Does anyone get used to shift work?

What long service may be hiding about shift work, fatigue and accumulated strain

There's someone on most sites who has been doing this for twenty years.

He knows the roster. He sleeps on the plane. He has a system for the first night back and another for the final day of the swing. When someone new struggles, he tells them it gets easier, and he says it kindly because he believes it.

Much of the way experienced shift workers are rostered and spoken about assumes he's right.

New starters are expected to struggle while their bodies adjust. The people who have lasted are assumed to have worked it out. Experience becomes evidence of resilience, and the ability to keep arriving for work is treated as proof that the roster no longer carries the same cost.

The evidence behind that assumption is thinner than its confidence suggests.

What happens across a swing

A study of 70 oil and gas workers followed people through a single rotation in the Russian Arctic, measuring stress hormones, reaction speed, cardiac function and self-reported wellbeing.¹

A pattern emerged across the swing.

Stress was higher when workers first arrived, settled during the middle of the rotation and rose again towards the end. The researchers interpreted that final rise as a possible sign of accumulated fatigue and reduced physiological reserves, even though the work itself hadn't necessarily changed.

If that pattern holds more widely, the last days of a swing may not be biologically equivalent to the first. Yet workloads, expectations and incident reviews often treat every day of a roster as though the same person arrives with the same capacity.

The study also found that what workers said about their own energy and mood tracked poorly against the physical measures. People could feel that they had settled into the swing while their bodies were telling a more complicated story.

This doesn't make self-report meaningless. It means familiarity with a state may change how that state is perceived. A person can become accustomed to functioning while tired. That's not necessarily the same as no longer being tired.

Some effects may recover when rest is available

Research involving 140 Croatian nurses offers a more encouraging part of the picture.²

The nurses wore sleep trackers and provided blood samples at the end of a night shift and again after two days away from work. Immediately after night shift, rotating-shift nurses had substantially higher morning cortisol than colleagues working fixed days. After two nights of rest, the two groups were indistinguishable.

The study suggests that at least some acute effects of night work can settle when meaningful recovery time is actually there.

It also raises an obvious question: how much does the roster allow recovery to occur before the next demand arrives?

The nurses' own reports again told a different story from the measurements. Almost every nurse, including those with the poorest recorded sleep, described their own sleep as good or very good. The authors read this as adaptation, and possibly as reluctance to admit difficulty in a profession where coping is part of the job.

What people report is shaped by what they've learned to regard as normal, and by what feels safe to admit.

Experience may not offer the protection we assume

The more confronting finding is that greater experience didn't consistently correspond with better adaptation.

In the Arctic study, indicators of maladjustment were greater among workers with more years in the industry, not fewer.¹ Among the Croatian nurses, morning cortisol after a night shift was higher in those with more years of service.² Broader research on night-shift physiology has also suggested that prolonged exposure to night rosters doesn't necessarily lead to full adjustment to an altered sleep-wake cycle, but rather may tend to produce progressively impaired adaptation.³

These findings don't prove that years of shift work progressively damage every worker. Age and length of service are difficult to separate, the studies use different measures and the evidence remains limited.

But they do challenge the confidence with which experience is treated as protection.

A worker who has remained on night shift for fifteen years may have become more skilled at managing the logistics. They may know when to sleep, what to eat, how to prepare and how to present as functional.

That's genuine adaptation at the level of behaviour.

It doesn't automatically tell us what has happened at the level of physiology. The body can become practised at meeting a demand without the demand becoming free.

The cost may accumulate quietly

There's a broader framework that makes the pattern easier to take seriously.

Allostatic load describes the cumulative physiological burden created when the body repeatedly adapts to stress and disruption. Rather than looking at one hormone or one stressful event, it considers changes across multiple systems, including cardiovascular, metabolic and immune function.

Across hundreds of studies, higher allostatic load has been consistently associated with poorer physical and mental health.⁴ Long-term population research has also linked higher allostatic-load scores with greater mortality risk, particularly from cardiovascular and digestive disease.⁵

This doesn't prove that shift work caused those outcomes. It does provide a biologically plausible framework for understanding how repeated disruption may carry a cost that's paid gradually rather than through one obvious event.

The stress response also doesn't always remain visibly elevated.

Research on chronic stress and cortisol shows that output may rise when a stressor begins and change as exposure continues. Over time, the daily rhythm can become flatter or cortisol output may fall rather than remain consistently high.⁶

That's important because a single "normal" reading doesn't necessarily mean a person has been unaffected. The pattern of regulation may have changed.

A long-term worker may look calmer than a new starter because the experience is no longer unfamiliar. They may also have become less sensitive to how depleted they feel, better at working around it or less willing to name it.

Those possibilities aren't interchangeable, even if they look similar from the outside.

What workers and families describe

The physiology has a human version, and Australian fly-in fly-out workers and their partners have described it directly.⁷

Workers spoke about moving between two worlds that required different versions of themselves. On site, some became more guarded and task-focused. At home, they were expected to become emotionally available and re-enter family life, sometimes only to begin preparing to leave again.

Partners described carrying the household alone and then renegotiating responsibilities when the worker returned. The transition carried a cost in both directions.

In that study, 62% of workers said they liked the arrangement, while 64% of partners said they didn't.⁷

Both experiences can be true.

A worker may value the income, blocks of time off, familiarity and identity attached to the role while the arrangement places strain on sleep, relationships or recovery. Liking a roster doesn't make someone immune to its effects.

The same research found that formal support was often available but rarely used. Workers described a culture in which asking for help could be interpreted as not being able to handle the job, and some worried that using support services would be recorded or held against them.⁷

This changes how organisations should interpret wellbeing data.

A low rate of help-seeking doesn't necessarily indicate a low level of need. A survey showing that experienced workers are coping may reflect genuine wellbeing, but it may also reflect adaptation, guarded disclosure or a workforce that has learned which answers are safest.

Self-report remains valuable. It shouldn't be the only window through which capacity is understood.

Individual coping can't be the whole response

There's a risk in taking this evidence and responding with another sleep-hygiene course.

Workers can benefit from understanding sleep, circadian rhythms, nutrition, recovery and the signs that their capacity is changing. Personal knowledge is valuable.

But where the design of work is contributing to the strain, education alone doesn't alter the exposure.

The conditions surrounding people can't be treated as background. In a review of 22 controlled studies involving more than 6,300 healthcare workers, organisational interventions that changed jobs and tasks carried the strongest evidence for improving mental health and wellbeing. Changes to scheduling and the physical work environment also showed benefit.⁸

That finding doesn't argue against developing individual capability. It shows where that development belongs: alongside responsible work design, credible leadership and systems that give people a genuine opportunity to recover.

The nursing study illustrates the same principle from another direction. Physiological differences were no longer apparent after two days away from night duty.² Recovery was influenced by time and scheduling, not simply by whether someone possessed the right attitude towards fatigue.

It is worth being honest about how little sector-specific evidence exists to guide this. One review of organisational mental-health interventions in construction found only four eligible studies involving 260 workers, with no robust effects established.⁹ Comparable research in mining, resources and remote contracting remains sparse.

That absence shouldn't be mistaken for evidence that nothing can be done.

It means organisations can't rely only on generic claims or assumptions. They need to examine their own roster patterns, incident data, fatigue reports, turnover, conflict, health information and use of support services.

The workplace itself is already producing evidence. The question is whether anybody is looking at it as a pattern.

Context and responsibility belong together

None of this removes a worker's responsibility for the decisions they make.

A person who is fatigued late in a swing still has to decide whether they're safe to continue. Understanding why judgement may be affected doesn't make a hazard disappear or transfer the consequence elsewhere.

It does, however, change what an organisation should learn when similar events repeatedly occur at the same point in a roster.

If errors, conflict or incidents cluster in the final days of a swing, it's not enough to address each person as an isolated performance problem. The pattern may be saying something about the conditions in which those decisions are being made.

Understanding the human being beneath the behaviour doesn't remove accountability. It allows accountability to include the full situation.

The worker remains responsible for raising the concern they can see. The supervisor is responsible for how that concern is received. The organisation is responsible for examining whether its systems are repeatedly placing people in conditions where sound judgement becomes harder to sustain.

What this changes

Length of service shouldn't be used as a shortcut for resilience.

It demonstrates experience, skill and continued participation. It may also represent years of exposure.

Organisations should examine where incidents, errors, interpersonal conflict and wellbeing concerns occur across a roster. If problems repeatedly appear during the back half of a swing, that's not anecdotal. It's an operational pattern that can be tested against information most organisations already collect.

Self-report should remain part of that picture, but not the whole picture. In workplaces where admitting fatigue is associated with weakness or employability, a survey may reveal what people believe is safe to say rather than everything they're experiencing.

And the long-serving worker shouldn't be asked only whether he's coping.

He may be exceptionally good at coping. He may have built routines, discipline and practical knowledge that allow him to function where others struggle.

The more important question is what that coping has required, and whether the organisation has mistaken his ability to carry the cost for evidence that there's no cost at all.

The research isn't yet strong enough to conclude that every worker accumulates harm rather than adapting.

It's strong enough to question the opposite assumption.

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Why this matters to our work: The Human Impact Project examines the human being beneath the behaviour while keeping organisational conditions and leadership accountability in view. Where the conditions are contributing to harm, developing the individual can't be the only response.