There is no good evidence to suggest crosswords prevent the brain from degradation. Actually the best exercise for the brain is well, exercise! It's also been proven to be the only thing that improves fluid thinking which begins to slow down from around the age of 30. Other lifestyle influences impact such as alcohol and drug use but the results are conclusive. Exercise is good for neurons. In a 2018 study—recently published in the journal NeuroImage—investigators reviewed thousands of articles about exercise and brain size. They found 14 studies in adults—many of the other studies were conducted in mice or children—that compared the size of a key brain region before and after exercise. The key brain region is called the hippocampus. The hippocampus is a seahorse-shaped, deeply buried region of the brain that is essential for learning and remembering new information. The hippocampus tends to decrease in size with age and it is one of the earliest parts of the brain to shrink in Alzheimer’s disease. So this is a case of "bigger is better." A larger hippocampus is a sign of brain health. The studies revealed that exercise had significant positive effects on the size of the hippocampus. Exercise appeared to prevent age-related decreases in hippocampal size, particularly in on the left, language-dominant side of the brain. The old adage 'healthy body, healthy mind' is truer than ever