There’s a process that occurs in our body called the HPA Axis (Hypothalamic Pituitary Adrenal Axis) which plays a part in regulating our body’s energy and stress response. I learnt a little about this at the blood chemistry analysis course I was at a few weeks ago. Why it’s so relevant to your body composition results and training performance is that it’s all interconnected from how you eat, train, rest, recover and manage stress.
If it seems to be that you’re doing everything right on paper; eating healthy and training regularly but you’re still not having the energy that you want or the training results (fat loss, lean muscle building, increased performance) to show for it this article will help explain why and what to do about it.
Here’s a very brief and simple summary of how the HPA Axis works:

The hypothalamus (H) is a small part of your brain that links your nervous system to your endocrine system via your pituitary (P). When you get stressed your hypothalamus will recognise that signal and produce a hormone to send to your pituitary which then produces a stimulating hormone to send to your adrenal glands (A) to start producing cortisol.
The HPA Axis doesn’t primarily regulate stress but also helps to regulate growth hormone, sex hormones and thyroid.

If training results are important to you, you want these pathways working bang on.
For healthy metabolism and energy (Thyroid – HPT Axis):

- Hypothalamus releases TRH (Thyroid Releasing Hormone) into the bloodstream
- TRH stimulates your Pituitary Gland to release TSH (Thyroid Stimulating Hormone) into the bloodstream
- TSH binds to your Thyroid Gland to produce T4 and T3
- Active form T3 stimulates cells in your body to burn energy (carbs and fats)
For a healthy stress response (Adrenals – HPA Axis):

- Hypothalamus releases CRH (Corticotropin-releasing hormone) into the bloodstream
- CRH stimulates your Pituitary Gland to release ACTH (Adrenocorticotropic hormone) into the bloodstream
- ACTH activates your Adrenal Glands to release Cortisol
- Cortisol raises your blood sugar to get ready for either “Fight or Flight”
- For fat loss cortisol produces adrenaline and adrenaline releases free fatty acids from fat cells making them ready to be burned as energy
Both systems work on a positive feedback loop:
For both your Thyroid and Adrenal Glands once there’s enough T4/T3 and Cortisol in your bloodstream that will send a signal to your pituitary gland to stop producing more TSH or ACTH, that’s a positive feedback loop.
Once there’s enough hormones in our body to make it do what it needs to do, it doesn’t need to produce any more of it because too much of it in our bloodstream can be toxic. Naturally our body is very smart at regulating itself, in this case it’s the hypothalamus that’s continually regulating hormone levels in our body.
Problems occur when there’s a negative feedback loop:
If your body is producing too much of the hormones (e.g. T4, T3, and cortisol) at some point your hypothalamus and pituitary will become less sensitive at receiving the positive feedback to regulate your body. Think of this as similar to insulin sensitivity and insulin resistance.
Also what can occur is that your Thyroid and Adrenal Glands can become less effective at receiving the hormones sent by your pituitary (TSH and ACTH), this is because if you have high levels of inflammation in your body due to stress your immune system is also going to be producing certain molecules which bind to the same receptor sites as what TSH and ACTH would at both your Thyroid and Adrenal Glands.

Your pituitary could still be producing hormones TSH and ACTH but because you’re highly stressed TSH and ACTH can’t attach onto their receptor sites at the glands to stimulate both your Thyroid and Adrenals to produce energy.
When people say they have Adrenal Fatigue it’s not because their adrenal glands aren’t working and need to be “nourished”, a better term would be Adrenal Insufficiency where TSH can’t bind to the Adrenal Glands due to inflammation caused by stress. To solve this you would need to help clear the pathway so that TSH is binding to its receptor site at the Adrenal Gland.
It comes back down to balancing your hormones and managing your stress:
You don’t want to produce too many hormones as over time your hypothalamus and pituitary can become more resistant to receiving it’s feedback. You don’t want to have too much inflammation and stress either as their molecules can block your hormones from attaching to their end organs to do it’s work.
The 4 Types of Stress You Need to Manage for HPA Axis Function:
1. Inflammation (Bacterial)
Inflammation requires your immune system to release certain molecules to deal with the stress. Unfortunately they also attach onto the same receptor sites at our end our organs as our stimulating hormones do.
Our end organ stimulating hormones (e.g. TSH and ACTH) can’t attach onto its receptor site because immune system molecules are attached to it instead.
Plenty of reasons as to how inflammation can occur:
- Poor food choices (additives, colourings and sensitivities)
- Lifestyle choices (smoking and excessive drinking)
- Viruses (sickness)
- Overexposure to man made chemicals and toxins
- Chronic stress
- Pathogens
- Overtraining and under-eating
By reducing bacterial inflammation you’re reducing the amount of immune system molecules circulating around your body that have the potential to block the pathway between your end organs and your stimulating hormones.
2. Blood Sugar Management
Say you have cereal and OJ for breakfast which raises your blood sugar and than an hour later your blood sugar comes crashing back down. You don’t have time to eat until lunch break. What happens during this time is that your body will recognise that your body is under stress (from low blood sugar) which then calls upon your Adrenal Glands to release cortisol which raises your blood sugar to deal with the stress (hunger) until lunch break.
If this happens once in a blue moon, it’s not a big deal as your body can handle it.
However this happens way too often in this day in age either unconsciously or consciously from poor food choices (refined sugars), skipping meals, not eating enough or not having the right mix of protein, carbs, fats and fiber in meals to manage blood sugar.
If your blood sugar is regularly bouncing up and down, you’re creating more work for your adrenals to release cortisol which in the long run dysregulates your HPA Axis function.
How to optimally manage your blood sugar:
- Have a high protein and fat breakfast
- Implement carb timing (Have carbs when you need it or deserve it)
- Ensure you’re assimilating nutrients properly (If you have gut issues nutrients can leak through your digestive system and into your bloodstream which then calls upon your immune system to have to deal with that stress thus leaving you blood sugar always being more elevated than usual)
- Eat real food that you have to chew instead of liquids
- Lower GI load of a meal by mixing macronutrients (Protein, Fats and Carbs) – it’s slower to digest in comparison to just having a carb source on it’s on own
- Have more Apple Cider Vinegar as it’s been shown to lower your blood sugar and improves insulin sensitivity before meals by up to 30%
- Take steps to repair gut health if you think it’s been compromised
- Ensure you’re eating enough food (You can use this calculator here), select maintenance and if you need to eat more or less always make small adjustments rather than big ones. Some people don’t even eat enough to cover their BMR (Basal Metabolic Rate), calories needed in a day to function to without moving
3. Circadian Rhythms
Many of the hormones in our body maintain roughly a 24-hour rhythm controlled by the suprachiasmatic nucleus (SCN) which is located in the hypothalamus. As you might already know we would naturally produce more cortisol first thing in the morning when we wake and then produce less of it towards the afternoon and evening. In healthy individuals with normal circadian rhythms the evening and during sleep the SCN would signal to pineal gland to release more recovery hormones such as melatonin and growth hormone.

At times you’re exposed to direct sunlight your pineal gland starts producing melatonin which is then released in the evening to help you wind down and sleep.
By regulating your circadian rhythm you’re regulating your cortisol output as well as other hormones helping the HPA Axis maintain its sensitivity to feedback.
Producing less cortisol in the afternoon and evening would help promote relaxation, sleep and the overall recovery of our body. Producing more cortisol during this time and it makes it harder for our body to recover from dealing with stress.
How to regulate your circadian rhythm:
- Get up with sunrise (Don’t sleep in)
- Get 15 minutes of direct sunlight/day (Walk outside)
- Train in the morning if you can
- Do all stressful activities first thing (Eat the frog)
- If working night shift book in a Holiday or maximise your normal days by getting as much sunlight and normal sleeping patterns as possible
4. Perceived Stress
Perceives stress is mental, back in the day of our ancestors all they had to be stressed about was food (when and where they could eat) and during times of danger (for e.g. coming across a lion – fight or flight).
Today we have an enormous amount of perceived stress.
- Work deadlines
- Money
- Bills
- Getting your kids ready for school
- Which suburb you’re going to buy your next house in?
- Why is Mary wearing the same shoes as you today?
- Why hasn’t your Instagram account hit 1000 followers yet?
With perceived stress your hypothalamus still recognises it the same as physical stress and it creates the same stress response in your body. Some of it is legitimate perceived stress and it is what it is, we all have responsibilities and deadlines to meet.
We can’t all live like caveman and cavewoman and expect to live a good life, it’s not possible because we need some level of resources.
If you can better manage your perceives stress you’re going to better manage your stress response to when you actually need it.
Here’s how:
- Limit your stress output only to things that matter
- Gratitude log (What you appreciate, appreciates)
- Cold therapy (Improves stress tolerance and resilience)
- Meditation (Promotes GABA production in brain)
- Implement a free day (Play sport, games, Netflix, relax)
- Achieve something faster? Get a mentor (Nearly everything’s been done before)
By focusing on reducing and managing 4-types of stress (Inflammation, blood sugar, circadian rhythm and perceived stress) that contribute to HPA Axis function you’re going to better be able to produce the hormonal output that’s required for body composition and training results.
The better you can naturally produce thyroid hormones from your adrenal glands the better your metabolism is going to be. The better you can naturally produce cortisol during training the more adrenaline you’re going to have during training and the more free fatty acids you’re going to release ready for fat burning.
Train hard, optimise your recovery.