In an aging U.S. in which the younger generation starts work later, maintaining the labor force means that people need to work well past the age of 65. A team led by Kenneth G. Manton of Duke University argues that the nation should dramatically increase research to boost longevity of the workforce and to lower age-associated health costs. Using economic and demographic data, the group has calculated ideal amounts for the U.S. to invest in biomedicine.

Projected U.S. population in 2034: 375 million

Number who will be 65 years or older: 75 million

Optimal level of annual biomedical investment as a percent of gross domestic product: 12.8

Expressed as an amount in today's economy: $1.6 trillion

Current U.S. investment: $360 billion

Economic value of increased life span, 1970–2000: $95 trillion

Value after removing health care expenditures: $60 trillion

Annual percent decrease in disability for those 65 and older, 1982–2004: 1.5

Expressed as a number who did not become disabled: 2.7 million

Medicare dollars saved if trend continues to 2034: $810.2 billion

SOURCES: U.S. Census Bureau; Proceedings of the National Academy of Sciences USA online, June 15