Hi! I’ve been thinking about you.
Did you know that you can fortify your baby’s mental health in your sleep, just by lying beside them?
It’s true.
My friend and neuroscientist Dr. Greer Kirshenbaum wrote the book on how nurture from the age 0-3 impacts long-term resilience and mental health.
I called and asked her a bunch of nighttime-nurture questions about this recently, and I recorded it for you!
I hope our conversation blows your mind, as it did mine. And I hope the broader context of what’s happening when you sleep beside your baby helps you on the hard nights.
Hit play above to listen to our 15-minute chat during your next contact nap.
Or you can read the transcript below, if that’s easier. 🫶
Afterwards be sure to connect with Greer on Instagram and dive deeper in her best-selling book The Nurture Revolution.
DR. GREER KIRSHENBAUM:
The person who gave birth will start to have brain changes during pregnancy, and then the dad, partner, or parents (with surrogacy or adoption) — their brain changes will happen in the first three or four months after the baby's born.
TIFFANY BELANGER:
That's crazy. But how? What about a grandparent who comes over every day and does contact naps and stuff, what's happening in their brain?
DR. GREER KIRSHENBAUM:
That same thing changes. We see it in alloparents, people who are spending a lot of time with the baby. So grandparents, caregivers, anyone who holds babies and does contact naps.
And it happens, actually, in a dose-dependent relationship. So the more time we spend nurturing, cuddling, smelling, playing with babies, the more our brain changes.
And a lot of it's mediated through the hormone oxytocin. When we are interacting with babies, our brain and body will get tons of oxytocin. We sort talk about it like bathing our brain and bathing our body. And the baby does too. And when we are in this exchange, both of us are growing.
TIFFANY BELANGER:
But what do you mean by growing? What does the oxytocin actually do?
DR. GREER KIRSHENBAUM:
It really influences how circuitry is changing in babies, because babies have about a million connections per second growing in their brain.
And so the oxytocin will influence that development to actually grow the brain to be more resilient to stress and mental health issues later on. And that works on an epigenetic level, on a brain connection level. It wires neurotransmitter systems, all kinds of things like that.
And in parents, we have major brain reorganization happening and oxytocin is actually a calming agent in our brains as parents.
So our fear-center is heightened because we need to be attending to things to take care of our baby. Are they eating enough, drinking enough? Are they breathing properly? We have to always be aware and scanning is there danger?
But the presence of the baby through oxytocin will actually quiet our amygdala and actually gives us that feedback of baby's safe. And then our amygdala grows with that safety signal. And so it's not necessarily growing towards more fear, more anxiety, which it might in the absence of close.
TIFFANY BELANGER:
Okay. So I've heard from many parents who've said that once they started bedsharing their PPA or PPD lessened. So my question is do you have to be conscious in order for this to be happening to your brain? What if you're asleep next to your baby?
DR. GREER KIRSHENBAUM:
Yeah, no, absolutely not. I've heard that from so many parents — having one consult with a parent. They're like, instantly, it's all gone. Just the information sometimes that sleeping close, it can be safe and is actually beneficial... Some people just have worries even just about that.
Then the actual act of [bedsharing] will also impact their physiology, too — towards more health, away from more anxiety and depression.
And it can happen when you're unconscious because we still have our senses active to a degree when we're unconscious, when we're sleeping.
And so babies and parents are both receiving touch, smell, sound, and all of those signals go into our body to signal safety. And then you also have oxytocin, dopamine, endorphins, all these other things too.
TIFFANY BELANGER:
It just makes sense. If your baby's sleeping in a bassinet across the room or back in the day they were in a separate bedroom. Even when you're asleep, I feel like you still, unconsciously your brain might still be on that high alert, sort of hope they’re breathing in there, hope everything's okay.
But if they're right next to you and you're hearing them breathing in and out or feeling their little touches every now and then, even though you're asleep, that means your brain is being flooded with the oxytocin. Right?
DR. GREER KIRSHENBAUM:
Yeah. You think about James McKenna sharing in his book about parents who have been alerted to their baby having breathing issues in the middle of the night. That shows us that when we are sleeping, we're still monitoring our baby and our baby's health.
I mean, I've heard from so many people easing of anxiety and depression postpartum. I've heard some people say they've gone off different psychiatric medications after becoming a parent. And so much of it is from some of that brain wiring.
The areas that are involved in mental health are rewired through nurture.
TIFFANY BELANGER:
That's crazy. That's mind-blowing to me.
DR. GREER KIRSHENBAUM:
Yes. And traumatic brain injury, people get healed through becoming a parent again, because you have all of these mechanisms that are really helpful, and we usually hear the opposite. We usually hear, “Oh, you can't remember anything. You are useless.” All these derogatory things about moms especially, but also all parents.
But it's actually, no, our brains are just different. We can do certain things really, really well. Take care of our baby, empathy, theory of mind, all these incredible skills.
And the brain changes, and other things aren't as strong.
TIFFANY BELANGER:
But I wonder if there was a mom who didn't want to cosleep or bedshare, and she had her baby and did everything according to the guidelines. And so she had her baby in a crib across the room for the first six months, and she was up every few hours or more trying to nurse feed them, get them back to sleep, do all the sleep associations or whatever works to get them to go back to sleep on their back in the crib.
She's going to be very sleep-deprived. And maybe it's true that she won't remember anything and all the things you just listed, maybe that is true for her, but maybe if she slept as humans have been sleeping for so much of our history and she slept nearby or within arm's reach of her baby, maybe she would benefit so much more.
DR. GREER KIRSHENBAUM:
That's true because there's such a big difference between fully waking up. I always say, and someone said it before me, it's not my thing, but if your feet don't touch the floor at night, there’s a huge difference in the amount of rest you're going to get.
TIFFANY BELANGER:
Wow, I've never heard that. That is so true.
DR. GREER KIRSHENBAUM:
I think I must've heard it in one of my doula trainings to help parents. If you can have the baby right beside you, either bedsharing or right next to you, attend to them without getting up, walking to the other end of the room or the other end of the house or whatever it is, then it’s going to be.
And that's a huge part of [what I do] when I work with parents. Sometimes if we don't, a baby's still waking up the normal amount of times… But if we're changing the way the whole sleep setup is, it's a completely different story.
If a mom isn't fully waking up, feeding a baby, getting them calm, getting them back in their crib, and then going back to sleep and then being woken up again, right?
TIFFANY BELANGER:
Yeah. I'm just so fascinated by human evolution or just how maybe our brains have become what they are through however many years of sleeping beside our babies. So if in recent, let's say the last 500 years it's been separate crib sleep, that's just not what we've always done. Our brains aren't wired or evolved to succeed and thrive under those circumstances.
Do you talk about that in your book at all? Our history and how our brains have become what they are now?
DR. GREER KIRSHENBAUM:
I mean, think I do a little bit. I really talk about how so much of modern baby care is about one or 200 years old in a history of 200,000 years of taking care of babies. And I think the point you make is so true. We're probably not made to be sleeping far apart. Look at any other animal on the entire planet with anyone else do that.
TIFFANY BELANGER:
Well, I think if we were doing crib sleep and we were reaping some sort of benefits, then we could say, “Oh, this is beneficial,” or “We've evolved to be able to thrive under these circumstances.” But clearly we're not getting the oxytocin or anything else.
It seems like it's increasing anxiety and it's making us more tired physically getting up out of bed and doing all these things, all the benefits we're receiving in our bodies as parents. Doesn't that happen when we're close by, as you talk about, within an arm's reach?
DR. GREER KIRSHENBAUM:
Absolutely. Yeah. It's true. Even though I never thought about it that way. Even though you'd still call that responsive to be going to the baby every time they woke up, maybe the baby would get the benefit of that responsiveness.
But neither are getting the benefit of being within arm's reach where we need to be to be getting all those safety signals from each other.
TIFFANY BELANGER:
Because it's only when we're touching or are within sensory proximity. So we go to their crib, we get them to sleep, they might have had those benefits, but then we go back to our bedroom and nothing, no oxytocin as we sleep.
DR. GREER KIRSHENBAUM:
Unless your partner might give you oxytocin…
TIFFANY BELANGER:
[Laughing] Oh man… We’re way too tired for that. Are you serious?!
That's so fascinating. Okay, so I've been curious about how did you stop at age three or how do we know that's sort of where these benefits end?
DR. GREER KIRSHENBAUM:
Yeah, I mean, I wouldn't say that's where the benefits end. I still bedshare with my son. He's five, and he knows he can choose when he wants to have his own sleep space. And now he says he's going to do it when he's a teenager! But we'll see.
I chose to leave my parents' bed when I was around six years old. Other members of my family, cousins, they've chosen around say age seven, age eight, and around the world, that's typical too.
It is certainly beneficial in the first three years of life. And the reason why I talk about those first three years are based on how the infant brain is developing, and more specifically how the emotional systems in brain are developing in the first three years of life.
And so that's sort of what we would call a sensitive window for building a lot of the parts of the brain that underlie lifelong health, both mental health, physical health, relationship health — all of the important parts of health!
So I would say I would wish for every baby to have close sleep for those first three years to sort of be maximizing that sensitive time.
Babies are sleeping sometimes 70% of their life, and that's a massive amount of their experience in those first three years. And so if we are able to provide that closeness and proximity, they massively benefit. And so do we, as parents.
TIFFANY BELANGER:
That's so amazing. So I've been bedsharing for five and a half, almost six years now. How do you think that that's changed me?
DR. GREER KIRSHENBAUM:
I don't know. Yeah, I mean it's definitely changed you, right? You're getting that full dose of neuroplasticity and in combination with neuroplasticity, we also need to have practice to rewire our brain. And so the combination of being close, but also being empathetic and supportive and responsive, I would bet your brain has changed to to have really good empathy, really strong empathy for your own family and others.
You probably get a lot of joy and reward from being with your children and having fun with them. That part of your brain develops as well. I'm trying to go through all the parts right now. I'm thinking your hippocampus, your memory center and your stress regulation center gets enriched as well, so your stress regulation could be better.
And same with your prefrontal cortex too, is also going to get a lot of exercise in regulation and strengthening there too. So your stress system is probably stronger too, in terms of being able to shut off stress and regulate stress.
TIFFANY BELANGER:
That's really cool. So what's going to happen? What do you think happens when both of my boys finally leave the bed and go off into their own space? Will I have a changed brain for the rest of my life?
DR. GREER KIRSHENBAUM:
We think so. Yeah. So we see changes. I'm thinking of one study that looked at 70 year olds of people who had been parents and people who had not been parents, and there were changes at 70.
TIFFANY BELANGER:
That's amazing. This is so encouraging for those who are cosleeping kind of begrudgingly, just because it can be really difficult. And I understand why some people just don't enjoy it, but this is encouraging to know that at least there are real benefits that we know about.
Science tells us that there are benefits for both us and our children. And so the longer that we have to get through it, over time, maybe we'll look back and be thankful that we did it.
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