We all grow everyday Physically and from the existing belief, we also keep stagnating at one point of time. Although new findings in the book Keep Sharp by Dr. Sanjay Gupta have shown that ailments like Dementia etc. can be prevented if people follow certain habits including exercise, socializing, yoga, healthy eating, maintaining and the good news is that even the people in older generations can keep their brain "sharp"
Similarly, if we have a "growth mindset" i.e. the mindset that focuses on constant learning and taking up newer challenges, our brain does get smarter. If you are an Educator or a trainer, you may very well emphasize this to your audience. The classic case is of London Drivers. When they get their cab license, they have to remember all the complicated routes of the city and that actually enlarges the part of the brain that is responsible for "spatial awareness". So, the longer the experience in driving, the more advanced the brain is. Although this is an example of one activity that is repeated every day, this still is a challenge. So, if you are a creative thinker and you are a constant learner and you like new challenges in your life, you are possessing a "growth mindset" that literally re-wires your brain to stay sharp and as a repercussion, you perform better at your job and you can prevent many types of stresses. And of course to keep the brain healthy, besides growth mindset we need to look at eating habits and modify them based on our body type.
To keep the brain agile and sharp, the onus is on us. We are our own heroes!