Meanwhile, living expenses are lofty. Healthcare costs in retirement for a 65-year-old couple now stands at an estimated $245,000, according to Fidelity Benefits Consulting.

What really drives the point home for retirees is that they have a shorter investment horizon than those still in the prime of their careers. An investor at age 70 or 75 cares very much about shorter-term portfolio gains.

As a result, financial planners report having do an increasing amount of hand-holding with their senior clients.

"They worry about ISIS, rising interest rates, income disparity, European recession, dysfunctional Congress, slowdown in China, and falling commodity prices," says Austin Frye, a financial planner in Aventura, Florida. "There is, in fact, a lot for them to worry about."

Steps To Take

Financial advisers says seniors need take a deep breath, reassess where they are at, and not make any rash portfolio decisions.

Most of all, excessive worry indicates that you may not be as risk-tolerant as you thought, suggests Wells Fargo's Toolan.

If you come to that conclusion, it is perfectly reasonable to revisit your asset allocation, particularly if you have not done so in a few years.

Wells Fargo has a quiz to that effect (http://bit.ly/1rmlGWT), which can design a portfolio that will help turn down that worry dial.

Even if you are not fretting excessively, it is possible your allocation has become out-of-whack in favor of higher-risk equities after such a lengthy bull market. Shifting a percentage into fixed income will not only steady your portfolio's volatility, but will help you sleep better at night.