Why is 9 a.m. to 5 p.m. the magic time? It's been used for so long that it's become immortalized in song.

While the traditional 40-hour workweek remains the norm, you've changed the way you work. What used to take all day--making phone calls, waiting for the mail, driving for hours to buy supplies--can now be done with much greater efficiency.

Being an entrepreneur requires you to be efficient and productive. But filling the traditional eight-hour day by churning out more work just means you'll burn out or run your health into the ground. It's almost impossible to produce high-quality work for eight hours straight.

I think you can do a better job in five hours.

And as the economy becomes more information-based, more and more companies will be able to use the five-hour workday and thrive. Here are six tips on how to make the five-hour workday work for you:

1. Remove lunch from the equation.

Stop groaning. If you're working five hours, there's no real need for an hour-long break. You'll be able to power through your work with snacks and short breaks, then you're free to enjoy lunch for however long you like.

2. Work around school schedules.

Parents, like entrepreneurs, have all kinds of demands on their time and have to be efficient to get everything done. You can make them much happier employees by aligning their workdays with the hours their children attend school. It saves them heaps of money in childcare and gives them valuable time to spend with their kids. In return, they'll give you their full attention while they're working.

3. Set deadlines.

Managing your effort by setting achievable, firm deadlines is a great productivity tool. When my e-commerce company was a one-man show, I had to be everyone from the strategist to the shipping clerk. The daily shipments were a drain on my productivity. Other tasks would interrupt if I started them first thing in the morning, and I'd end up spending most of the day getting the shipments ready. So I decided to give myself a deadline.

The UPS guy came at 4 p.m. every day, so I only allowed myself to start preparing the shipments about two hours before that. By playing my fun game of "beat the UPS guy," I opened up the earlier hours in my day for greater productivity.

4. Only employ ambitious and disciplined people.

The five-hour workday only works with ambitious and disciplined people. The best performers will come in and tackle their current task load and ask for more; these are the elite you want on your team. Then, create dream jobs for them by letting them play to their strengths.

5. Make employees your stakeholders.

Do whatever you can to make your team feel empowered, rewarded, and connected to your company's success. Be generous--reward people who are really knocking it out of the park with random bonuses for their extraordinary effort. This will become part of your company culture, and people will fill their five hours with tremendous work in return.

6. Use those extra hours to stay healthy.

Being a knowledge worker takes a lot of brainpower. You need to be mentally switched on in different ways over the course of a day. To knock out task after task, you have to give your brain and body a break. Once you've worked your five hours, use the rest of the day to exercise, rejuvenate, and sleep. In the long run, staying healthy will make you even more productive.

The five-hour workday isn't just a myth you've heard about around the water cooler. It's real, and it can work for your team. The world has changed, and it's time for your workday to catch up.