"We don't have government funds to carve out as much data for things like sex addictions, exercise and others, " says John Fitzgerald of the Center for Addiction Management.

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Katz also likes an exercise called "histories of the future, " originated by Center for Applied Research, a management consulting outfit.

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He designed an exercise regimen that made him the Jack Lalane of their Placerville, California, assisted living center.

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More study is needed to see how the mental stress test relates to traditional exercise testing, said Dr. Eric Rashba, professor of medicine at Stony Brook University Medical Center in Stony Brook, New York.

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"It's true that the majority of cardiovascular protection comes from exercise at more moderate levels, but there is compelling evidence that there's no upper limit, " said Benjamin Levine, director of the Institute for Exercise and Environmental Medicine in Dallas and professor of medicine at the University of Texas Southwestern Medical Center.

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