Amid calls by Social Security critics to raise the retirement age to 70, a new study found that more than 8.5 million workers age 58 and older (about 45 percent) were employed in physically-demanding jobs or jobs with difficult working conditions. The Center for Economic and Policy Research said such jobs include janitors, construction workers, housekeepers, carpenters, cashiers, truck drivers, and cooks. "These findings suggest that raising Social Security's normal retirement age higher than already scheduled would place a greater burden on older workers in occupations that require physically demanding work, as they may not be able to continue to work in their jobs into their mid-to-late 60s," the report concluded. "Due to the difficult demands and conditions of their jobs, many may have no other option but to leave the workforce before they hit the normal retirement age and receive reduced benefits." Sen. Bernie Sanders opposes raising the retirement age.

To read the study, click here.

To read the senator's letter to the White House budget commission, click here.

To read The New York Times article about the study, click here.