Among very unpleasant alternatives, raising the retirement age seems to be one of the fairest approaches across generations.
BIS Review 27/2005  7  Table 3 U.S. Workers in Physically Demanding Jobs Year  Percent in Demanding Jobs  1950  20.3  1960  13.8  1970  11.1  1980  9.1  1990  7.8  1996  7.5  Source: Eugene Steuerle, Christopher Spiro, and Richard W. Johnson (1999), Straight Talk on Social Security and Retirement Policy, The Urban Institute, August 15.