I recently read an article in the Harvard Business Review about why working long hours is bad for business. This article resonated with me for several reasons, but mainly because over the past 2-3 years, I have been concerned with, and viewed first hand, the growing cult of working long hours.

Unfortunately, there are an increasing number of people who equate productivity and working hard with spending long hours at work. Consulting and Legal are arguably the worst culprits, but finance, tech, and various other sectors can be just as bad. Many in the tech startup world in particular seem to consider it a badge of honor to work excessive hours and sleep as little as possible.

In a lot of cases, companies have been making genuine attempts to improve work-life balance with various initiatives. These range from sending corporate communications to shutting down the office for a period each year to force people to take leave. Yet despite this, unused vacation leave reached a 40-year high in 2014.

Anyway, in an effort to fight this rising tide, I thought I would put together 4 good reasons why working long hours is detrimental and a waste of time.

1. Longer Hours Means Reduced Output

When I say reduced output, I don’t mean that each extra hour worked is less productive then the previous one (although that is also true). I mean your actual total output falls – you work longer and produce less. And the longer you work long hours, the less productive you become.

There is an exception here of course. Working longer hours for a short period (e.g. a couple of weeks to meet a deadline) can boost productivity – but this boost quickly erodes and then reverses. A good illustration of this was provided by a report from the Business Roundtable Report from 1980. The report detailed how the initial gains from extra hours were quickly eaten up by increasingly poor productivity. From the Executive Summary:

“Where a work schedule of 60 or more hours per week is continued longer than about two months, the cumulative effect of decreased productivity will cause a delay in the completion date beyond that which could have been realized with the same crew size on a 40-hour week.”

For physical workers this is one thing (the report was based on construction projects), but what about office workers? Unfortunately the story only gets worse. Shifting concrete mix or laying bricks when you are tired is one thing, but problem solving, complex reasoning and the intricacies of office politics require a higher level of focus.

Think about managing a software development project and having a team that is mentally exhausted after working long hours for months. It is not hard to imagine a scenario where the productivity of the team actually becomes negative as important files are mistakenly deleted or code is committed with catastrophic errors that then require significant time and effort to fix.

There are many reasons for this drop in productivity including mental exhaustion, depression and declining health. However the biggest driver of lost productivity is sleep deprivation.

2. Sleep Deprivation Is the Silent Killer

In addition to being a serious productivity killer, the biggest issue with sleep deprivation is that, as Dr. Charles A. Czeisler [1] explains in this interview with Havard Business Review, people consistently underestimate its impact. He goes on to explain that a person averaging four hours of sleep a night for four or five days has the same level of cognitive impairment as someone who has been awake for 24 hours – equivalent to legal drunkenness. Within 10 days, the level of impairment is the same as someone who has gone 48 hours without sleep.

The problem is, in many cases, very few people are taking this productivity loss as seriously as they should be. Consider how your boss would react if you decided to start dropping Jaeger bombs in the morning before coming to work. They are likely to be pretty unhappy, and not just because of your juvenile choice of drink. In fact, you would probably be lucky to keep your job. Yet, work long hours for an extended period, which has a similar impact on your productivity (and is a lot less fun), and you are more likely to be promoted than get a reprimand.

Again, there is a caveat here. An estimated 1-3% of people can function at a normal level on 5-6 hours sleep a night. But before you start reassuring yourself you are that person – research also shows that of 100 people who think they can function with 5-6 hours sleep, only 5 actually can. The rest have no idea they are even impaired. Which takes us to reason number 3.

3. People Do Not Realize When They Are Not Productive

A simple mistake that many people make is confusing being busy with being productive. Anyone who has spent any decent amount of time working in an office will know at least one person who seems to be perpetually busy, but never seems to get anything done[2].

The fact is that ‘busy’ and ‘productive’ are often very different things. Frantically sending emails, multitasking, scheduling pointless meetings or just doing a bunch of work that is completely unnecessary are not productive activities, but they are often the hallmarks of busy people.

But it is not just the frantically busy people who are not being productive. There is a limited amount of time that everyone is productive during a day. Consider the following scenario, which I am sure many people will recognize.

You are working late at night on a problem. You are spending hours trying to fix a seemingly intractable problem (for example, searching for the source of a bug, or trying to identify why the numbers do not add up). Eventually you give up, resolving to get in early the next day and fix it. Then something amazing happens. You get in the next morning, and within 10 minutes you have fixed the problem. In fact, you are amazed you spent so long worrying about something that was so simple to fix.

When you were trying to solve the problem the night before, did you feel impaired or less productive? Tired, frustrated, sure, but did you believe you were any less capable of solving the problem?

Here is where the downward cycle can start. People who consistently work 60-80 hours a week are (with some exceptions) mentally exhausted, but are not aware this is the case. All they see is that they have a significant amount of work that needs to get done and not enough hours to finish it. What is the first solution that comes to a weary mind in that scenario? Put in a couple of late ones and get over the hump. Maybe spend Saturday working and try get ahead a little bit.

Unfortunately, this is unlikely to work, and as they continue to increase their sleep deficit, they are increasingly likely to make mistakes and/or fall further behind.

4. We Have Already Learnt This Lesson

“We learn from history that we do not learn from history.” ― Georg Wilhelm Friedrich Hegel

The tragedy of this move towards longer hours is that we have been down this path before. The conclusion that shorter hours actually boost absolute productivity is not new, or even controversial. Ernst Abbe as early as 1900 moved his workers from a 9 hour to an 8 hour work day and noted that overall output increased. Henry Ford is another famous example. In 1926, he moved his workers from a 6-day to a 5-day workweek and again saw output increase.

These are not one-off cases. Although this push initially came from the union movement, business after business found that the overall output per worker actually increased with shorter hours.

What Can You Do?

It is easy to blame a highly competitive labor market and/or evil corporations for this trend towards ever-increasing hours. The fact is we all have some power to change the culture of our workplaces through our own actions.

As an employee, you are somewhat limited by your surroundings, particularly if you work somewhere that judges your performance on hours rather than productivity. However, assuming you do not work in a place that thinks work life balance is a list of priorities in descending order[3], there is still a lot you can do to improve your situation:

Get your rest. If you want to get back to a 40-hour week, you need to be well rested and switched on when you arrive at the office. Be prepared to actually work. Working does not include reading blogs, regularly checking Facebook/Twitter, getting into pointless arguments, or wondering the hallways. If you turn up to work and are focused on work, you will be amazed how much you can get done in 8 hours[4]. Be organized. Making the most of your 8 hours means being organized. Make lists, prioritize, plan well ahead and finish tasks early to get them off your plate. Whatever method(s) works for you, ensure when you turn up to work, you already know exactly what you need to do. Know when to leave. It is hard to understate the importance of this. Spending hours and hours late at night trying to solve a problem is possibly the single biggest time suck in the modern workplace. If it is not due that night, leave it for the morning. Go home, relax and have dinner. You will be doing everyone a favor.

Employers and managers obviously also have a key role to play. If you really want to encourage better habits in your employees (and you really, really should want to), you need to lead by example. This means:

Cut down your own hours. At the very least, work from home outside business hours. If you say one thing and do another, your staff will choose to follow actions over instructions every time. Schedule emails for business hours. If you find yourself writing emails after hours or on weekends and you do not need a response immediately, schedule the emails to go out during business hours. Push for realistic deadlines. If you repeatedly provide unrealistic deadlines for tasks and projects, staff will be forced to put in extra hours to meet them, and will often fail anyway. Set generous deadlines and aim to finish early. Tell people to go home. If you see staff repeatedly staying late and you know there is no real reason they should be staying late, send them home. Every hour they stay working late is decreasing what you will get out of them the next day. Address poor time management. Consulting, for example, is littered with examples of people being praised for pulling all-nighters to finish off a piece of work. Sure, they met the deadline. Congratulations. Now let us talk about the weeks of poor time and resource management that led to that situation in the first place.

[1] Dr. Czeisler is the incumbent of an endowed professorship donated to Harvard by Cephalon and consults for a number of companies, including Actelion, Cephalon, Coca-Cola, Hypnion, Pfizer, Respironics, Sanofi-Aventis, Takeda, and Vanda.

[2] If you work in an office and do not know anyone like this, it is probably you.

[3] If this is your case, consider an alternative job. Or alternatively, start planning for your Eat Pray Love moment to strike in a few years time.

[4] A side effect of this is you are likely to become a lot less tolerant of long pointless meetings. Be wary of anyone who doesn’t mind long pointless meetings