It’s often the youngest workers who seem to have the most trouble finding their niche in the workplace, but a new study from human resource firm Robert Half finds that true professional discontent kicks in after age 35 for most employees.

According to the more than 2,000 UK employees surveyed, one in six British workers over the age of 35 said they are unhappy at work - double the number of those under 35 who felt the same.

The report, which examines the influences of workplace happiness, found that older workers tend to experience more stress on the job than their younger colleagues.

Results indicate that 34 per cent of professionals over 35 found their jobs to be stressful, compared to 25 per cent of employees ages 18-35.

A number of factors may contribute to higher levels of stress in the workplace, but one common denominator for older professionals could be the added responsibility of trying to balance a family and professional life.

Of those surveyed, 12 per cent of workers age 35-54 and 17 per cent of those over age 55 said they struggle to juggle the demands of work with other aspects of their life, compared to just one in 10 millennials.

Additionally, 15 per cent of employees age 18-35 said they feel undervalued in the workplace, while 25 per cent of those age 35-54 and 28 per cent of those age 55 and up feel underappreciated by their employer.

Employees that are aged over 35 have valuable experience that the whole organisation can learn and benefit from, explained Robert Half UK Senior Managing Director Phil Sheridan in a statement.

It’s important that their happiness is not neglected, so businesses need to take the time to invest in their staff at all levels.

Some companies are beginning to recognise the value of implementing work-life balance policies that go beyond the standard perks.

Take for instance Shashank Nigam, CEO of the aviation marketing firm SimpliFlying.

To make sure that his employees avoid workplace stress as much as possible, he and his team have implemented a mandatory vacation policy that requires all staff to take a one-week vacation every eight weeks.

Because we are a small company we have to fight hard to attract the top talent, Nigam tells CNBC Make It.

A strong culture is a good way to market ourselves to potential employees and attract the best talent.