(CNN) It may sound counterintuitive, but working less could actually result in higher productivity. Seriously.

Although many of us continue the tradition of working at least eight hours per day, with an hour's break in the middle -- if we're lucky -- a recent study found that productivity is actually highest when people spend fewer hours working, according to researchers at the Organisation for Economic Co-operation and Development , which examined working hours in several countries over a period of 22 years.

In fact, one paper (PDF) suggested that output actually starts to fall if people work more than 48 hours per week. Data on munition plant workers in Britain during World War I showed that long hours led to fatigue and stress that not only reduce productivity, they make accidents, errors and sickness more likely.

A hundred years later, we're still facing the same issues. Today, working overtime has been linked (PDF) to higher rates of injury, illness, weight gain, alcohol use and smoking and, in general, an increased risk of mortality. One study found that putting in long hours could result in a 40% higher likelihood of coronary heart disease, compared with people who work standard hours.

Reducing our working hours could, therefore, make a huge difference to our health and well-being, in turn enabling us to work more efficiently. In Sweden, this theory is being put to the test -- with promising results.

Stress-free in Sweden

68 nurses are working six-hour shifts in a In the Svartedalen elderly care home in Gothenburg,68 nurses are working six-hour shifts in a 22-month trial (PDF) led by researchers at Pacta Guideline , a consultancy company for the public sector in Sweden. The nurses have been working these hours since February 2015.

The researchers are monitoring the nurses' health and productivity and comparing this against a control group working in a similar facility which is clocking in 38-hour weeks.

The city of Gothenburg decided to run the trial in 2014 to learn what reduced working hours could mean for the country's economy and job market, as well as the effects they could have on employees and, in this case, the elderly residents they were looking after.

"The nurses in the trial have better health," said Bengt Lorentzon, a researcher on the project. "They are all much calmer and more alert."

After 18 months of working these six-hour days, 77% of nurses reported good health -- compared with 49% in the control group -- and members of the trial group have taken almost three times fewer sick days.

Being in good health is especially important when it comes to care work, Lorentzon says. For these nurses, this involves feeding the elderly, taking them for walks and building caring relationships. This is more effective if the nurses are there regularly and not taking time off because of illness or stress, as they can build a rapport with their clients, which is especially helpful when caring for people with dementia.

Less stress, more productivity

In addition to less sickness, the nurses working shorter days have been getting a lot more done, according to the report, providing 80% more activities for the elderly than the control group. This includes things like comforting them, singing, dancing and playing games with them.

Photos: Surprising reasons for stress Photos: Surprising reasons for stress Multitasking – Think you're being super efficient by tackling four tasks at once? Chances are you're not -- and it's only decreasing your productivity while increasing your stress. Hide Caption 1 of 15 Photos: Surprising reasons for stress Reacting to stress – Even reacting to stress by eating junk food or skipping your workouts can actually make your stress worse. Hide Caption 2 of 15 Photos: Surprising reasons for stress Your significant other – Even if you have a blissfully happy relationship with your live-in partner or spouse, you're both bound to do things that get on each other's nerves. Hide Caption 3 of 15 Photos: Surprising reasons for stress Everyday annoyances – We're told not to sweat the small stuff, but sometimes it's the little things that have the biggest impact on our mood, like the 20 minutes you lose looking for a parking space. Hide Caption 4 of 15 Photos: Surprising reasons for stress Other people's stress – Stress can be contagious. You can also experience stress when someone you know is affected by a traumatic event, like a car crash or a chronic illness. Hide Caption 5 of 15 Photos: Surprising reasons for stress Social media – Learning about stressful situations in your friends' lives through social media can add to your worries, but frequent social media use in general can be associated with negative body image and prolonged breakup pain. Hide Caption 6 of 15 Photos: Surprising reasons for stress Distractions – When you're so busy thinking about something else that you can't enjoy what's going on around you, that kind of distraction can be a recipe for stress. Hide Caption 7 of 15 Photos: Surprising reasons for stress Tea & chocolate – You may not think as much about drinking several cups of tea at once, or chowing down on a bar of dark chocolate—both of which can contain nearly as much caffeine as a cup of coffee, which is going to make stress even worse. Hide Caption 8 of 15 Photos: Surprising reasons for stress Expectations – If things don't go the way you expect and you get upset, rather than rolling with the punches, your stress could create a pessimistic mindset. Hide Caption 9 of 15 Photos: Surprising reasons for stress Watching your favorite sport – Watching sports can trigger the body's sympathetic nervous system, releasing adrenaline and reducing blood flow to the heart. Your body can't determine between "good" or "bad" stress. Hide Caption 10 of 15 Photos: Surprising reasons for stress Digital devices – Spending too much time virtually socializing can make real-life interactions seem extra stressful. Hide Caption 11 of 15 Photos: Surprising reasons for stress Your health – Even people who are in good shape worry about their bodies, diets and fitness levels. Hide Caption 12 of 15 Photos: Surprising reasons for stress Housework – If too many of the household chores are falling on your shoulders, that's just more stress on the pile. Hide Caption 13 of 15 Photos: Surprising reasons for stress Uncertainty – Stress can be defined as any perceived or actual threat, says Yeager, so any type of doubt that's looming over you can contribute to your anxiety levels on a daily basis. Hide Caption 14 of 15 Photos: Surprising reasons for stress Your pet – No matter how much you love your furry friends, there's no question that they add extra responsibility to your already full plate. Hide Caption 15 of 15

"This is connected to the assistant nurses feeling in better health, more alert,and less stressed, and in that situation, it's possible to take the initiative to do activities," Lorentzon said.

Despite these benefits, there's still the question of whether this idea makes financial sense.

The Svartedalen nursing home hired 17 extra nurses to ensure that the facility was properly staffed throughout the week, as reduced hours led to gaps in the care schedule. So far, the trial has cost $1.1 million, but according to the study, the addition of 17 jobs to the labor market has reduced the state's unemployment costs by $530,000.

"This is a political issue," Lorentzon said. "There's a lot of tension: Some political parties are against it; some parties would like to enlarge the trial."

David Spencer, professor of economics and political economy at the University of Leeds in the UK, notes that the trial in Sweden is small in scale and focuses only on a particular sector, but he says it could be replicated in other sectors.

"Employers may baulk at the short-run costs of reducing work hours, but they could stand to gain along with their workers from the implementation of shorter work hour schemes. The degree to which experiments like this one can be replicated elsewhere will depend on the progressive outlook of employers and of state and national governments," Spencer wrote in an email.

It's a contentious issue, and companies rolling out reduced working hours are certainly in the minority -- but they do exist. Toyota centers in Gothenburg switched to a six-hour workday 14 years ago and reported higher profits and happier staff. Some companies in the UK are following suit, such as Agent Marketing in Liverpool and accounting firm Bright Horizon Cloud in Dorset.

Working in 'sprints'

Senshi Digital , a tourism agency based in Glasgow, Scotland, began experimenting with the six-hour workday in March after the company director, Chris Torres, watched an ITV documentary about reduced work hours. Inspired, he walked into the office a few days later and announced that it would try the new hours.

JUST WATCHED We can't avoid stress, but here's how to manage it Replay More Videos ... MUST WATCH We can't avoid stress, but here's how to manage it 06:42

"You should have seen the look on some of the staff's faces. They couldn't believe it," Torres said.

"They come in at 9:30 a.m. and finish at 3:30 p.m. ... They get paid the same amount as if they're doing an eight-hour day. In fact, most of them have had wage rises since we've implemented it," he said.

His staff members also have a 30-minute lunch break, but their day is far more structured than it used to be. They work in 45-minute "sprints" with five-minute breaks and announce at the start and end of the day what they've achieved in the time.

Despite the shorter hours, productivity has spiked. Torres adds that projects that used to take two or three months are now completed in one or two.

"You've got to work a little harder, stay a bit more focused," Torres said. "There's less chat when they're doing the 45-minute sprints ... so I suppose the studio doesn't have quite the buzz it used to. But at the end of the day, we all go out and have more lunches and dinners together.

Join the conversation See the latest news and share your comments with CNN Health on Facebook and Twitter.

"I take my daughter to school in the morning, which I never used to do. ... (After work), I help her out with homework, I feed my boy -- and I look at the clock, and before I know it, it's only just gone 5 o'clock."

For Torres and his team, the six-hour workday seems to have been a success, boosting cash flow and enabling the company to take on more projects -- but this is a small business with 10 employees, and Torres has heard plenty of arguments against it.

"I've heard people say it would never work for this industry or that industry. I always say, just trial it."

It might be time to have a word with your boss.