A little bit of stress is helpful to enable you to step up to a challenge, to sharpen your focus and improve your ability to remember details about the situation you’re dealing with. This is useful when studying for an exam, about to take your driving test or getting ready to deliver a presentation to your boss.
But too much ongoing stress triggering the stress response leading to fight-flight or freeze then fails to switch off. Thinking becomes more muddled, emotions fray and sleep disturbed.
And it can lead to mental illness.