Menopause & Perimenopause — why your body can feel like it's working against you

You're in your 40s and suddenly your body doesn't feel like your own. One minute you're fine, the next a wave of heat rises up your chest and neck and you're pulling off your jumper in a cold January meeting. Your sleep is broken, your patience is shorter, and the brain fog makes you lose your words mid sentence.

Menopause and perimenopause are not simply the end of your periods, for many women the symptoms start years earlier, often in your 40s, long before your cycle changes. It is a fundamental shift in your nervous system and hormone chemistry, and understanding what's actually happening in your body is the first step to feeling like yourself again.

Oestrogen does far more than regulate your cycle. It helps calm your nervous system, supports the neurotransmitters that stabilise your mood and sleep, and keeps your temperature control finely tuned. As oestrogen and progesterone decline through perimenopause and menopause, your body loses much of that natural buffering, so hot flushes, night sweats, brain fog, low mood and racing thoughts are often your nervous system reacting to a chemistry it no longer recognises.

Declining progesterone can also mean your breath becomes shallower and more chest based, which keeps your body locked in fight or flight rather than settling into rest, and fuels the stress response even further.

If your nervous system was already running in a stressed, hypervigilant state before perimenopause began, this drop in progesterone and oestrogen tends to make everything feel worse. Cortisol regulation becomes less efficient, blood sugar swings become more noticeable, and symptoms like anxiety, fatigue and gut changes that you managed fine in your 30s can suddenly feel unmanageable.

This is why two women in their 40s can go through the same hormonal changes and have completely different experiences, it depends on how well your nervous system was coping to begin with.

Menopause and perimenopause symptoms feed into nervous system dysregulation in a cycle, shallow breathing and poor sleep raise stress hormones, which worsens hot flushes and mood, which disrupts sleep further. Breaking that cycle means working with your body's chemistry rather than against it, calming the nervous system, stabilising blood sugar, and giving your body the support it needs through this transition.