Adverse productivity and health effect of Working long hours
At the start of the Industrial Revolution of the 18th Century the rich enclosed (i.e stole) common land causing a mass influx to city living and the bleak new Manufactorys. The new capitalist class imposed long hours on their workers. Even enlightened employers imposed hours that are nowadays unthinkable. Over time it became known that long hours reduced productivity.
Just as tobacco companies rejected evidence smoking was linked to incidence of lung cancer, so businesses long refused to accept that shorter hours meant more productivity and better quality work.
Some still do.
In the US this resistance seems concentrated in the IT industry where 60 to 90 hour weeks are common and anyone who goes home after 8 hours risks being fired not for the quality of their work but simply for not working unpaid overtime to the extent that they damage their health.
In extreme cases overwork can kill: in Japan Karoshi, death by over work is a recognised workplace hazard, though death from over work is still a major risk in Japan
The damaging effects of working long hours
Productivity is optimised around a 5 day 40 hour working week. Productivity falls as soon as overtime starts and keeps falling. After about 2 months of 60 hour weeks the total productivity is the same as would have been achieved with eight 40 hour weeks.
Even for shorter periods the damaging effects of overtime are plain. The effect of 21 hours continuous work is the same as being legally drunk. This is why in the UK and other countries lorry drivers have rest periods enforced by machines in their cabs. Long periods of continuous work reduce your ability to think straight and increases the risk of a disastrous mistake, from the software developer who accidentally deletes the company database or misplaces a comma causing a space shuttle to blow up to the junior UK doctor in the 80 hour week portion of their training who, through exhaustion, kills a patient by prescribing the wrong medicine. Long hours damage workers, businesses and patients. This was recognised a long time ago: the original plan for the holocaust was to eliminate Jews by working them to death in labour camps. Nowadays companies reduce pressure on their pension funds by working their employees into an early grave.
And perhaps the worst of it is that those working long hours often do not realise they are impaired. Until they get a heart attack or stroke.
Why work yourself to death: external factors
There are two sets of pressures, external and internal. External pressures can come from managers or unrealistic deadlines combined with poor management.
Some employers assume workers are machines that do not get tired in working hours. In fact we know we get tired towards the end of the day. There are also issues of culture and bravado, especially in the IT industry where the “All Nighter” is regarded as a sign of bravery and dedication or the UK's doctor training where senior doctors claim the 80 hour week should be retained and “it did me no harm” (How do they know?), regardless if the increased risk a doctor working 80 hours will prescribe the wrong medicine. But then where lawyers bill their mistakes doctors bury them
Be fair. Managers want to get something out the door at the lowest possible cost and the easiest way, on the face of it, is to get you to work longer for no extra money.
Most managers do not work long enough to realise longer hours mean less productivity – most places I worked in the UK senior managers arrived at ten and left at three - or if they work long hours they conclude everyone else can do the same. Most are just unaware of the evidence of the benefits of a shorter working day and week
Another cause of overwork is poor time management, often in the face of deadlines. Sometimes one procrastinates too long and ends working over night.
Of course sometimes the need for this is just a matter of bad luck. Repeated or continuous long hours means management strategy needs to be reviewed. That includes your time and schedule management.
If you are self employed you are your own boss. Guess who is making you work too hard? Step back and reorganise. If your cash flow can stand it outsource time consuming tasks as much as possible. Avoid time wasters like email and phone conversations that go nowhere. Ideally you should be able to empty your inbox within 20 minutes eight days out of ten. If not work out ways to reduce your email inflow.
For the employer making workers work too long is a false saving. It is the worst way to boost productivity. Productivity falls immediately overtime starts and keeps falling. Like the accountant who ensured 250 men were idle for a complete shift by delaying payment for a part worth a hundred or sou pounds, till the supplier refused to send more unless they got paid, the manager insisting on long hours is damaging the company.
For others long hours and resultant sleep deprivation cause deterioration in mental ability (sleep has been known to help patients with Alzheimers Disease), and can lead to burn out. It is not clear whether the damage done is totally reversible or how long it will take to reverse the damage.