Book excerpt: 52 invigorating ideas for adding more life to your years. Scientists now believe that a human's true lifespan is between 110 and 120 years. Live Longer helps readers approach those triple digits and feel better than they ever dreamed by fighting off illness, cleaning up their lifestyles, defusing their genetic time bombs, and determining their "real age"-and then lowering it. Ideas range from the ordinary to the extreme: - Idea #4: Boost your immune system - Idea #10: Time for an oil change? - Idea #22: Walk the walk - Idea #26: The sleep solution - Idea #39: Save your skin - Idea #43: Brain gym