When major disasters like Hurricanes Harvey and Irma strike, the first priority is to keep people safe. This process involves dramatic evacuations, searches, and rescues, with millions witnessing heart-breaking images on live and social media.

All of these stressors become imprinted in our hearts and brain and can last for days, weeks, months, or longer, mental health experts say. In addition, they note that after the initial emergency passes, the long process of rebuilding and healing begins.

And for many people, the post traumatic stress following a natural disaster can be deadly.

“When our brains perceive that we don’t have enough resources to cope with our current demands, it triggers a cascade of reactions and rampant hormones in the body designed to help us short term to run away or fight off danger. However, if we don’t mobilize these reactions in some way to turn into a positive direction, they [end] up flooding our system for too long and become toxic,” says Dr. Heidi Hanna, Ph.D., executive director of the American Institute of Stress and author of a new book, “The 7 Habits of Stress Mastery.”

She tells Newsmax Health the impacts of post-traumatic stress go well beyond psychological issues.

“If our system is already compromised from being too stressed out, the excess of negative stress hormones may trigger cardiovascular events,” she explains. “So it is crucial to deal with the symptoms of stress by turning negative emotions into positive action.”