The four-day workweek has got a shot in the arm with the latest study finding numerous benefits to the work pattern.

The 61-company U.K. trial was organized by the nonprofit 4 Day Week Global, and the results published Tuesday said the arrangement benefits both employer and the employee.

In the trial, 2,900 workers reported lower levels of stress, anxiety, burnout, fatigue, and sleep issues, as well as improved work-life balance. Moreover, revenue remained more or less the same for the 47 companies that reported financial data.

The results are not surprising, according to Philip Gehrman, a psychologist at the University of Pennsylvania.

"As much as work can be rewarding and fulfilling, it's also stressful and takes time that we'd like to spend doing other things. So it just seems logical to me that working fewer hours would be associated with a range of improvements," Gehrman told BusinessInsider.

It should be noted the trial did have its limitations. First, there was no control group in the trial. Meaning, there was no company or companies that followed a five-day workweek to compare against the four-day workweek companies.

Second, the participating companies were allowed flexibility in deciding the schedule, and there was no common work pattern. For instance, employers could leave out Fridays, allow shorter working hours over a five-day workweek, or make the four-day week dependent on meeting performance goals.

Shorter workweeks can lead to tighter deadlines, which may not be a bad thing, according to Alex Korb, a neuroscientist at the University of California, Los Angeles.

"It helps us focus our energy and our efforts," he told Insider. "If I said you had some big project that was really difficult to do, and I didn't give you a deadline, well then it would probably take a really long time, and you might not make much progress at all."

There is research that shows that people tend to increase their effort as a deadline nears, which works in favor of employers.

Workdays can also be stressful and lead to cortisol production--a stress hormone. But prolonged stress and cortisol production can contribute to a range of physical and mental health issues.

"If suddenly you had an extra weekday — well, instead of five days of elevated cortisol, you only have four days of elevated cortisol," Korb said. "That could certainly explain why people experience reduced burnout and improved mood."

In the U.K. trial, decreases in stress, albeit at a smaller level, were observed. On a scale of one to five, average stress levels decreased from 3.07 before the trial to 2.74 post-trial.

"One of the first things that go out the window when people are stressed is their sleep," Gehrman, who directs U Penn's sleep neurobiology and psychopathology lab, said.

"When people don't get enough sleep during the week, and they sleep in on the weekends, that two days of sleeping in is not enough to eliminate the effects of five days of inadequate sleep," he explained. "But three nights of recovery for four nights of sleep loss is definitely better."

In the 4-day workweek pilot, it was also seen that 46% of employees felt less fatigued than usual.