Close your eyes and picture clouds. There, you’re meditating, which is ‘like going to the gym for your brain’, says Dr Dharma Singh Khalsa, president and medical director of the Alzheimer’s Research & Prevention Foundation in the US. MRI scans of long-term meditators show they have more of the brain folds that make us smarter. And oming for 12 minutes a day reduces your risk of depression and slows mental ageing. Sit in a comfortable chair and think of your mind as a big blue sky. When thoughts arise, imagine them passing by like clouds.