More than seven in 10 Americans nearing retirement say they are ‘terrified’ of what health care costs may do to their retirement plans, according to the sixth annual Nationwide Retirement Institute survey conducted by Harris Poll.

People are becoming increasingly reliant on federal programs to pay for their health care. The online survey of 1,316 adults older than 50 finds that 64% plan to use Social Security and 61% use or plan to use Medicare as their main sources to pay for their health care costs in retirement. Less than half use or plan to use savings to cover health care expenses.

Most older Americans acknowledge they are unprepared for certain health care expenses, yet they’re not acting to save now. One in three of those nearing retirement say they are not doing anything today to save for health care costs in retirement.

Among actions that non-retirees are doing now to save for health care costs in retirement: 41% are building their savings, 33% are paying off credit cards and debt, 28% are investing and 27% are increasing 401(k) contributions.

Largely, Americans nearing retirement are worried about the unexpected. The top concern when planning for retirement—shared by three-fourths of non-retirees—is not having the funds to cover unplanned medical expenses. One in three say they would be unable to pay for unplanned expenses as low as $500 today; more than half say they would be unable to cover more than $1,000 in unexpected expenses today; and 12% say they would not be able to cover any unplanned expenses today.

For many Americans, fears migrate beyond the unexpected to impact every day health. More than one-in-three older adults with a household income under $150,000 say they’re attempting to deflect health care costs in retirement by taking negative steps including spending less on groceries, delaying seeking treatment for illnesses and skipping preventative screenings.

As aging Americans need to rely on others for care, family members are often the first line of defense. Half of these adults are worried they will become a burden to their family as they get older, but 62% say they would rather die than live in a nursing home.

However, despite the overwhelming concerns about care, nearly half of older adults have not discussed health care costs in retirement with anyone. Half of married adults haven't talked with their spouse about it, and eight in 10 adults with children haven't talked to their children about their plan to address health care needs in retirement, most often because they don't want to worry them.

Fifty-seven percent of those who have a financial adviser haven't talked with their financial adviser about health care costs; most commonly because they consider it a personal issue. Of those who have discussed retirement with a financial adviser, 75% say it is very important or important their adviser talks to them about health care costs, compared to closer to half (53%) last year.

Even more see their adviser as a good source of information on the topic—with eight in 10 who have discussed retirement with a financial adviser saying their adviser is well-equipped to discuss health care costs in retirement. While only 28% of older adults work with a financial adviser, the survey finds that, of those who do, 65% plan to discuss health care costs with an adviser.