The last sixty years’ of research into the effects of hours of work, shiftwork, associated workload, fatigue and affects on social life and families has produced many findings, but no general detailed agreements. There are interesting debates about who and what to research, what methods to use, what to measure and how to interpret results. In the meantime workers and managers continue to work in difficult circumstances that research suggests has an impact on hormone secretion patterns, and, for example, on cardiac health, gastrointestinal health and breast cancer.
Here are a number of specific statements about hours of work, fatigue and fitness for work. Total agreement on these statements can’t be achieved but they would generally be supported. However, if their opposites (a statement of opposite meaning) seems absurd (see end of document) then the statements have increased plausibility; this in the best manner of the logicians ploy of reductio ad absurdum.
- There are various circumstances which argue against absolute statements, and there are individuals who believe that they react very differently to various workloads. The probabilities are high however, that all the points below apply to most workers, and increasingly so as they get older than 35. Individual differences, capacities and needs can and should be managed separately in a flexible manner. That’s what will identify a civilised workplace.
- More hours of work after eight hours per day will increase physical and psychological workload, increase the sense of fatigue and compromise concentration and vigilance. This becomes worse on the late hours of the afternoon shift and worse still on night work. All difficulties experienced are likely to worsen with more hours of work.
- Any work more than twelve hours per day is imposing a calculated and increasing OHS risk which becomes a delinquent imposition as it approaches sixteen hours of work. Again (as for most comments), afternoon and night hours increase these risks.
- The harder the physical or mental workload experienced the worse any deficit will become. Hazards such as work in isolation, chemical fumes, heat and noise will all be exacerbated by features of the hours of work.
- If it’s accepted that experienced effort is uneven across hours of work (e.g. effort at 3am is harder than 3pm) then 10 hours’ work at night may need to be considered equivalent, in terms of effort, to, say, 12 hrs in the day.
- The longer the hours of work and the worse they are, (where ‘worse’ means harder shifts or harder segments of the day), the longer, more frequent and more comfortable the rest breaks should be. On night shift for example, a 30-minute main meal-break is inadequate.
- Driving to and from work (also a job-related event) requires concentration and care. Therefore the hours of start, finish, type and length of shift and duration of travel must all be taken into account. For example, to travel home for (say) two hours after the ninth night of twelve hours’ work is an extremely risky consequence of a poor work design. In fact any travel longer than (say) 20 minutes must be considered an added risk.
- Working more than 2 x 12hr shifts at night increases the likelihood that workers’ fitness for work will begin deteriorating, and sharply so as the number of shifts increase.
- All levels of workload, effort, concentration, vigilance, and perceptual capacity, orientation, driving and monitoring tasks must be strictly evaluated against the hours of work. The hours between about 8pm and 2am must be regarded as adding an order of magnitude of hardship to any task, and 2am to 6am must be regarded as the hardest of all. Ignoring such risks is to ignore intrinsic hazards of these work designs.
Whilst hazard identification (accurately naming the OHS problem) and risk analysis (how bad?) is theoretically a useful way of approaching the hazards of fatigue this approach must never be regarded as a means of ‘managing’ more effort out of workers.
All exposure standards for other hazards, such as chemicals, fumes, dusts, fibres and noise must be reassessed in view of the amount of hours a worker works. These set exposure standards were originally calculated for an eight hour day.
It’s possible to start from the same information and data and come to different conclusions. However, there are other forms of knowing which are often accurate and much earlier. For example, take the hazards of asbestos or smoking. In each case it was known at least 50 years ago that there were serious health problems associated with each, yet there were many scientists who kept arguing that there wasn’t enough data for firm conclusions. Some of the tragic fall-out of this manufactured uncertainty is evident and growing in many graveyards around the world.
There are many ongoing OHS problems in workplaces across Australia right now, standard OHS systems, hazard identification and risk analyses are not generally being applied accurately or well. Rather than enter an extended debate about hours of work, fitness for work, fatigue, shiftwork, night work etc the following questions below should be addressed. Is there conclusive or even plausible data to suggest that the opposite (more or less) of each of the guide-statements above (1-9) provides better grounds for a safer and healthier workplace?
They can be recast as follows:
Is it true to say that –
- the statement cannot apply because individual differences are too great, too common, and the older you are above 35 the easier shiftwork and night work become.
- more hours of work above 8 hrs per day are perceived as easier by most workers. The more, the easier, and even easier on afternoon and night work.
- more hours of work above 12 and increasing to 16 gradually reduces the risk of OHS failure.
- typical OHS hazards are not affected by type of shift, hours of work, duration nor fatigue.
- an hour’s effort is an hour’s effort regardless if it’s 3pm or 3am.
- the longer and harder the shift the shorter and fewer rest breaks should be.
- duration of travel to and from work is completely irrelevant to fatigue and OHS.
- more shifts per week than, say, than 2 x 12 is irrelevant to fatigue and OHS, and in fact improves fitness for work. Segments of shifts (e.g. 8pm to 2am, 2am to 6am) are irrelevant to fatigue, workload and OHS.
What do you think, which are more plausible?
The most accurate method of tackling the issue of fitness for work is at the workplace itself with full, rich and genuine involvement of the workers affected. An accurate and relevant job event (task) description is a prerequisite, followed by the simple naming of any associated hazards and an assessment (‘what’s it feel like?’) of “how hazardous” (risk) are they. This will provide a weighting of job events (‘this is a heavier risk’).
Dos and Don’ts can then be evaluated more accurately.