If you can't sleep at night, chances are it's because of cash woes.
Money is many Americans' top worry, ranking higher than health, family and work, according to BlackRock's annual Global Investor Pulse survey.
But there can be some relief, BlackRock found. Those who are saving for a retirement feel better overall than those without a retirement savings plan, the study said.
"For too many people, investing and retirement planning are all about an intangible future," BlackRock President Robert Kapito said in a statement.
"But what we found is that there are immediate benefits for those who start early," he added. "Much as physical exercise has both short- and long-term benefits, focusing on retirement planning helps alleviate stress and improves your overall well-being today."
Retirement reset 
Millennials worried about their finances more than any other age group, according to BlackRock. Fifty-eight percent of people ages 18 to 34 said they are too focused on their current financial situation to save for their future, according to the study.
Fifty-six percent overall said they have started to save for their golden years, but only 45 percent feel confident they'll achieve their retirement dreams.
The majority of those polled said their current cost of living was the greatest obstacle standing in the way of planning, followed by health-care costs and rising prices.
In fact, more than — 57 percent — have less than $1,000 in their savings accounts, according to a separate GOBankingRates survey.
Another report by the Stanford Center on Longevity found that nearly one-third of baby boomers had no money saved in retirement plans in 2014, when they were on average 58 years old.
Among boomers with positive balances, the median savings was around $200,000.
