As the world becomes hotter, businesses may need to switch up their staff’s working pattern to cope with “uncomfortable” heat levels, according to researchers from the University of Oxford.

And it’s bad news for night owls: The experts recommended that U.K. workers will need to start their shift at 6 a.m., in order to finish by 2 p.m. and beat the afternoon heat. For those with an hour-long commute, this could mean starting the day as early as 4 a.m. to get ready and go in the warmer months.

The new study, published in the journal Nature Sustainability, claims that Britain is one of many European countries that will have to adapt the most to cope with sweltering temperatures. However, unlike its Mediterranean neighbors, it doesn’t already have working cultural norms influenced by the hot weather, such as siestas.

The new “summer hours”

Many businesses have already embraced summer hours: L’Oréal, Asos and Nike are among the growing number of companies that are allowing staff to leave work between midday and 3.30 p.m. on Fridays during the summer months.

However, instead of a means to engage workers by allowing them to clock off early, the University of Oxford study’s work schedule suggestion is more seriously aimed at avoiding a scenario where staff are annually overheating.

The experts warned that as heat builds up and becomes more unbearable as the day goes on, a 2 p.m. finish would be better than a 5 p.m. end time.

That’s why in Spain—where temperatures have approached 45°C (113F) during heatwaves across Southern Europe—businesses are leading the way and mandating workers finish (and start) their gig earlier. 

“In southern Spain, for example across Andalucia, these working patterns in summer are not new,” the study author Jesus Lizana told MailOnline. 

“It is quite common for outdoor workers in July and August (e.g. builders, agricultural workers) to shift to an early starting hour—like from 6 a.m. to 2 p.m.—to avoid working during the hottest hours of the day,” he added. “Even shops are closed during the hottest hours in summer, closing from 2 p.m. to 6 p.m. and opening again from 6 p.m. to 9 p.m.”

The scientists think changes to working hours would be especially beneficial for people for those working outdoors or in buildings not designed to withstand extreme temperatures. 

But even in workspaces equipped with the cool breeze of air conditioning units, the researchers warn of a “vicious cycle” where people burn more fossil fuels to provide energy for air con which then heats the climate still further, requiring more energy. So even office workers would do well to clock out earlier.

Copy Japan’s “Cool Biz” policy 

Along with Switzerland and Norway, the U.K. will see about a 30% increase in days with uncomfortably hot temperatures—not accounting for extreme weather events, such as heatwaves, which are becoming increasingly prevalent.

“Even a small increase in the temperatures are actually showing a high relative change which can be very impactful and make these countries more vulnerable to needing more cooling,” said Nicole Miranda. who led the study. “These increases in relative change are going to mean that we need deployment of cooling adaptation measures at a fast speed and at a large scale.”

But she warned economies against not preparing for the rising heat and later taking the easier option of installing air conditioning, which would exacerbate the problem.

So proposed solutions from the researchers include retrofitting buildings to include ventilation measures that could also be closed off to keep in heat during winter and planting more trees next to buildings to create shade. 

Meanwhile, employers could copy Japan and encourage staff to ditch their suits and dress more casually in the summer months to keep cool. 

Its government launched its policy “Cool Biz” almost two decades ago to reduce energy usage and fight global warming.

As well as asking workers to don short sleeve shirts, the government’s recommendations include keeping office thermostats to 28°C or above, getting staff to come into work earlier, allowing workers to take longer holidays in the summer, and banning overtime.