The Hypothalamic-Pituitary-Adrenal axis, or HPA axis is one of your body’s most vital hormonal communication networks. The HPA axis is the communication between your hypothalamus, your pituitary, and your adrenal glands. It’s a negative feedback system. So when your hypothalamus perceives that your adrenals are not producing enough cortisol, your hypothalamus produces cortico releasing hormone (CRH).
That stimulates your pituitary gland to produce adrenocorticotrophic hormone (ACTH), which is the stimulus hormone that tells your adrenal glands to produce cortisol. When you make too much cortisol, your hypothalamus stops production of CRH. Like a seesaw, your HPA hormonal axis is a negative feedback system.
So what does the HPA axis do?
Your HPA axis coordinates your stress response. You don’t necessarily have to experience a major stressor to have a stress response or a fight or flight reaction. Your HPA axis is activates when you exercise, get startled by a loud sound, or even when your blood sugar drops.
Your HPA axis also follows a circadian rhythm. As soon as the sun comes up in the morning, your melatonin level drops. Your blood sugar is low because you’ve been fasting all night. The rising sun and your low blood sugar activates your HPA axis. Your hypothalamus tells your adrenal glands to produce cortisol. Cortisol then releases stored sugar from your liver and muscles. All so your hypothalamus can break its fast and get to work.
Cortisol’s job is to release stored sugar to fuel your body as part of the stress response. You make the most cortisol from 8 am to 2 pm. Then, your cortisol levels fall naturally as your HPA axis rests. At about 5 pm, your hypothalamus activates your adrenals through the HPA axis, and you get another surge of cortisol. You get a second wind. About three hours after dusk when melatonin levels start to rise, your HPA axis turns off so that you can go to sleep. You don’t want to produce cortisol at night because it will keep you up.
So why is the HPA Axis important?
Your HPA axis is vital to your survival. When the communication is disturbed between your hypothalamus in your brain, your pituitary gland, and your adrenal glands, you can become ill. Your pituitary gland acts as the middle manager. When your HPA axis is over-activated from chronic stress or disease, communication fails and it affects your adrenal function.
As a result, your cortisol production becomes poor for your body’s needs. Cortisol is a glucocorticosteroid, which means it’s a hormone that controls glucose metabolism. Your adrenals produce another hormone in response to how much cortisol you need, called DHEA. This helps you metabolize protein and fat. Without adequate cortisol and DHEA, you will have trouble metabolizing carbohydrates, protein, and fat. You will also not be able to build tissues properly or have enough energy in your system.
If your HPA axis gets disturbed, especially if your hypothalamus becomes damaged, your adrenal function is going to be affected.
Let’s talk about your HPA hormonal axis and stress. The stress response is one of the most well-researched areas of hypothalamic-pituitary communication. When you perceive stress, your stress response is the same. When you perceive stress, it doesn’t really matter if you’re late for work, you forgot to pay a bill, you’re in an accident, or you’re being chased by a tiger.
The first thing that happens is you get an autonomic nervous system response. Your hypothalamus is intimately connected to your autonomic nervous system. Your autonomic nervous system stimulates your adrenals to produce adrenaline. Adrenaline gets your heart rate and blood pressure up so you can start running away from the danger. Adrenaline triggers your hypothalamus, which notes if your blood sugar is adequate to fuel your stress response.
If your blood sugar is not adequate, your hypothalamus produces cortico releasing hormone. Which then stimulates your pituitary gland to produce ACTH, which stimulates your adrenals to produce cortisol. Cortisol then stimulates your pancreas to release glucagon. Glucagon is the opposite of insulin. While insulin gets sugar into cells, glucagon gets sugar out of cells. Glucagon releases sugar stored in your liver and muscles into the bloodstream so that you have enough fuel to deal with the stressor.
In response to how much cortisol is needed, your adrenals also produce DHEA. Where cortisol is a catabolic hormone that breaks down tissues, DHEA builds tissues. DHEA helps to repair any damage from the fight or flight response.
Also in response to the stressor, your adrenal glands produce aldosterone in order to get your blood pressure up. Aldosterone is controlled partially by the adrenaline surge, and partially by the lack of hypothalamic vasopressin. Aldosterone tells your kidneys to hold onto more salt and water, and release potassium in order to maintain your blood pressure so you can get away from danger.
The stress response is very complex and totally dependent on a functioning HPA axis. If the HPA axis doesn’t function properly, it means you’re not making enough hypothalamic cortico releasing hormone. And you’re not making enough stimulating ACTH production from the pituitary gland. Therefore, you’re not going to have enough cortisol production. Your HPA axis can get overworked, meaning if you’re under stress for a long period of time, your HPA axis becomes desensitized. This leads to low functioning of your adrenals. Research shows that in brain MRIs of people under chronic stress, the part of their hypothalamus that orchestrates the HPA axis shrinks.
How do you keep your HPA hormonal axis healthy?
You want to keep the HPA axis activated by doing a few things:
First, make sure you’re sleeping in the dark and that you’re getting up with the light.
Getting adequate sleep in the dark helps your adrenals to calm down, and turns your HPA axis down so your hypothalamus can rest. Then, getting up with sunlight allows your HPA axis to follow a natural, healthy circadian rhythm by turning on again.
Second, try using stress reduction techniques like meditation, yoga, or deep breathing to help calm your HPA axis.
If you have a tendency towards a very hyper-reactive stress response and get very stressed easily, you’re going to wear out your HPA axis. Learning to control your stress response can spare your HPA axis. I particularly like deep breathing exercises, so I’ve developed a great CALM meditation that uses scent and sound to train your body to stimulate your parasympathetic nervous system to produce GABA, which will turn down your sympathetic nervous system’s excitatory response that’s causing you to over-activate your HPA axis. You can get access to my CALM meditation right here.
The third way to help your HPA axis stay healthy is to support your hypothalamus nutraceutically.
I recommend Genesis Gold®, which has been shown clinically to support healthy adrenal function, as well as to calm the stress response from an over-activated HPA axis. Genesis Gold® supports healthy hypothalamic function, which allows your HPA axis to communicate effectively.
Healing your HPA axis does take time. Although most people will notice a diminished stress response within the first month of using Genesis Gold®, it usually takes 90 days to heal your hypothalamus and the HPA axis completely. If you have any questions regarding the HPA axis, please join us in our Hormone Support Group. You’ll get access by signing up for our free Hormone Reboot Training.
On the Interactions of the Hypothalamic-Pituitary-Adrenal (HPA) Axis and Sleep: Normal HPA Axis Activity and Circadian Rhythm, Exemplary Sleep Disorders, The role of the hypothalamic-pituitary-adrenal axis in neuroendocrine responses to stress.
*Statements not reviewed by the FDA.