When you're tired, there's one thing far more effective than grabbing a coffee.

It’s a well-established fact that most of us aren’t getting the seven and a half hours of sleep studies have found is the optimum amount we need to function at our best.

Only two to three per cent of people can truly manage on less than six hours of shut eye a night – and a whole lot more of us think we can get away with it, but are failing.

For every hour of sleep you lose, you’re also losing two hours of productivity, not to mention the effects on your mental and physical health. Oh, and we’re left feeling bloody exhausted.

In 2010, a lack of sleep cost the Australian economy $15 billion six years ago, which has only grown with the rise of social media and 24 hour cycle.

So what's the solution?

"Get more sleep" is the obvious one, but when you get that sleep is the trick.

The ABC's The Money podcast looked at the economics of sleep and found an interesting suggestion - swap your coffee break for a power nap.

It's something Kate* can't imagine not doing.

Listen: This is why you need more sleep. Post continues after audio.

"I'm a night owl and I can't get enough sleep. I can't get to bed before 1:30am even if I really make an effort because I potter around, do a bit of this or that and suddenly something distracts me, any excuse to look on Facebook and then it's 1:30am," she said.

Now she naps during the day - in the office - to catch up on the sleep she didn't get overnight and says it's "invaluable".

"I go outside and eat my lunch for half an hour and then I look for a nice couch inside and I have my "blanky" [a pashmina] that I wrap around myself so people can't see that it's me then I go to sleep for 20 minutes to half an hour," she said.

"I don't always go fully to sleep but it's just really restful and rejuvenating to lie down comfortably and rest your eyes, not work and just blank out for a while. I really don't like it when something gets in the way."
Listen: Sleep-school is a godsend for sleep-deprived mums. Post continues after audio.

Just don't forget to set an alarm.

"I used to not do that and a couple of times I fell properly asleep and didn't actually wake up for a while!"

A sleep in the middle of the day is nothing new - the Spanish have been doing it for a while - but there is great evidence that if you keep naps short they are restorative and worthwhile.

While researching his book The Productivity Project, Chris Bailey tried breaking his day up with a siesta to relax.

"I'd take a full three hours every afternoon, where I would nap and disconnect from work or drink a glass of wine or read," he told the podcast.

While he says he wouldn't recommend drinking wine in the afternoon, the nap he is all for.

"Taking a nap in the middle of the day - even a one hour siesta - breaks up the day into chunks is the best thing you can do. We need to recharge - we don't have a choice," he says.

He argues that we need to live by the rule that sleep is sacred because it's where we exchange time for energy which only benefits our lives. And yes, he's still napping.

"A nap is as good as a coffee break for a lot of people because you recharge and you cultivate how much mental energy you have at the same time," he says.

"And even though that takes time to do, you have more energy afterwards and you'll be able to bring more of yourself to work. It's a jump that people need to make and it's one I advocate quite a bit."

Race you to the office sofa?