Are you 65 and planning to retire this year? You may be facing a whooping $172,500 health care bill. Here's what's behind the sky-high expense

“It’s not just a benchmark for retirement readiness but also underscores the importance of planning as early as possible,” Chandler Riggs, Vice President at Fidelity Investments, told FOX Business.

What Fidelity’s number covers — and what it doesn’t

The estimate assumes retirees enroll in Medicare Parts A and B and Medicare Part D, factoring in premiums, co-payments and out-of-pocket costs for medical care and prescription drugs.

But it doesn’t include long-term care — one of the biggest potential expenses for retirees — or dental, vision and over-the-counter medications. Medicare Advantage plans can offset some of these costs, but they require separate monthly premiums.

Riggs says the surge in costs is driven by several factors, including longer life expectancies and a health care inflation rate that has outpaced general inflation for years.

A wake-up call for unprepared retirees

Fidelity’s survey revealed that 17% of respondents have taken no action to prepare for medical expenses in retirement. One in five have never factored those costs into their retirement planning. Among Gen X respondents, that rises to about one in four.

Matthew Gregory, planning director at The Bahnsen Group, told FOX Business that many people have a “hands-off” mindset when it comes to health care costs during their working years because employer-sponsored plans automatically deduct premiums.

“They may not be thinking about the need for supplemental coverage on top of Parts A and B of Medicare, as well as the fact that Medicare does not cover most long-term care costs,” Gregory said. “Those expenses can snowball quickly and become a reality check.”

That reality check could force near-retirees to reconsider whether they’ve saved enough or if they need to push back their retirement date to keep employer-sponsored health benefits.

How to build a health care nest egg

Riggs recommends starting early and using tax-advantaged accounts to prepare.

One of the most effective tools is a health savings account (HSA), which offers a triple tax advantage: Contributions are tax-deductible, investment growth is tax-free and withdrawals for qualified medical expenses are also tax-free.

For those close to retirement, working a few more years could allow them to keep employer coverage, max out their HSA contributions and build up extra savings.

“The triple-tax advantage of HSAs makes them a versatile tool to save and pay for health expenses. The contributions are tax-deductible, and the HSA dollars can be spent tax-free when used for qualified medical expenses.” Riggs said.