According to the World Health Organization, people are living longer, and human longevity will continue to increase in the coming decades. This projection yields more urgency for people to design lifestyles around activities we find mentally stimulating.

Far too often, people in the United States are retiring with plenty of “gas left in their tank,” only to find it difficult to transition into that next chapter in their life’s journey.

For some, working in retirement, particularly work that centers around a person’s passion, can be fulfilling in a variety of ways. To that point, the “out to pasture” stereotype linked to retirement, particularly in the United States is now stale and untrue.

As wealth managers for 22 years, we have watched many clients engage in activities that keep them curious or mentally "plugged in.” We have seen clients go back to school, travel to experience different cultures, embark on entrepreneurship and become part of impactful philanthropy.

They strive to learn more in areas of interest and have challenged themselves in ways that promote some healthy anxiety because they are pushing themselves outside their comfort zone. After all, as human beings, we are wired for continued growth, regardless of age.

If we remain in our comfort zone and design our life around activities that always keep us there, we aren’t necessarily growing. Experiencing personal growth and engaging in activities necessary for this growth can keep us young, engaged and vibrant.

More from Straight Talk:

Four ways retirees botch Social Security

How money can, in fact, buy happiness

Debts to watch as Fed raises rates

If we center our conversation around what we’re passionate about and what will stimulate lifelong growth, we can retire to our passions rather than just from our previous jobs or careers. We then flip the internal dialogue that has red-flagged our brains due to forthcoming change as we approach retirement. This creates ambition and excitement rather than uncertainty and hesitation. We should all be curious about the next chapter in life.

A study by University at Buffalo psychologists Todd Kashdan, Paul Rose and Frank Fincham concluded that curiosity is very good for people. Their study found that the degree to which we are curious will actively influence our personal growth.

There are many people in the United States who have amassed financial independence, allowing them to comfortably retire from their job/career. However, they’re stifled by uncertainty as to what to do next. Financially, they no longer need to work, but they have no idea what to do in their golden years. So these people continue to reluctantly work due to the uncertainty their future holds.