Let’s talk a little more about aging. In each of your cells, you have forty-six strands of DNA coiled into chromosomes. At the tip of each chromosome, there’s a tiny cap called a telomere, which keeps your DNA from unraveling and fraying. Think of it as the plastic tips on the end of your shoelaces. Every time your cells divide, however, a bit of that cap is lost. And when the telomere is completely gone, your cells can die.56 Though this is an oversimplification,57 telomeres have been thought of as your life “fuse”: They can start shortening as soon as you’re born, and when they’re gone,
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