For thousands of lucky people, the work week is now only four days long – and they're still getting paid 100 percent of their regular income to do their jobs, even though they've gained an entire day of personal time.

Does it sound too good to be true? It's not necessarily an impossible dream. This idyllic work rebalancing could hypothetically become the new normal one day, if campaigns to realize a four-day work week continue to gather momentum.

Now, in what's estimated to be the largest four-day work week experiment ever conducted, 70 companies and over 3,300 employees in the UK are embracing the work-life balance shift, as part of a pilot program to trial four-day work arrangements for the next six months.

The initiative, spearheaded by nonprofit 4 Day Week Global alongside other organizations, is being run in conjunction with researchers from Cambridge University, Oxford University, and Boston College, who will investigate how the four-day week impacts workers (among other things).

"We'll be analyzing how employees respond to having an extra day off, in terms of stress and burnout, job and life satisfaction, health, sleep, energy use, travel, and many other aspects of life," says economist and sociologist Juliet Schor from Boston College, the project's lead researcher.

But it's not just workers in the UK who stand to benefit from making the move to four days. 4 Day Week Global is also conducting pilots in Australia and New Zealand, and the organization recently announced an upcoming trial in the US and Canada, with next month being the deadline for signing up, and the pilot expected to get underway in October.

Four-day work weeks or, alternatively, 35-hour weeks have been studied by researchers for years now across a number of international trials, with the largest to date being an experiment in Iceland that involved approximately 2,500 participants.

That trial found reducing hours worked by staff offered numerous benefits to employees, while not leading to drops in productivity.

"Many workers expressed that after starting to work fewer hours they felt better, more energized, and less stressed, resulting in them having more energy for other activities, such as exercise, friends, and hobbies," the researchers reported.

"This then had a positive effect on their work."

That kind of result is how it can make sense for employees to work less time while earning the same amount of money as they normally do. The thinking is that simply by having to spend less time working (and having more free time), they'll have more energy, engagement, and wellbeing, so that they can be more effective and productive in the time they do spend working.

This concept isn't just wishful thinking, either, but an in-principle commitment made by employees who take part in these programs, called the 100-80-100 model: meaning workers get 100 percent of their pay, working 80 percent of the time, in exchange for 100 percent productivity.

Another beneficiary, theoretically, is the environment, with research suggesting we may be able to reduce carbon emissions if we reduce our working hours.

"The four-day week is generally considered to be a triple dividend policy – helping employees, companies, and the climate," Schor says. "Our research efforts will be digging into all of this."

4 Day Week Global was born after the organizers' first successful four-day work week experiment at Perpetual Guardian, a trust firm in New Zealand, which enjoyed the benefits so much they elected to make the changes permanent.

"What we've seen is a massive increase in engagement and staff satisfaction about the work they do, a massive increase in staff intention to continue to work with the company, and we've seen no drop in productivity," the company's CEO Andrew Barnes explained at the time.

"We're paying for productivity."

It remains to be seen whether the new UK, Australia, and New Zealand trials (and the future US/Canada pilot) will deliver such hugely promising results, but if they do, we can expect even more support to get behind the campaign to only work four days.

Some think the transition may only be a matter of time, echoing modern society's adoption of the five-day work week in the early decades of the 20th century, which involved eliminating a sixth day of work.

"By moving first we get a lot of advantages," Paddy Lambros, head of people and talent at British tech company Sensat, which is taking part in the UK trial, told Euronews.

"We've seen an uptick in applications, we've seen an increase in sentiment, we've been able to hire more diverse people… When we tie all those things together we see a massive advantage in adopting what we think is coming inevitably anyway, earlier than everyone else."

You can find out more about the pilot and campaign at the 4 Day Week Global website.