Both parties used basically the same regulatory machinery to try to make their plans work in the market without creating a huge "adverse selection" problem--healthier seniors opting into lower-cost plans.

Grapefruit juice-felodipine interaction in healthy seniors.

To the Editor: In "The Old and the Rested" (column, June 14), John Tierney mentions the unmentionable: he suggests that healthy seniors consider going back to work.

If you let plans design all sorts of benefit packages, that promotes choice, but it also promotes cherry-picking of the healthiest seniors.

Even for healthy seniors, safety may still be a concern.

And healthy seniors can look forward to many years of active life, thanks to the ability to repair or replace damaged joints, remove cataracts, treat heart problems, and other advances.

H.M.O.'s received fees reflecting the medical costs of the average Medicare recipient, but to maximize profits they selectively enrolled only healthier seniors, leaving sicker, more expensive people in traditional Medicare.

The appeal is obvious: Active, healthy seniors are eager to share fun times with the kids; overworked...

Though healthy seniors haven't been particularly targeted by H1N1 swine flu, seasonal influenza remains a deadly risk for many, with roughly 36,000 people in the U.S. dying from flu-related causes every year.

One problem, he said, is that developments such as his are targeting healthy, independent seniors, while the life-care term implies to some consumers that such seniors aren't well at all.