According to a recent report,

a person with a life expectancy of 90 would require $40,798 at age 65 to fund his or her recurring health care expenses, not including insurance premiums or over-the-counter medications, assuming a 2% rate of inflation and 3% rate of return.

Source: "How Retirees Spend Out-of-Pocket Money on Health Costs," Employee Benefit Research Institute Press Release, February 23, 2015, http://www.ebri.org/pdf/PR1113.HlthExpd.23Feb15.pdf