For countless millennia, stress was a reaction that kept a human alive when in a perilous situation, such as facing down a bear or big cat. But the stress response no longer has a place in our modern world despite it remaining, and it’s left us with something of a global problem that affects millions of people every year. Stress can be a powerful experience that causes both a physical and mental reaction, and in the long term can lead to serious health problems that even the best medicine can’t fix.