The trial ran for three months between July and October and collected data on Thrive employees, incorporating research tests such as MRI scans, blood tests, and sleep tracking. All participants completed a set of questionnaires on a weekly basis covering workplace experience and wellbeing, while regular feedback was taken from Thrive customers to determine any impact on quality of service. Sales and product metrics were also evaluated to assess business productivity.

Four-day work week demonstrates physical and mental health benefits

According to the trial results, notable improvements were seen in employee wellbeing, particularly related to stress levels, sleep quality, and detachment from work.

Participants experienced on average:

• A 22.5% increase in psychological detachment from work, indicating a significant improvement in work-life balance
• A 21% increase in overall wellbeing, and a 20% reduction in sleep problems
• A considerable 8.6% reduction in perceived stress and a 6.2% improvement in sleep quality after the trial period
• Emotional exhaustion burnout decreased by 14.7%, while depersonalisation burnout saw a slight decrease of 2.3%
• Feelings of personal accomplishment increased by 11.4%

Anxiety symptoms saw a statistically significant 5% reduction by the end of the trial. Notable decreases were also observed in stress and depression

“The results speak for themselves”, said Dr Charlotte Rae, Research Lead, University of Sussex. “These significant improvements in areas related to physical and mental wellbeing demonstrate the transformative power of a four-day work week. Improved sleep quality and reduced stress and exhaustion are factors that could have a significant impact on our health, with the potential to enhance our lives in- and outside of work. This study provides further compelling evidence for the benefits of flexible working models.”

Impact on workplace productivity

In terms of overall performance, despite working fewer hours, task execution remained consistent. Positive results were observed regarding goal attainment, which increased 19.4% with staff also reporting a 9.3% increase in self-efficacy, reflecting a boost in their confidence and belief in their ability to achieve desired outcomes at work. Statistical analysis found a significant difference between the average level of goal attainment before and during the trial.

While major improvements were recorded from a wellbeing and productivity perspective, some impacts were observed at a business level, particularly when it came to providing consistent customer service. Thrive will consequently look to implement a four-day work week on a seasonal basis going forward.

“Our four-day work week trial revealed incredibly encouraging results and we saw a fantastic impact on the people within our business,” commented Cassie Gasson, Co-CEO, Thrive. “While we would have loved to implement it on a full-time basis, our experiences in the trial also highlighted that the success of a four-day work week will rely on widespread cultural change across the UK business landscape. As a business serving hundreds of organisations, it highlighted that five-day coverage for our customers is essential when they’re operating more traditional ways of working.

“New flexible working guidelines are a positive start, but the UK government should consider implementing policies which could help make a four-day work week a reality. This will enable more modern businesses that are ready to adopt this transition to do so.  The benefits are evident through its potential to boost business productivity, increase wellbeing, and generally make the country happier and healthier and the UK has the potential to take the lead on this by pioneering the four-day work week and reaping the rewards. Until then, it’s difficult for us to commit full time and will look at a more flexible seasonal approach to support the great benefits proven.”

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