The wealthiest U.S. citizens are routinely worried about finances. That's a constant, but it's only the particular aspect they're worried about that changes.

Last year around this time, a UBS survey found that investors with more than $1 million in net worth found that those investors felt that they were stuck on a treadmill: feeling the need to make increasing amounts of money to protect their families' lifestyle and prevent losing it all. Among the 77% who grew up middle class or below, 61% aspired to become millionaires and 65% felt it was an important milestone to reach the $1 million mark.

Despite the fact that 74% of those surveyed feel like they have “made it” -- 85% though hard work -- just 73% of those with $1 million to $2 million felt highly satisfied. That's compared to 78% of those with $2 million to $5 million and 85% of those with $5 million. As a result, only 37% of those with $1 million to 5 million say they live a fairlyy luxurious lifestyle, compared to 62% of those with $5 million or more

Why so stressed? Well, 58% of millionaires report feeling increased expectations for their standard of living over the last ten years, while 52% say they can't stop working without sacrificing their family's lifestyle.

“The majority of millionaires say they have worked hard to earn their wealth and appreciate the lifestyle it affords them and their families” said Paula Polito, client strategy officer at UBS Wealth Management Americas. “But enough never seems to be enough — even the wealthiest continue on the treadmill to achieve a better life.”

That was before the Fed raised rates at the end of last year. The U.K.-based deVere Group, which handles mass affluent, and high-net-worth clients around the globe, noted that their clients had every right to be skeptical of that move given the large number of U.S. workers out of the workforce, stagnant wage growth and lack of inflation. However, Benjamin Alderson, senior area manager of deVere USA, warned clients to diversify their portfolios a broadly as possible, refrain from panicking and, most importantly, stop timing the market.

“Too often we sit on cash waiting for optimum moments to invest it, only to find that the best of a recovery rally has been had before we are back in the market with only the stock broker having benefited from our strategy,” he says. “In fact, stock market falls as new U.S. rate cycles kick in are nothing new and neither are recovery rallies. The last three interest rate cycles all began with several months of losses on the S&P 500 and global stock markets, before strong recovery rallies followed.”

Once that particular fire was extinguished, wealthy investors jumped again when the new year began with China's economy slowing down and the markets sliding.Nigel Green, deVere chief executive and founder, noted that the U.S. presidential elections, the fall of oil prices, and the wobbling Brazilian and Greek economies would all contribute to market volatility in 2016.

He also countered that a lower oil price will not only boost household budgets, which is likely to increase disposable income and provide a boost to the travel sector, among others. He also noted that Japanese and European shares are likely to do well on the back of interest rate hikes in the U.S. presenting enormous opportunity for investors taking advantage of lower prices elsewhere.

“Whilst it is almost impossible to forecast with accuracy what the stock market will do in the immediate future, it can be pretty predictable over the longer-term,” Green says.“As such, volatility can provide important buying opportunities; and on a broader note, it is best to simply feed money in over time in a measured way in order to take advantage of the beneficial long-term trend of stock markets.”

This is especially important, as giving into panic now can yield a whole lot of regret later. According to another UBS survey of investors with $1 million in net worth or more conducted earlier this year, though 79% say the economic recovery has met or exceeded their expectations, 47% wish they had invested more during the rebound.

That doesn't mean lessons have been learned. Troublingly, 89% have maintained or increased their cash holdings since the crisis, while only 18% are willing to assume more risk for greater returns. Worse, 42% say the volatility has rekindled memories of the financial crisis, and almost a quarter of investors believe it signals the start of a longer term market decline.

"Even before recent volatility tested their resolve, investors struggled to weigh the economic recovery and its positive effects on their finances against the lingering emotional fallout from 2008 and 2009," Polito says. "The financial crisis appears to have cast a long shadow on investors."

Though wealthy investors disagree about how long the volatility that started in 2016 will last -- most (77%) expect it to be temporary, while nearly a quarter (23%) think it signifies that the U.S. is on the verge of a longer-term market decline -- all agree there's reason to panic. Roughly 85% believe the volatility is driven by so many factors it is too difficult to predict where markets are headed. Meanwhile, more than three-quarters (76%) think the myriad global concerns affecting markets make it challenging to understand the whole financial picture, 80% are worried about the outcome of the 2016 U.S. presidential election and 76% are concerned about the size of the country’s debt load.

But what is all of that fear but a new face on wealthy investors' deeper fears? Last year, 50% of those with $1 million to $5 million feared that one major setback (job loss, market crash, etc.) would have a significant impact on their lifestyle -- as did 34% of those with $5 million. Among millionaire parents working full-time, 63% felt a major setback would be devastating.

That fear is taking root in younger generations as well. Millennial millionaires (ages 18 to 34) experience are more likely than other generations to fear losing their wealth entirely (52%). They also fear not living up to their potential (59% of Millennials compared to 54% of Gen X-ers and 24% of Baby Boomers) and disappointing others close to them (59% of Millennials compared to 40% of Gen X-ers, 25% of Baby Boomers and 20% of the World War II generation). They're also more likely to feel pressure to keep up with other wealthy Millennials (48% vs. 44% of Gen X-ers vs. 22% of Baby Boomers vs. 14% of the WWII generation) and are overly conscious about how their wealth stacks up compared to peers (68% vs. 60% of Gen X-ers vs. 53% of Baby Boomers vs. 46% of the WWII generation).

“Achieving success at such a young age means that Millennials' wealth has a longer lifespan and therefore a greater chance of being lost, so they have to be more diligent and put in more effort to maintain their fortune and lifestyle,” says Sameer Aurora, head of investor insights for UBS Wealth Management Americas. “Millennials, more so than any other generation, are also very conscious of how their lives stack up against their peers’, so Millennials tend to put pressure on themselves to earn more and compete for a higher standing in the social hierarchy.”

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.