The way you're using email is stressing out your colleagues, a study says. Here's how to fix it.

• Researchers investigated how non-urgent emails were received by workers when sent out of hours.
• They found that receivers can overestimate how urgently they need to respond, which causes stress.

You should always be explicit about when you expect a response to an email because failure to do so stresses out your colleagues, a recently published study suggests.

Even when an email is non-urgent, people receiving it overestimate how quickly the person sending it expects them to respond. That causes higher levels of stress, according to researchers from the London Business School and Cornell University.

They conducted eight studies with more than 4,000 participants from private and public sector organizations to investigate the impact on a person's stress levels when they receive an email, and perceptions about how quickly they need to respond. The studies, except for one, focused on non-urgent emails sent out of hours.

On average, people felt that they had 36% less time to respond to an email than the person sending actually expected. When recipients felt they needed to respond urgently, they felt more stressed.

Stress levels were worse if they received emails outside of their set work hours.

We shouldn't blame technology, but how we use it, said Laura Giurge, a postdoctoral research fellow of organizational behavior at London Business School, who was co-author of the study.

We'll often send non-urgent emails - sometimes outside of core working hours - without expecting an instant response, but fail to specify this. According to the researchers, we assume that others automatically understand what our intentions are.

The study showed that when senders stated that an email was non-urgent and not requiring an immediate response, stress decreased, and 'urgency bias' was much less among people receiving emails.

"There's a sense that other people know what's going on in our minds," Vanessa Bohns, associate professor of organizational behavior at Cornell University, another co-author, told Insider. "It's a mistake we make all the time but it means that we have to be more explicit about some of these things and that pervades all sorts of interactions."

The researchers recommend adding a quick note in your email - stating explicitly that it's non-urgent - as a way of managing perceptions. This is especially important when people are working from home, where there is more chance that people's core working hours will be different.

Bohns and Giurge said that they're often asked whether scheduling emails is another solution.

While it can seem obvious, it can cause added stress if people simply receive a flood of emails on Monday morning. It's still important to explicitly state when you expect a response and whenever an email is not urgent, said Bohns.

Giurge said the findings demonstrate a broader point about the way that we work in general.

"The research couldn't be clearer on this. Needing to disconnect from work is really important not just for our wellbeing, but also for our productivity. By not being able to unplug yourself and disconnect from work, you're not allowing yourself to really recharge. That's a bigger problem."