of those two things. And that allows you to be able to have better conversations with your partner. So that way you can actually ask for the thing that you need, which is generally just reassurance about safety and security. And once you have that and are able to have those conversations, it really does change the nature of relationships. And I think that, you know, one of the things, um, you know, even the though the book is like about, you know, the a period brain, there's so much in there that makes relationships better when you have the conversations with um male partners about, you know, changes in sexual desire, changes in the sensitivity of your smoke detector in your brain with things related to security and safety and um, and then being able to recognize together when, you know, certain dynamics are taking over and so that way it it really can lead to I think more intimacy and then also just better relationships. >> Yeah, you have a manifesto for women on here but but like part of the reason we wanted you on board for the course was because I think everybody needs to know this stuff if you're going to have a relationship or be friends with a female as well or marry one and live with one. >> Yes. No.

No. 100% is like what are we 50% of the population is female. And so even if you're a man who's like trying desperately to avoid women, >> yeah, good luck. >> You're probably going to have to interact with us at some point in your lives.

Sexual Desire Isn’t Broken—It’s Cyclical

And um and really understanding this stuff and you know, and I've told a lot of people this um but so when my first book came out um there was this one I have one chapter and it's just about sexual desire and the way that estrogen and estrogen changes across the cycle influence sexual desire and attraction and so on. and um and it was like maybe a third of the chapter was talking about women's, you know, the simplicity of sexual desire. I have gotten more emails from men who read my book and read about that and were like, "Oh my gosh, you know, this is so helpful to me." Because anytime that my partner didn't want to have sex with me, I was feeling like bad about myself. And then I would feel like I needed to pester and persist with sex just to prove something to myself because I'm feeling insecure about the relationship because they don't want to have sex with me. And so then I'm feeling like I you know and then I found that I was chasing my partner down and then they would would turn me down and then I'd feel worse and you know lead to these loops because men are sensitive you know even though they don't want to admit it and if they're you know pursuing sex with you as a as a partner and you're saying like no you know and and not right now that they usually think that it's because there's something wrong with them or something wrong with the relationship because for men that's often times the only times that they don't you know that they're not like interested in sex. And so to have that lens where they're actually able to understand it is so helpful to a lot of men because it's allows them to recognize that that they're they're not undesirable to their partner, you know, and that there's nothing wrong with their relationship and that they can relax on that because most men, especially in long-term relationships, you know, they can have a little, you know, they can have flexibility around women and a lot of the feeling like, "No, I have to have this right now." Um, even though my partner is saying like like she doesn't want to do it.

Um, a lot of it is is just internal ego struggle where they're just needing to feel better about themselves because they're worried that their partner's turning them down because there's something wrong with them. >> You know what? I don't even disagree with that. No, >> it's definitely true. I realized So, I was going to say I when I went off the pill, I was shocked because I went on it at such a young age like >> which is just a bad idea. I I hadn't like had cycles really naturally, right? And I was shocked that like >> I realized for the first half of the cycle I could smell people. >> So that was weird. Whereas I'd be walking next to someone be like I can smell them more than I used to.

Like I was like I didn't realize I could smell people. I felt like a dog. I was like wo that's weird. So that happened but I also started getting the mood fluctuations but in like it was better. Yeah. >> And then for the last half, okay, now I can really work. >> So it was like the cycl of like fun and then okay, work, fun, work. It was like, oh, that's weird. No, that's so funny.

No, I I very much um notice simplicity in my scent detecting and and I always have. Oh, yeah, for sure. And and there's research on this. Like so women actually become their sense of smell and particularly to things that are related to like masculinity.

Sensory and Emotional Changes Off the Pill

So for example, there's been some research done looking at sensory thresholds for metabolites of of uh testosterone. And women become more sensitive to that like their sensory threshold lowers. So they they were able to tell the differences between these things in ways that they're not at other points in the cycle. And you know for women uh scent has a lot to do with I mean that plays a role in partner choice. It it just does. And um and and during the times in the cycle when sex can lead to conception, this is when it's most attuned. It's most like finely tuned and having those you know the the cycle based differences in um in yeah just like sort of the degree to which you're externally facing um and and you know like not really wanting to do work and wanting to go out and have fun and then like being able to buckle down.

Um yeah, that's so normal. I mean, it's it's it's so common to experience those shifts, and I know in my own life, I definitely have. And and for me, when I went off the pill, I remember um thinking to my like self that when I was on it, I was kind of like a like an ant drone, you know, like like where it's like you're a worker drone where it's like I just like keep my head down and like move forward and like nothing was distracting and nothing was fun, nothing was pleasurable, but I thought that I was enjoying my work, but it was just like work, work, work, work, work, work, work. And then when I went off of it, I was like like I was like an I'm like I was like a worker ant. >> And now I'm not. And it's so much more fun, you know, and I was still able to get just as much done as I did. It just has a different rhythm. Yeah. >> You know, and so I also think that um you know, I think that there can be a fear if women are like, "Oh no, I don't want to lose my productivity."

You don't need to lose your productivity. It just becomes different. >> It's just you just ride the you ride the cycle and it's it's just a totally different experience. >> Oh yeah. I don't think it makes you less productive at all. >> No, me either. >> If anything, like I I'm sure it was contributing to me being depressed >> because like everything was, but like I'm sure. And so if if that's what it's doing to you, but you're a worker ant, you're definitely still less productive than you would be if you were not depressed period. >> Yeah. You know, >> yeah, it's more fun. >> Yeah, I know. I So, I had the same experience. Um, and it took me almost 10 years being off of hormonal birth control to like actually rewrite the narrative I had about myself.

But I had a belief about myself or I believed that I was somebody who was a little depressed and a little anxious. And I thought that's who I was.

Rebuilding Identity After Hormonal Suppression

And it took after, you know, it took me being off the pill for more than 10 years to realize that that was never me. You know, it just cuz it wasn't that's just not my personality. I'm not somebody who gets >> such a shame. >> It's like I'm not somebody who gets depressed by things, you know? I'm a I'm a pretty gritty person. And so when when something sets me back, I'll feel sad for a day and I jump back up the next day and I just keep moving forward. And and that was not me when I was on the pill. Yeah.

And um yeah, it was really crazy to have to rewrite my internal dialogue that I had. >> I had that same experience. I had some other medications like mixed into it. So it was a >> cornia. Who knows what was going on, but it was the same thing. So I went off of I think anti-depressants were like the big one, but anti-depressants and birth control kind of at the same time. And I had to rewrite like, oh, I'm actually extremely stress tolerant. >> Yeah. when I didn't think I was stress tolerant at all. >> I was like depressed, volatile, >> like I'm I'm not. >> Yeah. >> Yeah. It's really >> especially during your developmental years if you're on that then it's like who am I afterwards? >> Well, no, I know.

And so many women don't get to figure that out until so so late in life because they're on it for so long. And a lot of them if you ask them it's like so how do you feel on the birth control pill? Because if you would have asked me, oh, I'm fine. I'm great. Like this is good. I'm good. Um, and then it was only after I went off of it that I realized, no, like I missed out on this whole, you know, other aspect of life that I and and and a totally skewed view of who I was.

And like I said, it took 10 years of being off of it to finally actually rewrite the narrative because, you know, when you go through young adulthood, you're figuring out who you are and what your personality is and everything else. And all of that was developing for me and it sounds like also for you when you're on a medication and that your identity gets built around the medication >> and how you act and how you respond to things. Yeah, of course. >> Yeah. And so it takes a long time then to to grow into the new identity. And like I said, yeah, for me it took about 10 years and and and I'm finally starting to rewrite the narrative. But yeah, like you, I felt like I didn't have good stress tolerance. I felt like I would get easily depressed if things weren't going the way that I wanted them to. that it would um that it would really, you know, sideline me and um and that's just not who I am. >> Yeah.

Yeah. Crazy. Do you think it took like 10 years of recovery was that mostly like a psychological thing having to figure out who you were as opposed to like hormonal things? >> Yeah. Yeah. Uh so you know generally what we tend to find is that after women go off of birth control that within one to three cycles that their hormones are doing I mean that they're ovulating and they're producing hormones and the same levels that they should be and there are still a lot of adjustments that have to go on just in terms of um your the receptors for the hormones have to become more sensitive to hormonal changes because when you're on the pill and you get the same daily hormonal message every day, your body doesn't become used to having to adjust, right? like, "Oh, there's lots of estrogen. We better dial back the receptors." Like, "Oh, there's not a lot of estrogen.

We better increase the number of receptors." My gosh. >> Yeah. And so, thankfully, I know thankfully our brain is is very plastic, but it can take some time for, you know, for our bodies to adjust when we make big changes like that. But I I think that the bigger change for a lot of people and certainly for me was really it was the it was the identity thing because it's like you know we don't have and this is like this crazy psychology thing um but it's which sounds dumb but it's like so interesting when you really think about it you know we don't have any special insight into ourselves you know we have to learn who we are by watching ourselves the same way other people do. That's funny. But yes. >> Yeah. But it's but it's true, you know.

It's like um we don't have nobody gave us the guide book. Like you don't say like, "Oh, like Michaela likes this and Michaela does not like that. Wouldn't it be wonderful if we did have that?" >> But we don't. And so we just have to figure it out based on experiencing life and what's good and what's not good. >> And um so our identity takes a really long time to build. You know, it takes years of experience and observing yourself and saying like, "Oh, I respond in this way." And after having 10 years of not having resilience to stress or 10 years of going into a depressed hole when things aren't going my way, you know, it takes it takes more than a couple months of of observing myself sort of responding in a in a better way and in in a more adaptive way. Um to to rewrite the the selfnarrative that that I had.

That was I think that was the craziest part of like my experience getting better and kind of auto out of out of autoimmunity and um mostly the psych issues and like putting them behind me was there was a period and there were some other variables at play with like >> some medication withdrawal and stuff like that. But um I didn't know who I was at all and like >> bounced around to different things being like well I seem to be acting in this way so am I like this? in when I first stopped taking anti-depressants um I spent a year maybe in kind of a hypomomanic first I got really depressed then I went into like the hypomomanic period which was a fantastic year >> got a lot for me I it felt great but I was like I I wasn't feeling guilt and it was misplaced guilt when I said no to people cuz I used to have bad boundary issues so I stopped having any guilt with saying no so I'd just be like no you know I'm not doing that and I was like maybe I'm actually just a terrible person. So then I spent a year being like >> I'm a terrible person, but I don't seem to care. >> And then that kind of but I went from like super depressed to like >> way too many boundaries in maybe a rude way, too much positive emotion. And I think part of that was all me being like I have no foundation for like what's my actual personality? Like >> right. Wow. >> Having to just figure out who I was. Anyway, it all stabilized.

It worked out in the end. But like >> Yeah. But I mean think Yeah. your brain. I mean, especially with, you know, with anti-depressants, it's like when you're messing with neurotransmitter, I mean, levels is there there's receptors for those things all over the place in the brain. And so, you're having to like rewrite the whole script. And so, yeah, I'm sure that that's a real bitch to get off of it. Really, really, really bad.

Would not recommend. Yeah. >> Yeah. Wild. Okay. Well, that was amazing.

Final Thoughts & Where to Find Sarah Hill

That was so informative. People should definitely check this out. Your last book was amazing, too. >> Thank you. >> This is very exciting. Thank you so much for coming on. That was amazing. I can't believe I didn't know about your ability to get a period even if you don't ovulate. I didn't know that the body could do that. >> Yeah.

Some women will still bleed and they have no idea that they didn't ovvelate. >> Yeah. >> None. >> Huh. >> Cuz they start to release estrogen proliferation. >> Yeah. Wow. >> Yeah. Anyway, people should definitely know about this stuff. >> Yeah. No. Yeah, for sure. And so, and in in in there, we also talk about ways to identify whether you're ovulating given that you can still get a period and also talking about ways to support ovulation and ways to support your changing self across the cycle. And yeah, I think it's good stuff. >> I think it's good stuff, too.

Thank you. Ken, if people want to follow you, obviously they can buy the book, but where should they go online to follow you? >> Sure. They can follow me on Instagram. That's where I'm most active and it's uh Sarah Eh Hill PhD and that's Sarah with an H. And you can find me online. My website is sarahehill.com. >> Perfect. Well, thank you again. >> Thank you for having me.