Many are just quitting: one in three workers have left a job because they didn't feel their employer cared about them as a person. If things get bad enough, employees will leave in pairs: 38 percent of the survey's respondents have encountered a colleague encouraging them to leave a job with them. Workers who are burned out are twice as likely to have tried to convince another colleague to leave the job with them.

"Employee care should be at the core of any action. Tackling burnout is about identifying problem areas, tracking them, intervening at the group level and constantly working to resolve the issues," the authors write. "But it's also about training HR and managers to spot the signs of burnout and create a safe environment to show employees you have the resources to help them recover."

The survey also found that while 52 percent of employees have noticed their company taking steps to improve their inclusion efforts since the #MeToo movement began, workplace misconduct still persists. Of those respondents who reported an inappropriate remark about some aspect of their identity, 47 percent say their issue was not handled satisfactorily.

The respondents are split on whether their employers' D&I efforts are genuine, and 51 percent have left a job due to what they perceive as a lack of inclusion.

Employers need to "sell" their inclusion efforts internally, according to the report. "Start by showing employees what your D&I goals are," the authors write. "To help your employees rally around inclusion as a cause, your internal marketing plan should include employee-run resource groups, outside expert speakers and tangible ways to further the conversation, such as a social media hashtag or an internal forum to share daily acts of inclusion."

Employers also need to make sure workers with mental health issues can feel safe to ask for the support needed to continue working, according to the report. Managers need to be trained on how to have conversations with such workers in a respectful, trusting and non-judgmental way.

"Subtle discrimination toward mental health issues cannot be swept under the rug, so holding would-be discriminators accountable requires an authentic culture for mental health accommodations," the authors write. "This starts with proactively offering tools and resources that support emotional well-being, and ends with policy transparency and consistency at the leadership level."

As workplaces continue to ask more of their employees, employers need to reciprocate by providing care and fostering engagement, the report concludes.

"In renewing your commitment to offering top-tier employee care, focus your efforts on burnout, inclusion, mental health and emotional well-being," the authors write. "When you do, employees are more engaged, more likely to stay at the company and more likely to recommend the company as a great place to work. In short, more care means better business results — and it starts with you."

Read more: 

• An employer's guide to battling burnout
• 3 tips to help employees overcome burnout and achieve work-life balance
• 6 classifications of workers, based on burnout risk