As we get older, we not only lose muscle but our brains can atrophy as well. In specific, your brain's cognitive ability to endure neurological damage due to aging and other factors weakens through the years. This consequently can make it more difficult to perform mental tasks.
Brain or cognitive exercises can aid in preserving your mental health and fitness in a similar way as your body benefits from physical exercise. As performing a variety of physical exercises can deliver more benefits that doing just one, so it is with performing different types of brain exercises too.