Two people can face identical workloads and experience them entirely differently. The variable that most reliably explains the difference is how much control each has over how the work is done.
Demand and control are separate dimensions
Research on working conditions has consistently found that high demand alone predicts strain poorly, while high demand combined with low control predicts it well.
Jobs that are busy but self-directed tend to be reported as engaging, whereas jobs that are busy and tightly prescribed tend to be reported as exhausting.
The distinction matters practically, because it means reducing workload is not the only available intervention, and often not the most effective one.
Control operates on timing and method more than on volume
Few people expect to choose how much work exists. What makes the difference is influence over the order tasks are done in, when breaks occur, and how a task is approached.
These are comparatively small permissions, and they are frequently the first thing removed when an organisation tries to standardise its processes.
Standardisation may improve consistency while simultaneously removing the buffer that allowed individuals to absorb variation in demand.
Predictability functions as a form of control
Knowing what is coming allows preparation, and preparation reduces the response a demand produces even when the demand itself is unchanged.
This is why late notice of shifts, unclear priorities and last-minute changes are reported as stressful out of proportion to the additional work they create.
Information about what is going to happen is therefore a resource in itself, and withholding it imposes a cost that does not appear in any workload calculation.
The physiological picture matches the reported one
In laboratory settings, participants exposed to an unpleasant stimulus they can stop show a smaller stress response than those exposed to the same stimulus without that option.
The effect persists even when the option is not used, which indicates that availability rather than exercise of control is doing the work.
This maps onto workplaces, where knowing that a break could be taken changes the experience of a shift regardless of whether one is taken.
Restoring small controls is usually feasible
Because the effective controls are narrow, they can often be reinstated without changing the volume of work: some discretion over sequence, protected periods without interruption, advance notice of schedules.
These changes tend to be cheap, which is why organisations that examine strain seriously usually find more scope here than in reducing headcount pressure.
Where a person has no realistic influence over their conditions and the strain is affecting their health, that is a matter for occupational health or a doctor rather than personal coping strategies.