Survey results released by CareerBuilder showed that the majority or 63 percent of workers think the 9-to-5 work concept is already outdated. In reality, most workers keep thinking about work even outside the office, and some of them continue checking emails while hanging out with their friends and families.

More than 1,000 workers participated in the survey conducted between May 14 and June 3. The respondents came from different fields, including information technology, financial services, sales and professional and business services, which traditionally follow the 9-to-5 work model.

The analysis showed 38 percent of workers who work on a 9-to-5 schedule spend an additional two hours working outside the office, while 50 percent admitted checking and responding to work emails even if they are already out of the office.

"Workers want more flexibility in their schedules, and with improvements in technology that enable employees to check in at any time, from anywhere, it makes sense to allow employees to work outside the traditional 9-to-5 schedule," said Rosemary Haefner, chief human resources officer of CareerBuilder, in a news release.

"Moving away from a 9-to-5 work week may not be possible for some companies (yet), but if done right, allowing employees more freedom and flexibility with their schedules can improve morale, boost productivity and increase retention rates."

And some can't stop thinking about work even before they go to sleep. Twenty percent think about it before they go to bed, while 42 percent shared that work is the first thing that comes to their minds as soon as they wake up.

The researchers looked at the gender breakdown as well, wherein they found out that more men tend to continue working outside the office compared to women, but women think about work more before they sleep than men.

While the majority of the workers admitted that it was their choice to continue work outside the office, continuing this habit can lead to an unhealthy work-life balance. In fact, thinking about work is directly affecting the leisure activities of 17 percent of the respondents.

A study published in the American Journal of Epidemiology in 2012 showed that working more than eight hours can lead to serious health problems such as stress, raised blood pressure and unhealthy diets. Therefore, experts recommend workers be responsible in balancing work and life, working "smart" to avoid long hours in the office or bringing work outside the office, and taking their breaks. Employers, on the other hand, must also do their part by promoting work-life balance, encouraging a culture of openness, and checking their work environments to ensure balance.