The 3 stages of stress your body goes through – and how to break the cycle

When you experience stress – whether positive or negative, physical or emotional – your body doesn't just react in the moment. It moves through a series of distinct physiological stages designed to help you survive. This process is known as General Adaptation Syndrome (GAS), a framework first described by endocrinologist Hans Selye in the 1930s that remains one of the most relevant models for understanding how chronic stress affects the body.

There are three stages: alarm, resistance, and exhaustion. Knowing where you are in this cycle is one of the most powerful things you can do for your long-term health.

Stage 1 – Alarm: the fight or flight response (cortisol and adrenaline spike)

The alarm stage is your body's immediate, automatic response to a perceived threat. The moment your brain registers stress, your sympathetic nervous system activates and signals the adrenal glands to flood the body with stress hormones – primarily adrenaline, which mobilises energy fast, and cortisol, which sustains that response over time.

The physical effects are immediate and unmistakable: elevated heart rate, rising blood pressure, faster breathing, muscle tension, and heightened alertness. This is your body doing exactly what it evolved to do – preparing you to respond to danger.

In short bursts, this response is not only normal but beneficial. It sharpens focus, boosts performance, and can even support immune function temporarily. The problem arises when the alarm never fully turns off.

Stage 2 – Resistance: adapting to the pressure (cortisol normalises, but vigilance remains)

Once the immediate stressor passes, the parasympathetic nervous system steps in – activating the rest and digest response, lowering heart rate, and signalling the body to begin recovering. Cortisol levels start to normalise.

But here is where most people in modern life get stuck.

If the source of stress is not resolved – or if new stressors keep arriving before the body has fully recovered – the system never fully resets. Instead, the body adapts to the elevated stress load and builds up a tolerance to coexist with it. Outwardly, you might seem fine. Inwardly, your nervous system is still running on high alert, quietly draining your resources.

This is the stage where many people operate for months or even years without realising it. The warning signs are subtle: difficulty switching off in the evenings, waking at 3am, relying on caffeine more than you used to, feeling reactive or irritable in situations that didn't used to bother you.

Stage 3 – Exhaustion: when the body can no longer compensate (cortisol drops – sometimes critically low)

When resistance goes on too long without genuine recovery, the body reaches its limit. Stress hormone reserves become depleted, the immune system weakens, and the body loses its capacity to adapt. This is burnout – not a state of mind, but a genuine physiological collapse.

The symptoms at this stage are wide-ranging and can affect virtually every system in the body:

• Persistent fatigue that sleep doesn't resolve
• Mood disruption: low motivation, irritability, low-grade anxiety or depression
• Cognitive fog – difficulty concentrating or retaining information
• Disrupted hunger cues and increased fat storage, particularly around the abdomen
• Elevated blood pressure and cholesterol
• Joint and muscle aches
• Digestive complaints: bloating, reflux, cramps, nausea
• Hormonal disruption: absent or irregular cycles, low libido, reduced sperm production in men

What makes stage 3 particularly challenging is that cortisol – the very hormone meant to help you cope – is now depleted. The body has been running on empty for so long that it can no longer mount a stress response at all.

Breaking the cycle: what actually helps

The ability to move fluidly between fight-or-flight and rest-and-digest is not a luxury – it is a biological necessity. Without genuine recovery windows, the body cannot repair itself.

The challenge is that modern life keeps the alarm system activated almost continuously. Emails, notifications, packed schedules, and financial pressure are processed by the nervous system in much the same way a physical threat would have been for our ancestors. The brain doesn't distinguish between a deadline and a predator – it responds to perception of threat, and our thresholds for that have never been lower.

Some of the most evidence-supported ways to shift out of sympathetic dominance:

• Breathwork – slow, diaphragmatic breathing is one of the fastest ways to activate the parasympathetic nervous system
• Movement – particularly walking in nature, yoga, or any rhythmic, non-competitive exercise
• Sleep hygiene – cortisol follows a diurnal rhythm; disrupted sleep perpetuates the cycle
• Identifying your stressors – not to eliminate them all, but to understand which ones are driving the highest nervous system load
• Nutrition – blood sugar dysregulation is a significant stressor to the adrenal system; stabilising it through food can meaningfully reduce baseline cortisol

Stress is not something to simply push through or manage. It is a physiological signal worth listening to – and the earlier in the cycle you respond, the easier it is to course-correct.

To go deeper into understanding your own stress response and build a personalised toolkit, explore our Stress Fundamentals course.