SAN FRANCISCO — After noticing that workers were often absent in its call centers around the country, Comcast Corp. implemented a resilience training program to get employees back in the office and more productive on the job.

A study commissioned by the Philadelphia-based cable company found that the majority of time when employees didn't show up for work, stress was “a huge factor,” Dr. Tanya Benenson, Comcast's chief medical officer, said during a panel discussion Wednesday at the Integrated Benefits Institute's annual forum in San Francisco.

“People are bringing their work stress home and their home stress to work and now there's this vicious cycle … You know that's going to impact productivity,” Dr. Benenson said.

Comcast's wellness initiatives at the time — lectures, an employee assistance program, meditation, yoga, and tai chi — weren't doing enough to alleviate worker stress, so Comcast turned to a digital tool that teaches employees to be resilient in the face of stressful situations.

That is, it teaches workers to be “aware and then challenge and adapt their thinking for better and more productive behaviors,” said Boston-based Jan Bruce, CEO of meQuilibrium, the online resilience training tool adopted by Comcast.

Workplace stress contributes between $125 billion and $190 billion to health care costs annually, or 5-8% of the national spending on health care, according to a January 2015 report by researchers at Harvard Business School and Stanford Graduate School of Business.

Most U.S. employees are working to help alleviate employee stress. A Buck Consultants at Xerox May 2015 survey found that 61% of companies have held stress awareness campaigns, and 50% said they offer yoga, relaxation, and mindfulness programs.

But only 22% offer resilience-building programs, according to Buck.

meQuilibrium's Ms. Bruce said it's a simple fix: “We have to stop focusing merely on the end stage manifestations of stress, helping people to be calm, to relax, to breathe, to be aware and we have to address the root cause of their stress.”

Teaching resilience, she said, is the key.

Wendy Lynch, founder of Lynch Consulting and senior scientist at Health as Human Capital Foundation, with meQuilibrium, conducted a survey of 2,000 working adults, which found connections between a person's level of resilience and job performance, health issues, and willingness to stay with a company, Ms. Lynch said.

The study showed that people who reported a high level of resilience had a low level of stress, as well as fewer symptoms of stress, including headaches, muscle tension and trouble sleeping.

The study also showed a correlation between high levels of resilience and low rates of incidental absence, she said. The results were self-reported by survey respondents.

Comcast launched its pilot resilience program with meQuilibrium in July 2014. Ten percent of employees participated, and Dr. Benenson said participation continues to grow steadily.

Users of the meQuilibrium program take an online assessment to show their strengths and weaknesses, then complete an initial 30-day boot camp on building resilience. After about 90 days, users complete a survey to assess progress.

Following the pilot program, Comcast saw an 8% improvement in the stress of its employees and a 20% improvement in stress management, Dr. Benenson said.

Comcast also saw a “very clear decrease in absence” for the employees who used the tool, she said.

“If absences are based on stress, if we can build the armor for our employees and they can handle things, they don't need to take these leaves,” Dr. Benenson said.