Running on Empty

There are days when everything feels slightly sharper than it should, when minor inconveniences land harder than expected and concentration requires more effort than it once did. The reaction can seem disproportionate to the situation, which makes it easy to assume that something is wrong with your patience or resilience.

Sometimes the trigger is not the situation at all but the timing of your last meal.

When food intake is delayed, skipped or inconsistent, blood sugar falls and the nervous system compensates by releasing adrenaline and cortisol to raise it. That response restores alertness quickly, but it does so by keeping the body in a more activated state. In your thirties and forties, when hormonal buffering begins to narrow, that compensatory surge becomes more pronounced.

For some women, that surge feels manageable. For others, particularly those with variations in genes such as ADRB2 or COMT that influence how the body responds to stress hormones, the effect can feel stronger or last longer than expected.

At one stage, that chemistry may have felt like sharpness and edge, creating momentum that carried you through long days. Over time, and particularly as sleep drifts and ovulation becomes less consistent, that same surge becomes harder to buffer.

For many women who are used to holding a great deal, inconsistent eating is not a deliberate choice but a by-product of cognitive load. Meals are postponed because something else feels more urgent and hunger signals are overridden because there is a task to finish, a child to collect or a message to send.

At one stage, that override carried little immediate cost because adrenaline filled the gap and cortisol restored focus, allowing the system to keep moving.

As the nervous system becomes less tolerant of repeated adrenaline surges, that pattern becomes more visible. Delayed fuel increases reliance on stress chemistry, and stress chemistry keeps the body in a more activated state. The line between hunger and irritability blurs and minor inconveniences can trigger responses that feel disproportionate to the event itself.

Over time, this creates a loop. Blood sugar dips prompt adrenaline release and adrenaline suppresses appetite further. Meals are delayed again and recovery slows.

In recent years, many women have experimented with extended fasting windows or reducing carbohydrate intake in pursuit of metabolic flexibility. For some, this feels sustainable in certain phases of life. In others, particularly during the second half of the menstrual cycle, the physiological cost becomes more apparent.

The luteal phase, which begins after ovulation and continues until menstruation, is characterised by rising progesterone and a natural increase in metabolic demand. Basal body temperature rises slightly, and overall energy requirements increase, which makes the body more sensitive to blood sugar fluctuations.

Reducing carbohydrate intake or extending time between meals during this phase increases reliance on adrenaline and cortisol to maintain glucose. In the short term, that compensation preserves alertness. Over time, it amplifies reactivity and can disrupt sleep.

By the time menstruation begins, when oestrogen and progesterone both fall, the nervous system may already be operating on narrowed margins. What feels like emotional volatility or reduced resilience during the menstrual week is often the compounded effect of sleep drift, inconsistent fuel and repeated adrenaline surges in the days preceding it.

When blood sugar is unstable, the nervous system compensates by releasing adrenaline and cortisol more frequently. Over time, frequent adrenaline and cortisol surges leave the nervous system quicker to react and slower to return to baseline.

Regular meals reduce the frequency of those surges and allow the nervous system to remain steadier across the day.

In this phase, the basics matter more than they once did. Sleep regulates circadian timing and regular meals regulate glucose stability, and when both are protected the nervous system has fewer reasons to escalate and greater capacity to recover.

When blood sugar repeatedly relies on adrenaline for support, the body gradually learns to function on urgency.

This article is part of the Resilience Series.

Start here: When resilience changes.