When stress becomes sustained over long periods, our brain tends towards more habitual behaviours that demand less energy. Our ability to control our impulses, remember information and make decisions becomes impaired. Over time, our immune system is affected. In the short term, adrenaline gives our immune function a boost to help fight bacterial and viral infections. But in the longer term, over-production of adrenaline and abnormal patterns of cortisol are linked with shorter life expectancy
