Experiencing unfair treatment or racial discrimination in the workplace contributes to poor health and high stress levels, a new study by the American Psychological Association (APA) revealed.

Almost half of adults in the United States reported that they have indeed gone through major forms of discrimination or unfair treatment. This includes being threatened or unfairly questioned by the police, being passed over for promotion, getting fired from their jobs, or being treated unfairly when it comes to health care.

The online survey was conducted by Harris Poll on behalf of APA in August 2015. Of the 3,361 adults involved in the survey, seven out of 10 adults reported that they have experienced discrimination. About 61 percent said they experience discrimination daily, such as being treated with less respect or courtesy, getting poorer service than others, or being harassed or threatened.

"What we found was there clearly was a link between discrimination and stress," said Jaime Diaz-Granados, the association's executive director for education. "We found that those folks who reported discrimination reported a higher level of stress as well as poor health as compared to cohorts in the same group that reported not experiencing discrimination."

Discrimination went across all groups, and focused ethnicity and race, gender differences and disabilities, said Diaz-Granados. But reports of discrimination were most widespread among black Americans.

More than 75 percent of black people who participated in the study said they experience day-to-day discrimination. About 40 percent of black men said they have experienced being unfairly searched, abused or threatened by the police.

For many of the participants, the anticipation of getting unfair treatment contributes to stress. Thirty percent black and Hispanic adults said they were hypervigilant about their appearance in order to be treated well, avoid harassment or get good service. The APA said this hypervigilance may be contributing to added stress.

In fact, almost one-fourth of the adults who described their health as fair or poor also reported they have higher stress levels than average, the APA said.

"It's clear that discrimination is widespread and impacts many people," said Diaz-Granados. "[W]hen people frequently experience unfair treatment, it can contribute to increased stress and poorer health."

APA's interim CEO Cynthia Belar said one-quarter of the adults in the survey said they do not always have access to the health care they need.

Hispanics, in particular, were more likely to report that they cannot access a non-emergency doctor when they need one. Hispanics also reported the highest stress levels among the participants.

On the other hand, the APA study found some positivity from the participants when it comes to stress management related to discrimination.

Despite the high stress levels, about 59 percent said they have dealt quite well in the face of discrimination.

Many participants also said they have a positive outlook, and the survey points to the strong impact of emotional support.