It was once commonly thought that in adolescence, brain and physical growth plateau until middle age, at which point cognitive decline begins. Scientists now know that the brain changes continually throughout the lifetime of an individual; young brains may be faster at memorizing and recalling facts, but aging brains can better see the big picture and make connections and, as a result, have more empathy for a person or situation. Successful cultures value elder adults because elders have the long view and experience to draw on. Scientists are working on the technical end, but taking control of your own healthy eating, movement and maintenance of good social connections are the best ways to inoculate yourself from the diseases of the aging brain and help you to feel robust and vibrant as you live out your golden years.
As people age, they tend to forget things more easily, like where they put the keys, or just take more time trying to remember things, like an old friend's name. Memory problems lie on a spectrum -- the most severe symptoms manifest as full-blown dementia, where entire areas of the brain have died and other parts of the brain are stimulated.
The best defense against mental health issues related to aging is to strengthen existing neural connections and forge new ones. Practice retrieving stored information through crossword puzzles or arguing with someone with a different perspective, or make new connections by learning new subjects or languages. Interacting with others helps prevent depression, and studies show people with a larger friend group have less chance of developing dementia or having it manifest with the more harmful effects.
Exercise pumps blood (and oxygen) to your brain, muscles and organs. Exercise staves off coronary artery disease and provides many positive effects, such as decreasing your chance of developing depression and dementia. If one exercise hurts your joints, back or breathing, there are many other forms of exercise that won't have the same harmful impact on your body. If in doubt, ask a doctor, physical therapist or personal trainer for advice.