How many times have you justified staying a half-hour or more beyond your work schedule based on the belief that spending more time on a task leads to a higher-quality result? You're not alone by basing your actions on that mindset more often than not.

Bear in mind, though, that a growing body of research suggests that extra time at the office isn't as well spent as you'd think.

1. Too Much Work Causes Cognitive Decline

Most of us don't need scientific research to confirm the brain-numbing effects of working too long. In fact, people have recognized the harmful effects of too much work for generations.

While writing his autobiography, Henry Ford brought the workweek for his employees down to 40 from 48 after he realized they were making too many errors.

There's also an Australian study from the University of Melbourne that found people over 40 who work 40 hours per week are at risk for physical and psychological stress that could potentially cause cognitive damage.

The researchers who made that discovery said that effect happens when those older than 40 work more than 25 hours per week. However, working up to that amount increases positive mental stimulation.

2. The Extra Work May Not Catch Your Boss's Eye

Some people push themselves to work beyond their scheduled hours because they think their bosses will see them as more diligent than their colleagues, thereby increasing their chances of getting promotions or excellent performance reviews.

A study conducted at a global strategy consulting firm debunked that theory, though. It found that superiors did not notice differences between people who worked more and those who did not.

One employee who did not give his real name discussed being able to work less and find more time for enjoyable things without being discovered by his superiors or demonstrating a detectable drop in performance.

Even so, the worker's colleagues perceived that he put in even more time at the office than they did and praised him for his potential.

3. Time Spent Versus Impact Made

Some analysts who weigh in about workers' belief that the length of time spent on a task dictates the output point out that perhaps quality should not be the top priority of today's workforce.

Instead, the overall impact of the work is a better metric to keep in mind, whether it's the impact on one's company, community or self-esteem.

The argument is that people can typically make the same impacts even if they don't spend countless hours making minute tweaks to their projects.

That doesn't mean people shouldn't ever devote extra time to the work they do, but only should if that decision will result in a substantial increase in impact.

4. Your Workplace Effort Could Cause a Premature Death

People often reason with themselves and promise they'll cut back once they complete a project, train a new employee, deliver a presentation and so on. However, they ultimately fail to follow through with those intentions.

If you can relate -- and especially if your job involves a lot of sitting -- consider that research from Columbia University Medical Center indicates the way you spend time at work could cause you to die too soon. The investigation looked at 8,000 workers over 45 to track their daily sedentary time.

The average amount was over 12 hours a day during time awake, and people who stayed inactive for over 13 hours were twice as likely to die prematurely as those who were not active for 11 1/2 hours daily.

A different study at University College London found that people who work more than 55 hours weekly have more incidences of cardiovascular problems, including strokes, than those who work less.

Not Just a Problem in the United States

Statistics show that Americans work more than people from any other nation in the industrialized world, and take fewer vacations, too.

However, a startling study from the United Kingdom found that the overwork problem doesn't only occur in the United States. It revealed that 22 percent of males in the United Kingdom employed full time worked long hours. In contrast, only 11 percent of men with full-time jobs in the rest of the European Union engage in overtime.

That same study also found many people in the United Kingdom cited difficulties establishing a healthy work-life balance. Those troubles sometimes had negative repercussions on their domestic relationships, too.

Time to Consider Making Changes

The evidence presented here shows that putting in late hours at the office may not cause desirable effects noticed by your boss or colleagues. It also indicates that working too much could hurt your health and increase your likelihood of death.

There's no better time to re-evaluate how you spend your time and try to change your ways by only working your expected amount of time each day and no more.

Your performance and health could get boosted as a result.