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The irrelevance of age: Here, author Anthony Isola highlights 72-year-old Seattle Seahawks Coach Pete Carroll to illustrate the idea that age is just a number. The coach's passion for his job and love for life demonstrate that age is meaningless when you truly focus on what you love. Further, Isola suggests that as you age, remaining curious, hungry and spending time with children will help you maintain a zest for life.

While your fluid intelligence (ability to think logically and solve problems in new and novel situations) can potentially decrease with age, your crystallized intelligence (the accumulation of knowledge, skills and experience acquired over a lifetime) increases. This means that your second act of life is the ideal time to pass on your life wisdom to future generations, whether that be through teaching, mentoring or volunteering.

In order for you to remain truly youthful, you have to engage your sense of adventure and curiosity. If you do some digging, you’ll find they never really left you.