The legendary Henry Ford was one of the first well-known names to adopt the 40-hour work week, much to the surprise of many of his competitors.

The common belief at the time was that factories needed to run 24/7. And the average work day ran 10-16 hours, depending on the factory.

He increased factory workers’ wages to $5 per day – double what the average employee made and practically unheard of at the time.

Though controversial, these moves turned out to be excellent. Productivity immediately skyrocketed. Workers became more loyal to Ford. And they felt a greater sense of pride.

That appears to have continued to work out well for manual laborers.

But what about office workers, who use only their brains?

Can they work more? Less? About the same?

Take a look at some of the latest research below:

1. The Dangers of Overworking

Working too many hours for too many years can literally cost you your life.

The World Health Organization found that working 55 hours per week increases your risk of stroke by 35% and your risk of dying from heart disease by 35% (when compared to a 35-40 hour work week).

Productivity also falls off a cliff after 55 hours. A Stanford University study found that you literally produce nothing of value during hours 55-70.

So whatever time you put in during that range literally amounts to just thinking, talking to people, or sitting in front of your computer screen.

2. Employees Really Aren’t Even Productive All Day

If an employee puts in an 8-hour day, how much of that time do you think is truly productive?

If you’re a sensible person, you’d probably guess like 6.5 – 7.5 hours or so.

A recent study by the Bureau of Labor Statistics (quoted in an article at Inc) found that the average worker really only does 2 hours and 53 minutes of work in an 8-hour day.

Here’s what they do instead:

• Read news websites for 1 hour and 5 minutes
• Check social media for 44 minutes
• Talk about non-work-related things with co-workers for 40 minutes
• Search for new jobs for 26 minutes

There’s actually even more. But those are some of the leading things they do instead of actually working.

3. There May Be No Ideal

While you can certainly prescribe a rough range for most workers, you can’t say a certain number of hours works for everyone.

Think about your own life. Compare it to the lives of your friends and family members.

You might have more or less stressors. You have different abilities than others. They may have health problems or mental illnesses. The type of work you do differs. The company’s view on workplace habits makes a difference.

According to an article at Inverse, the biggest driver of productivity is whether you find the work meaningful or pointless.

This comes from Jon Pencavel, a Stanford University economist who authored that university’s study mentioned earlier in this post.

So, what have you learned? Will you adjust your workplace’s approach? Or, does it seem to be working for your company?

Now you have the information to make the most informed decision for your situation.