Why Cognitive Load, Not Work Itself, Leaves You Drained

At 2:17 on a wet Tuesday in November, a client of mine whom I will call Marina turned her laptop toward me in a small coaching room near Old Street in London and said, with the flat anger of somebody who had already spent too much energy naming the problem, “I answered six emails, rescheduled a dentist appointment, paid an invoice, and now I feel as if I’ve done a twelve-hour shift.” Her calendar, at first glance, looked manageable. No marathon meetings, no emergency presentation, no executive crisis. What exhausted her was the invisible tax imposed by constant switching, unfinished decisions, and the effort of holding too many loose ends in mind at once, which is where cognitive load enters the picture with more force than most workplace advice admits.

When adults tell me they are tired of work, I often hear something more precise underneath the complaint. They are tired of the friction around work: the tab they must not forget to return to, the message they need to phrase carefully, the admin task with three possible next steps, the document that requires context they no longer have in active memory because the phone rang and Slack blinked and somebody asked for “a quick thing.” The body experiences that friction as fatigue, even when the output on paper looks modest, and the mismatch can make competent people feel faintly fraudulent, as though tiredness must be earned by something more visibly difficult.

Psychologists have been using the term “cognitive load” for decades, although it entered public conversation in a diluted form. John Sweller, the Australian educational psychologist who developed cognitive load theory in the late 1980s, was interested in learning and problem-solving, especially in the limits of working memory. The basic point remains stubbornly relevant outside classrooms: the mind can handle only so much novel, effortful processing at one time, and when a task demands too many simultaneous mental moves, performance degrades while strain rises. Daniel Kahneman, writing in “Attention and Effort” in 1973 and later in “Thinking, Fast and Slow,” described a related economy of mental effort, one in which attention functions less like a moral virtue than like a scarce budget that can be overspent before lunch.

What most productivity advice misses is that exhaustion does not map neatly onto hours worked or even objective difficulty. A surgeon may spend four hours in a demanding procedure and feel spent for reasons everybody around her understands; a project manager may spend the same four hours reopening the same spreadsheet, replying to pings, searching for a missing attachment, and deciding whether to start the budget note before the vendor call, and end up equally depleted with far less social permission to say so. The second kind of fatigue looks trivial from the outside because the tasks are small, but small tasks become punishing when they arrive fragmented, ambiguous, and poorly staged.

The hidden weight of unfinished decisions

One reason low-level tasks become so draining is that they rarely arrive as complete actions. They arrive as decision clusters. Reply to the email now or later; if later, where should it live; if it goes on the task list, what exactly is the task; if the task needs background, where do you store the link; if the request belongs in the calendar, how long will it take and what energy will it require. Roy Baumeister’s work on decision fatigue has been debated in its stronger claims, yet in coaching rooms the practical observation still holds: repeated micro-decisions wear people down, especially when there is no trusted structure for where decisions go once made.

Marina’s day offered a clean example. One message from finance asked whether she had approved a contractor payment. She had not, but she had half-reviewed the paperwork last Friday, which meant she needed to reconstruct her own thinking before she could act. Another message invited her to a meeting with no agenda, and she spent seven minutes trying to infer whether declining would be read as efficient or obstructive. By the time she opened the actual report she was meant to edit, she had already burned through a surprising amount of attentional fuel on interpretation, retrieval, and self-management rather than on the report itself.

There is a term from software design that clients sometimes find clarifying: context restoration. After an interruption, you do not return to a task at the point where you left it in some clean cinematic cut. You rebuild the scene. You remember what the numbers meant, what risk you had spotted, why paragraph three felt wrong, what you intended to ask legal, and whether the file in front of you is the current version. Gloria Mark, who has spent years studying attention and interruption at the University of California, Irvine, has shown how frequently knowledge workers switch activities and how long it can take to recover from interruptions; the time loss matters, but the more intimate cost is energetic, because restoration itself is work.

This is also where many neurodivergent adults recognise their own day more accurately than standard office language allows. The issue, in practice, is often not willingness or intelligence but the amount of mental scaffolding required to keep state, sequence, and intention intact across interruptions. When that scaffolding is built externally, through visible cues and reliable capture systems, people often function with striking steadiness. When it all has to be held internally, under conditions of noise and constant switching, fatigue arrives early and can look mysterious to colleagues who are only counting tasks completed.

Why easy tasks can feel harder than difficult ones

There is a paradox here that clients usually find relieving once they see it clearly. Difficult work, when it is coherent, can be less exhausting than easy work that is broken into jagged pieces. Writing a proposal for ninety uninterrupted minutes may demand concentration, but the mind settles into one set of rules, one objective, one frame of reference. Handling twenty “quick” items in the same ninety minutes often requires twenty different frames, twenty retrieval efforts, twenty moments of self-interruption, and a continuous negotiation over what matters now.

Barbara Tversky’s research on mind in motion, along with broader work in embodied cognition, helps explain why external structure matters so much. Human thinking is not a sealed, purely internal operation; it relies on movement, space, diagrams, notes, objects, and arrangement. When the environment supports sequence and memory, the brain offloads part of the burden. When the environment is cluttered, inconsistent, or hidden behind a maze of tabs and notifications, the burden returns to working memory, which is a poor warehouse and an expensive manager.

I saw this vividly with a client in Chicago, a senior operations lead I will call Daniel, whose employer had praised him for “thriving in ambiguity” right up to the month he started missing routine approvals. On paper, his role had become easier because he had delegated several large projects. In reality, his day had turned into a patchwork of low-clarity monitoring tasks: check a dashboard, skim a contract, answer a vendor query, review a draft, chase a signature, reopen the dashboard because the first look raised a question. “I’m not doing the hard part anymore,” he told me, staring at a legal pad filled with arrows and boxes. “I’m doing the remembering part, and the remembering part is killing me.”

That sentence gets closer to the truth than most performance reviews do. Knowledge work increasingly rewards people for maintaining state across fragmented systems, while talking as though the real job consists only of the visible deliverable. The proposal, the report, the analysis, the presentation—those are the artefacts. The fatigue often comes from all the hidden stitching required to produce them without losing the thread. Linda Stone, who coined the phrase “continuous partial attention” in the late 1990s, was describing a cultural condition before she was describing an individual failing, and that distinction matters because workers often blame themselves for attentional environments that would fray almost anybody.

Where the standard productivity fix breaks down

The usual advice, meanwhile, tends to arrive in forms that sound tidy and fail on contact with a real Tuesday. Make a list. Prioritise. Batch tasks. Turn off notifications. Time-block your day. None of this is wrong, exactly; I recommend versions of all of it. The problem appears one layer deeper, where the advice assumes that tasks are already well-defined units and that the worker can move them around like chess pieces. In practice, many tasks are still shapeless when they hit the list, and shapeless tasks create drag because the brain must repeatedly re-interpret them before action can begin.

A task that says “sort insurance” is not a task in any operational sense. It is a small cloud of uncertainty, and every time you read it your mind must reconstruct the missing edges: call whom, find which document, ask what question, expect how long. By contrast, “email insurer for replacement policy PDF; attach passport scan” has a fighting chance of becoming action because it reduces interpretation at the point of contact. This sounds pedestrian until you watch how much energy adults save when they stop asking working memory to perform clerical duties all day long.

The same principle applies to calendars, which are often treated as moral documents rather than cognitive supports. People pack them according to obligation and status, then wonder why the day collapses at 3 p.m. A calendar that ignores energy cost will routinely overestimate what can happen between meetings, because it counts minutes and ignores setup, recovery, and context restoration. When I ask clients to mark not only duration but cognitive weight—deep focus, shallow admin, social effort, ambiguity, error sensitivity—the week suddenly becomes legible in a way that colour-coding alone never achieved.

This is also why some adults feel disproportionately flattened by tasks that involve initiation rather than execution. Once underway, they can work with stamina and skill. Starting, however, demands orientation, sequencing, and tolerance for uncertainty, which are precisely the functions most exposed to cognitive overload. In “The Organized Mind,” Daniel Levitin makes a related point about the burden of excessive information and the value of external systems; the mind is excellent at some things, he argues, and notably poor at storing and sorting the thousands of reminders modern life asks it to carry unaided.

What helps when the day is already crowded

In coaching, the most useful interventions are rarely dramatic. They are architectural. A single trusted capture point reduces the low-grade panic of trying to remember where something lives. A task written in visible, behavioural language lowers the cost of starting. A calendar that protects one cognitively expensive block before noon often does more than a heroic plan for eight separate priorities. None of this is glamorous, and that may be why it works; the aim is to reduce avoidable load, not to produce the feeling of being virtuous about work.

Marina changed three things over six weeks, and the result was less spectacular than a transformation story but far more convincing. She stopped using her inbox as a holding pen for undecided work, because every reread was charging her twice. She rewrote tasks so that each one began with a verb and contained the first visible action. She also created what she called a “restart line” at the end of focused sessions, a single sentence left in the document or notebook that told her future self where to resume. “Check figures against April file; query row 48 before final edit” may not sound profound, she told me later, “but it means I don’t have to become a detective at 9 a.m.”

That last detail matters more than many apps do. The future self who returns to a task is often tired, interrupted, or short on time, and systems that assume a fresh, fully resourced person are poorly designed systems. Good habit architecture respects the fact that attention fluctuates, that energy is uneven, and that retrieval is expensive. The question I ask clients is less “How can you be more disciplined?” than “How can the next step be made easier to see, easier to begin, and harder to lose?” The shift sounds modest, yet it changes the emotional texture of a day because it removes dozens of tiny acts of reconstruction.

There is, finally, a moral undertow to this subject that deserves naming. Adults who tire quickly from fragmented task loads often conclude that they are lazy, fragile, or somehow unsuited to serious work, especially when their output comes in bursts rather than in a smooth visible line. After years of coaching, I think the harsher explanation is usually the less accurate one. Many are paying a cognitive tax that their workplace neither measures nor respects, and they are trying to cover it with willpower, which is an expensive currency for routine operations. A better arrangement of attention, cues, and task design will not solve every problem, but it can return a surprising amount of strength to people who assumed they had lost it.

If this way of working sounds familiar, moinaki has more on building environments that ask less of memory and more of design.