Any forms of mental exercise is better than watching TV on the sofa. But the exercise activities that can have the most positive impact are by no means simple and easy activities: it may not be enough to play games endlessly or watch the latest documentary feature films on the history channel. Just as muscles become stronger with use, mental training can keep your mental skills and memory under tension. Don’t be too comfortable. Step out of your comfort zone and occasionally challenge your mental skills, such as traveling to a city you have never been to, which will make you constantly explore in a strange environment.