The HPA Axis: Why Stress Is a Physical Condition, Not a Mood

By Tina Chagoury, Clinical Dietitian · 5 min read · 2026-09-07

When I say stress is affecting your hormones, this is the actual pathway. Stress is an inflammatory, physical state, not a feeling.

When I tell a woman that stress is affecting her hormones, she often hears it as a soft statement. Something close to "try to relax."

It is not. There is a specific physical pathway involved, and it has a name: the HPA axis.

What the letters mean

HPA stands for hypothalamic, pituitary, adrenal.

The hypothalamus and the pituitary are structures in the brain. The adrenal glands sit on top of your kidneys.

These three communicate constantly, in a loop. The brain signals the adrenal glands, the adrenal glands release cortisol, and cortisol feeds back to the brain to regulate the response.

That loop is your stress response system.

Why it connects to everything else

The hormonal system, properly called the endocrine system, and the nervous system are closely connected. Both are closely connected to the immune system.

Which means the HPA axis is not a separate department dealing with feelings. It is wired into:

• Blood sugar regulation. Cortisol raises glucose. That is its job in an emergency.
• Where fat is stored, favouring the abdomen when cortisol is chronically elevated.
• Fluid balance, because cortisol influences aldosterone, which governs sodium and water retention.
• Reproductive hormones, because sustained stress signals that this is not a good time to ovulate.
• Immune function and inflammation.
• Sleep, which is governed by the cortisol rhythm.
• Thyroid function.

What chronic activation looks like

The system is designed for short bursts. Something threatens you, cortisol rises, you deal with it, cortisol falls.

What it is not designed for is a state that never ends. Work, children, waking at five, poor sleep, undereating, overtraining, an underlying health problem.

Under sustained activation the body does something entirely rational. It shuts down every function it considers non essential in order to survive the day. Fat loss is non essential. Fertility is non essential. Ovulation is non essential.

This is what nervous system dysregulation actually means, and it is why a woman can do everything correctly on paper and see nothing change.

The line I want to be clear about

Stress is not a mood. It is a physiological, inflammatory state that produces measurable changes in blood sugar, fat storage, immune activity and hormone production.

Telling a woman in that state to eat less and train harder pushes her further into the condition causing the problem.

What actually helps

The interventions here are unglamorous, and they are also free.

• Sleep at consistent times, including weekends. This regulates the cortisol rhythm more effectively than anything else.
• Morning light, early, in your eyes.
• Eat enough. Undereating is itself a stressor.
• Stop training on a tired, sleepless body. Rest and recovery matter more than the session you forced yourself through.
• Breathing practices. Box breathing, done briefly and regularly, is a genuine intervention rather than a nice idea.
• Walking. Particularly outdoors, particularly after meals.

What women most often forget is that the most essential things for their hormones are the ones that cost nothing: sleep, hydration, food choices, stability, consistency and stress management.

Listing them makes them sound easy. In practice they are not. But if you are going to put effort somewhere, put it here.

This article is nutrition education, not medical advice.

Tina Chagoury is a licensed clinical dietitian specialising in women's hormonal health, and the creator of the Hormone Reset Method™. Learn more and start here.