The stresses and strains of caring for someone for 50 hours or more a week leads to “accelerated cognitive decline” in middle-aged and older people, research shows. However, providing care for only five to nine hours a week has the opposite effect, boosting brain health so much that the benefits last until older age. Carers UK called the findings “extremely worrying” and said they highlight how long hours spent providing care raises the risk of social isolation and burnout. Dr Baowen Xue, an academic at University College London and the lead author of the paper, said: “Our study shows that the caring responsibilities many people take on in later life can be a double-edged sword. “On the one hand, lighter caring responsibilities can be good for you by providing mental stimulation from interacting with loved ones or others you’re helping and a sense of purpose and usefulness.…