Do you think that retirement age should be tied to life expectancy?

Some of the countries in the civilized world have raised retirement age, apparently in response to the higher life expectancy of their citizens.

According to this article in the Ny Times, “In the United States, where private-sector workers born in 1960 and later already have to work to 67 to gain full Social Security benefits, government officials are looking for ways to reduce the costs of ballooning public sector pensions and are pressuring unions to agree to later retirement dates.”

I know that there are many economic reasons for such changes, but when does it get to be unreasonable to expect the senior citizens to give up their hopes for their future?

Should retirement ages be tied to increases in life expectancy, and how high should it go? If it’s simply based upon these statistics, would it reach a breaking point where people would have no opportunity to enjoy their retirement years? Being aged beyond those more energetic and healthful years, but perhaps just experiencing a longer period of declining health and less vigorous life style doesn’t seem to give aging people much to look forward to, does it? Could this be a form of ageism?