More than a third of Americans haven't saved any money for retirement. That's the dramatic finding of a new survey from Bankrate.com, which also found that among those nearing retirement -- aged 50-64 --  26% had no retirement savings, along with 14% of those 65 and older.

The big reasons people aren’t saving enough, according to the survey: lack of access to retirement savings plans at work, especially those that automatically enroll workers, and failure to make retirement saving a priority. "Inertia is a powerful thing," says Greg McBride, chief financial analyst at Bankrate.com

But it needs to be overcome, according to McBride. "'I'll just work forever’ is not a viable strategy simply because you don't control your destiny on that," McBride tells Yahoo Finance in the video above. "When we look at long-term unemployment figures, it's most concentrated among adults over 50."

Related: 7 ways to retire happy

And Social Security -- even if the fund is stabilized and there are no cut to benefits, which is a big if -- only pays so much. Current retirees who have reached the full retirement age of 66 receive a maximum  $2,642 per month; if they're 70 or older and just started collecting, the maximum monthly benefit is $3,425.

Related: More Americans are following this smart Social Security strategy

So what should those nearing retirement do?

Save more and save it now, says McBride. "It's not about ramping up the risk in your investments as much as it's ramping up the contributions that you're making. You either give it up today or you give up a whole lot more later on."

Related: Here’s what could force a Social Security overhaul — and soon

He says even those without a workplace retirement savings program can save for retirement through an IRA if they or their spouse has earned income, and that can be done through automatic deductions from a checking account.

Despite these issues, there is some good news on the retirement front.

Those saving for retirement are starting earlier. Twice as many 30- to 49-year-olds started saving in their 20s rather than their 30s, according to the Bankrate.com survey.

"If you've started before age 30 you're on the right track," says McBride. "But If you haven't started by age 40 you're in trouble."

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