What 'Feeling Overwhelmed' Is Actually Telling You About Your Brain

You are sitting at your desk. There is a list in front of you. You know what needs to be done. And yet — nothing happens. You read the same line three times. You open a tab and forget why. You feel a dull weight behind your eyes, a tension in your shoulders, a faint sense of dread that has no single, clean address.

That is not laziness. That is feeling overwhelmed — a measurable neurological event, not a character flaw.

According to the Health and Safety Executive's Labour Force Survey for 2024/25, an estimated 964,000 workers in the UK were suffering from work-related stress, depression or anxiety — a record high, up from 776,000 the year before. That is the figure specific to stress-related conditions, not the wider work-related ill health total, which is larger and covers physical injury too. Feeling persistently overwhelmed is one of the most commonly reported precursor symptoms.

The Neuroscience Behind Feeling Overwhelmed

The prefrontal cortex (PFC) is the seat of executive function: planning, reasoning, decision-making, and emotional regulation. It is the part of your brain that makes you functional. It is also the part that goes quiet when you are overwhelmed.

The amygdala — deep in the brain's limbic system — is your threat-detection centre. Think of it as a smoke alarm bolted to your kitchen ceiling. A good smoke alarm cannot tell the difference between a house fire and a bit of burnt toast — it just goes off. Your amygdala has the same problem. It cannot reliably distinguish between a genuine threat and a packed inbox. Both register as danger. Both set off the same alarm: the HPA axis activates, cortisol floods the bloodstream, and your nervous system shifts into heightened alert.

Research published in Neuropsychopharmacology (2021) confirmed that the prefrontal cortex normally exerts inhibitory control over the amygdala — in effect, it is meant to be the calm adult who checks the toast isn't actually a fire and switches the alarm off. Under sustained stress, that regulation weakens. The amygdala becomes hyperactive; the PFC becomes hypoactive. The alarm keeps ringing, and nobody comes to check the toast. The reactive brain runs the show while the planning brain steps back.

A 2023 review in Frontiers in Endocrinology found negative correlations between elevated cortisol and cognitive functioning — including working memory and executive function. Higher cortisol measurably reduces the brain's capacity for complex thought. The longer you stay overwhelmed, the harder it becomes to think your way out of it. Stress impairs the very systems you need to manage stress.

Overwhelmed vs Overstimulated: Why the Distinction Matters

These terms describe different states with different causes and different solutions.

Overwhelm is internal cognitive and emotional overload. It builds over time from accumulation: too many responsibilities, too many unresolved decisions, too many competing demands on mental bandwidth.

Overstimulation is external sensory overload — noise, light, competing conversations, constant digital interruptions. It tends to happen faster and often resolves when the sensory environment changes.

Trying to reduce your task list when you are overstimulated will not help much. Retreating to a quiet room when seventeen unresolved commitments are spinning in your working memory brings momentary relief, but the overwhelm returns the moment you check your phone. They require different responses. Conflating them wastes recovery time.

Four Signals Your Brain Is Sending

1. Mental paralysis. You know you need to act. You cannot seem to start. When everything feels equally urgent, the brain struggles to initiate action on any of it. This is not procrastination — it is a bottleneck in task prioritisation circuitry. The queue is too long and nothing has been ranked.

2. Disproportionate irritability. Small frustrations provoke outsized reactions. When the prefrontal cortex is under-resourced, its ability to modulate the amygdala's responses is reduced. The emotional brakes become less responsive. Regulatory capacity is depleted.

3. Decision fatigue. Simple choices feel disproportionately draining across the day. Baumeister and Vohs established through multiple studies that sustained decision-making depletes the cognitive resources available for subsequent choices. In overwhelm, this process accelerates.

4. Physical heaviness. Cortisol has systemic physical effects — disrupted sleep, muscular tension from sustained sympathetic activation, fatigue from chronic stress-response demand. This is not tiredness from activity. It is depletion from sustained internal pressure.

These are not character failings. They are data. The brain, under excessive load, flags that something needs to change.

The Cognitive Architecture of Overwhelm

Working memory — the brain's system for holding and manipulating information in the moment — operates under strict capacity constraints. George Miller's foundational research established that the prefrontal cortex can hold only a small number of information chunks at once. When that capacity is exceeded, the system does not just slow down — it begins to fail at basic prioritisation and sequencing tasks.

Think about your phone battery. Every app you leave running in the background — even ones you are not looking at — quietly drains power. Close them, and the battery lasts longer. Your working memory works the same way. The Zeigarnik effect describes how incomplete tasks stay cognitively active in the background, occupying working memory even when you are not actively thinking about them. Each unresolved commitment — the email you have not sent, the decision you have deferred, the conversation you are avoiding — is an app you never closed. It keeps running, keeps drawing on the same finite battery your actual work needs. The experience of overwhelm is, in part, the subjective experience of that battery being spent before you have started the day's real demands.

Why Structured Planning Reduces Overwhelm

Working memory has limited capacity. Tasks and commitments that exist only as unstructured mental noise occupy cognitive space continuously — the brain keeps returning to them because they remain unresolved. This is the Zeigarnik effect again: open loops stay active until closed.

Externalising demands onto a structured planning tool closes those loops, the same way force-quitting an app actually stops it draining your battery, rather than just minimising it. It signals to the brain that information has been captured and ranked — releasing working memory from holding it. Cognitive load drops. The stress response begins to regulate.

This is what the OCCO London planning tools are built to do. The Priority Pad, Could Do Pad, and Morning Mindset Journal each offload cognitive demands from working memory onto the page — not to add complexity, but to reduce the mental noise that sustains overwhelm. Structure is not discipline for its own sake. It is a practical intervention in a neurological problem.

Browse the full OCCO London range at occolondon.co.uk/collections/productivity-tools.

When to Take It More Seriously

If feelings of overwhelm are persistent and significantly affecting your ability to function — rather than responding to specific high-pressure periods — this may indicate that anxiety, burnout, or ADHD is a contributing factor. Speak to your GP, who can assess what support is appropriate. In the UK, you can also self-refer for talking therapy via your local NHS talking therapies service at nhs.uk without needing a GP appointment in most areas.

Related Reading

• Mental Load: Why High Achievers Are Always Tired
• What Your Brain Fog Is Actually Trying to Tell You
• If You're Constantly Exhausted Despite Getting Things Done

Frequently Asked Questions

Why do I feel overwhelmed for no reason?

Overwhelm rarely appears without cause — the cause is often invisible rather than absent. Accumulated open loops, deferred decisions, sustained low-level stress, and poor sleep all increase the cognitive load your brain is carrying before you sit down to work. When that background load is already high, even minor additional demands can tip the system into overwhelm. The trigger is small; the underlying pressure was already there.

What does it mean when you're constantly overwhelmed?

Persistent overwhelm — rather than overwhelm that responds to specific high-pressure periods — typically indicates that the underlying cognitive load has become structural rather than situational. This can be a sign of burnout, anxiety, ADHD, or simply a chronic mismatch between demands and capacity. If reducing your workload temporarily does not relieve the feeling, it is worth speaking to a GP to rule out clinical contributors.

How do you calm down when you feel overwhelmed?

The most reliable short-term intervention is a slow, extended exhale — breathing out for longer than you breathe in activates the parasympathetic nervous system and reduces the cortisol response within a few minutes. The most reliable medium-term intervention is externalising: writing down everything you are currently holding, ranking what actually matters today, and releasing the rest. This directly addresses the working memory overload driving the overwhelm.

Is feeling overwhelmed a sign of anxiety?

They overlap but are not the same. Overwhelm is a cognitive state — too much in working memory relative to capacity. Anxiety is a nervous system state — sustained activation of the threat-response system. High cognitive load can trigger anxiety, and anxiety amplifies the experience of overwhelm, so they often co-occur. If feelings of overwhelm are accompanied by persistent worry, physical tension, or difficulty switching off even when demands are reduced, a GP assessment is worthwhile.