No one became an entrepreneur because of wanting to work less. In fact, most entrepreneurs work an insane number of hours--probably more than 60 a week. Even when entrepreneurs aren't actually working, they're at least thinking about the business.

That hard work is something that we all celebrate and boast about. But should we really be working that many hours?

It's a question that's been asked numerous times by my fellow entrepreneurs. There have been books written on the subject--see Timothy Ferriss's The 4-Hour Workweek. And there have also been studies on the number of hours entrepreneurs work--over in the U.K., it's been found that entrepreneurs work an average of 52 hours a week, which is 63 percent longer than the average worker. In short, it's a topic that apparently strikes a nerve.

Here's the thing, though. Working more than 40 hours is pointless for some people.

Sara Robinson wrote an incredible article on Salon that not only detailed the origins of the 40-hour workweek but also why working more than 40 hours isn't effective. According to Robinson, "every hour you work over 40 hours a week is making you less effective and productive over both the short and the long haul." Why? Because after putting in a full eight-hour day, you're exhausted and fatigue begins to set in. If that continues, employees get burnout--which could take weeks for them to recover from.

In short, you don't have to put in 60 or 70 hours a week. You can actually be more productive by working the standard 40 hours a week.

But that only solves one problem regarding your work schedule. The other is dealing with the time of day that you work. You can figure that out by asking the following question: Are you a lark, owl, or hummingbird?

A lark is what is commonly known as a "morning person." Larks are usually older and get up early to tackle the day first thing in the morning. Some other characteristics of larks include:

An owl is obviously a night bird and tends to be younger. Think college students. These are the people who have the following characteristics:

Hummingbirds, however, have the ability to wake up early when they have or want to or have no problem staying up late. In other words, they are burning the proverbial candle at both ends.

While it may be describing morning people and night birds simplistically, it all comes down to your biological clock and circadian rhythms.

The National Institute of General Medical Sciences describes circadian rhythms as "physical, mental, and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism's environment." This just means that some people have difficulty waking up in the morning, while others can't stay up late.

While it is possible to adapt (owls may have to wake up early for class or work, for instance), you should try to listen to what your body is telling you. If you're most productive in the morning, that's when you should be working. If you sleep in and get the bulk of work completed in the evening, then that's when you should set your hours.

So if you want to be more productive, try your best to work an eight-hour day. If not, you're going to hit a wall. And, make sure that you pay attention to your biological clock. It will clue you in on what hours of the day you should be working.