This one gets in the weeds a bit, but I think it’s important to understand why things are happening, before we try to fix them. My next post, which may be two weeks from now, will take a more personal and experiential tack. It will be a brain dump on stress management, lifestyle, diet and supplements. That one will be for paid subscribers, but today’s labor of love is for everyone, so please share with a friend who might find it interesting.
Have you ever wanted to throw something across the room after reading yet another article on stress management that might as well say, “Find a unicorn to cuddle!”, “Watch the cute pigs fly across the sky!” or “Stare lovingly into your spouse’s face while you recite the alphabet backwards and breathe through one nostril”.
Okay, I’m joking. But, as a mom with an unpredictable sleep schedule, limited time to myself, hormones that have been ping-ponging between pregnancy and postpartum for the last decade, a smattering of childhood trauma, and the demands of my wonderful, but not idyllic, life, the advice in these articles sometimes makes me want to scream. I’m sorry, but I just don’t think your CBD infused soda is going to touch this…
I know I’m not alone, so here we go.
I started writing this, thinking I would try to lay out some of the interactions of stress and hormones and then give you some accessible solutions. All in one article. I know, it was ambitious. What can I say? I guess I’m an optimist. For my sake and yours, this is going to be a two part series.
Today we’re going to try to wrap our heads around what stress is from a physiological standpoint, learn some of how it impacts us, and work to understand its potential effects on hormones. To start, let’s define our terms.
What is Stress?
We like to talk about stress as if it’s all bad, but that’s not true. Acute stress can be a good thing! Stress, broadly defined, is any large deviation from homeostasis, or your body’s ability to achieve balance. The body releases different hormones and neurotransmitters designed to help your body return to homeostasis, which is called a stress response1. You need your stress response to stay alive! The problem, of course comes, when we’ve got a stress response designed to help us run away from bears but it’s being deployed every time our kid screams or we interact with a scary headline on the Internet. Our body’s design is not the problem, but there’s a bit of a fundamental mismatch going on with modern society. When this acute stress response turns into a chronic stress response, we start to feel the wear and tear. Your body’s response to stressors (which, let’s remember could be anything from your kid running across the street, to someone looking at you sideways) is governed by your limbic system. The limbic system, specifically your thalamus, takes in sensory information and then passes it down to your amygdala and up to your frontal lobe. The “low route” is faster, and thus the sensory information reaches your amygdala before it reaches your prefrontal cortex, which you could think of as your “thinking brain”. Then the amygdala’s job is to figure out if this stressor is a threat to your wellbeing and, if it is a threat, to rally the troops (your autonomic nervous system2, which governs “automatic” functions like breathing, heart rate increases etc…3)
In other words, you sense danger before you perceive danger. Your unconscious threat detection system may have determined that something was a threat, before you’ve even had a chance to think about it.
Here’s the cascade of events that your limbic system triggers in the body (this is the simplified version):
Your amygdala, which you could think of as the body’s smoke alarm, detects stress —> sends signal to the hypothalamus —> hypothalamus stimulates production of a hormone called adrenocorticotropic hormone (among others) (ACTH)—> ACTH causes adrenal glands to pump out cortisol —> cortisol acts as a steroid hormone that can modulate heart rate, vasodilation, and other autonomic (think automatic) nervous system functions, thus preparing you to run from the bear, fight the bear, befriend the bear, or play dead. There’s also other neurotransmitters involved in this process of activating the hypothalamic-pituitary (HPA) axis. Some of them will amp up the process, and some of them will exert calming effects.4The HPA axis is a complex system, but it’s designed to have a negative feedback loop, where certain hormones and receptors act as a shut-off to tell the adrenal glands to stop pumping out stress hormones (mostly cortisol). The system is designed to keep cortisol levels within a narrow range, since it’s one of those “Goldilocks” substances. Too much or too little can both be problematic.5
What’s your HPA axis?
Now, I keep mentioning this HPA axis thing — so what is that? HPA axis stands for hypothalamic-pituitary-adrenal axis and it describes the interaction of hormones and neurotransmitters that govern the production of stress hormones. The HPA axis also interacts with something called the hypothalamic pituitary gonadal axis (HPG) which governs your body’s production of sex hormones. And all of these interactions are also tied up with important neurotransmitters like dopamine, serotonin, GABA and oxytocin. The system is incredibly interconnected6. In a lot of wellness contexts we hear about estrogen dominance, or low progesterone, or people throw around terms like “adrenal fatigue” and “hormone imbalance”, and while these are all real symptoms and problems, what is often missing from the conversation is the understanding that what drives your entire hormonal system is your HPA axis.
“Adrenal Fatigue”
Let’s just quickly talk about this term. If you’ve been around the health and wellness world for a while, you’ve probably heard lots of chatter about “adrenal fatigue”. And then if you’ve gone to a doctor to complain about your adrenals, they've probably rolled their eyes at you and told you you’re “just tired”. And you know? You’re both kind of right. There isn’t such a thing as “adrenal fatigue”, or rather, that’s a misnomer. What does exist and is well documented in literature is what is referred to as HPA axis dysfunction. Where the adrenals get dragged into this, and the reason that so many people refer to “adrenal fatigue” is that the adrenals are responsible for producing both cortisol, which is one of the main players in your stress response, and DHEA, which affects sex hormone production. So the adrenals are important, and when the HPA axis is pumping out cortisol in odd patterns, or your total cortisol is very low, it makes sense that someone would call the resulting symptoms “adrenal fatigue”. For one thing, you probably feel fatigued. But it’s important to be specific about the terms, because most MDs are only taught the extremes of total adrenal insufficiency (Addison’s disease) or a massive overproduction of cortisol (Cushing’s disease). There’s actually a huge area in between those where a lot of things can be off, and you might feel terrible, but the best diagnosis7 they can give you is “HPA axis dysfunction”.8
What can impact the HPA axis?
Like we’ve already established, the limbic system and your prefrontal cortex both send signals to your hypothalamus. It’s not that you thinking brain doesn’t have any say in what is going on, it’s just that your limbic system moves faster than your prefrontal cortex. This means that what we sense with our bodies (as in, the sensory information we take in) has a profound effect on our HPA axis. How this actually impacts each individual can vary, but I’m going to focus on a few things that tend to cause the HPA axis to become imbalanced.
Childhood trauma — Adverse childhood experience (ACEs) alter HPA axis reactivity. While there are multiple factors that affect how damaging childhood trauma is, it does appear to alter the body’s ability to respond to cortisol.
Prolonged stress — Chronic stress can also be a huge issue, because when the stressor doesn’t resolve, the baseline “normal” level of cortisol is raised and the body eventually becomes less responsive9 Something that’s designed to be short term becomes long term and maladaptive.
Genetics — Genetics influence how we process neurotransmitters like dopamine, serotonin, norepinephrine, adrenaline and others. Our genetics also play a huge part in determining how sensitive we are to hormone shifts, and how sensitive our hypothalamus is to certain threats. For example, there may be a genetic component to why some people will lose their period or experience hormonal mayhem on a low carbohydrate diet, and others will be fine. It might have to do with whether or not your ancestors were agrarian!10
PTSD — If PTSD is due to either physical or sexual abuse, your baseline level of cortisol tends to be lower, and this has implications for mood, since blunted cortisol response is often associated with depression.11(By definition, PTSD also involves an overactive autonomic nervous system, which I wrote about a bit here, if you’d like a different glimpse into this).
Hormones — This information fascinated me! The HPA axis is affected by your menstrual cycle, with cortisol being higher in the follicular phase (before ovulation) and lower in the luteal phase (after ovulation). However, your reactivity to cortisol is higher in the second half of your cycle. (Translation: you don’t handle stress as well and have less energy in your luteal phase. We all knew that anyway). Cortisol also has large shifts during pregnancy and immediately postpartum, and these cortisol shifts can play nicely or not so nicely with some of the other factors listed above, like genetics, trauma, and prolonged stress. The takeaway from this, is that hormonal shifts are a vulnerable time for the HPA axis.12
Cortisol
Now, let’s talk about cortisol. Many people have this idea in their head that cortisol = stress = bad. But we need it! Cortisol is what gets us up and going. In someone whose HPA axis is functioning properly, the peak level of cortisol occurs about 30-45 minutes after waking up, and then continues to gently fall, reaching its lowest level at night13. Cortisol is the morning wake-up hormone14, melatonin is produced as the night winds down and helps you go to sleep, and both are closely connected to your circadian rhythms. But, under periods of chronic stress your baseline cortisol levels can fluctuate. In many studies, prolonged severe trauma is associated with HPA axis and cortisol hyporeactivity (meaning there is not as much of a response as you would expect), and in periods of acute stress their can be HPA axis and cortisol hyperreactivity (meaning that these systems are too responsive). There’s also a strong correlation between childhood trauma, specifically physical and sexual abuse, and a negative feedback response that doesn’t work as well as it should.15Remember how the system is designed to shut itself off? Prolonged stress and childhood trauma both mess with the natural feedback loops of cortisol production. It can become under or over reactive. So, when you think about the fact that cortisol is one of the primary substances governing a whole host of bodily functions, these variations have some big implications. Cortisol also helps govern our mood, and some studies have floated the possibility that HPA axis dysfunction from stress and trauma closely mimics depressive symptoms.16When you take into account the times your HPA axis is more vulnerable, it makes sense that we see a big spike in mental health struggles during these times. PMS, PMDD, postpartum depression, and perimenopausal depression all have potential connections with the HPA axis and the way our bodies do or don’t produce cortisol.17
Cortisol and Progesterone
Now, at one point, when I got really into studying the idea of adrenal health, etc… there was a concept floating around which said cortisol “stole” from the precursor hormone needed to make progesterone. But the interaction between low progesterone and stress has more to do with the response happening in your brain. Your hypothalamus is keen on you surviving, and if there’s a question about whether you can survive, it’s going to prioritize your survival over your reproductive capacities. The problem with this, is that no one has clued your hypothalamus into the fact that really stressful internet content is not the same thing as being in physical danger. It also hasn’t realized that your trendy crash diet is not the same thing as a famine. Stress —> baby making deprioritized. Practically speaking, what this looks like is that a signal travels from the hypothalamus through what’s called the hypothalamic-pituitary-gonadal (HPG) axis and that stress signal from your brain tells your body to deprioritize the follicle stimulating hormone (FSH) and the luteinizing hormone (LH) responsible for ovulation. No ovulation = no progesterone, because progesterone is only produced by the corpus luteum after ovulating18. Stress is not the only cause of low progesterone19, but it is a primary player. If you’ve ever spent any time in NFP circles, you’ll know the holidays are a notorious time for menstrual cycles to become unhinged. Here’s your reason. I guess there’s something about the most stressful wonderful time of the year that results in delayed or absent ovulation…
Symptoms of HPA axis dysfunction
So, if your cortisol is out of whack and your HPA axis is cranky, what could that look like? This list isn’t exhaustive but a few tip offs might be:
Brain fog
Insomnia and poor sleep quality
Low libido
Mood changes, anxiety or depression
Hypothyroid symptoms
Dizziness when standing (this has to do with another steroid hormone that governs blood pressure)
Cravings for salt or sugar
Weight gain
Fuzzy thinking, or memory issues20
A lot of these symptoms are things women are told are just part of aging, or something you have to put up with. While it may be true that there are parts of living in a broken world we can’t avoid, I can’t help but wonder if we’ve normalized a lot of things that shouldn’t be normal.
Where to from here?
Researching this and reading about it can leave you feeling a little overwhelmed.
Wow, why is this so complicated? Why do these factors I have no control over influence things? What do you even do about it? I’m having a stress response reading about this!
I hear you. Isn’t it so frustrating that things that happen a long time ago still impact how our bodies response to stress today? But, as I heard Sharon McMahon say on Emily P. Freeman’s podcast last week, “Facts don’t care about your feelings”. If we’re going to make any headway in addressing the way stress drives hormonal imbalance, it’s important to acknowledge that there are things within our control, and outside our control. We can’t change the past and we can’t change our genetic make-up. We can change how we respond to our past, and we can choose how we interact with our present reality. Is any of that easy? Well, honestly? No. It’s hard work, and you’ll be traveling up stream. But I think it’s worth it.
The good news, is that because the whole system works together, when you start making changes that are good for one part of it, it’s going to help everything. This sort of holistic health approach is usually slower, but balancing out a system takes time. Depending on the confluence of factors you’re dealing with, supporting your HPA axis might look like a few tweaks, or it could look like throwing an entire arsenal of tools at the problem. In the next part of the series I’ll share a bit more about how that’s looked for me, along with some of my best ideas for supporting your body.
And, because I don’t want to leave you feeling frustrated or hopeless, here’s a printable list of FREE, mom-friendly, stress busting ideas for taking things down just a notch. None of these are going to fix your HPA axis, but every little thing you can do to tell your autonomic nervous system you’re safe, counts.
Thanks for sticking with me on this one! What questions does this leave you with? Did you have any lightbulb moments while you read it? Were you familiar with any of this material?
Next time we’ll talk about cholesterol, insulin resistance, carbohydrates, protein and more. I’ll also share some favorite supplements that have been key in supporting me during some stressful times. A quick reminder that I am not a doctor and this is not medical advice. If we were friends in real life, these are the things I have a hard time shutting up about, so just imagine that we’re in my living room and I’m your nerdy friend who sometimes likes to read Pubmed journals for fun.
Hantsoo, Liisa, Kathleen M. Jagodnik, Andrew M. Novick, Ritika Baweja, Teresa Lanza di Scalea, Aysegul Ozerdem, Erin C. McGlade, et al. “The Role of the Hypothalamic-Pituitary-Adrenal Axis in Depression across the Female Reproductive Lifecycle: Current Knowledge and Future Directions.” Frontiers in Endocrinology 14 (December 12, 2023): 1295261. https://doi.org/10.3389/fendo.2023.1295261.
Just for clarity: the autonomic nervous system includes both the sympathetic (“fight flight”) and the parasympathetic (“rest digest”) response.
M.D, Bessel van der Kolk. The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma. Reprint edition. Penguin Books, 2015. p. 60-61
Stephens, Mary Ann C., and Gary Wand. “Stress and the HPA Axis.” Alcohol Research : Current Reviews 34, no. 4 (2012): 468–83. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3860380/.
Ibid
Hantsoo et al., “The Role of the Hypothalamic-Pituitary-Adrenal Axis in Depression across the Female Reproductive Lifecycle.”
To be honest, I don’t know if most MDs would even go here. This is probably something you’re going to have the best luck with if you pursue functional medicine.
Brighten, Dr Jolene. “What Is HPA Axis Dysfunction + 7 Steps to Heal HPA-D,” November 20, 2023. https://drbrighten.com/hpa-axis-adrenal-fatigue-and-dhea/.
Stephens and Wand, “Stress and the HPA Axis.”
Briden, Lara. “Have You Lost Your Period to a Low Carb or Keto Diet?,” December 1, 2015. https://www.larabriden.com/have-you-lost-your-period-to-a-low-carb-diet/.
Brighten, “What Is HPA Axis Dysfunction + 7 Steps to Heal HPA-D.”
Hantsoo et al., “The Role of the Hypothalamic-Pituitary-Adrenal Axis in Depression across the Female Reproductive Lifecycle.”
Hantsoo et al., “The Role of the Hypothalamic-Pituitary-Adrenal Axis in Depression across the Female Reproductive Lifecycle.”
If you are dragging yourself out of bed each morning, and can’t ever really wake up, it’s a sign that cortisol is probably doing something weird.
Ibid
Ibid
Ibid
“Hormone Series Part 2: Cortisol and Progesterone Levels & Symptoms | The Fork Clinic.” Accessed March 25, 2024. https://www.theforkclinic.com/post/hormone-series-cortisol-and-progesterone.
Low thyroid, perimenopause, insulin resistance, high prolactin (breastfeeding!!!), and inflammation can all mess with progesterone as well
Brighten, “What Is HPA Axis Dysfunction + 7 Steps to Heal HPA-D.”
This was such a good summary and that PDF! So many great ideas.
I’m curious about your comment that we can control our response to the past. Do you primarily have therapy/ therapeutic means in mind?
This is so good! There are so many internet influencers out here selling CBD tinctures and somatic exercise programs claiming to heal trauma and it absolutely boils my blood. First of all, it’s unethical and second of all it’s dangerous. Then add in the idea that healing means adding more to an already full life, adding a laundry list of self care practices that actually increase stress and it makes for a really disgusting soup of bad advice.