The organ in your chest you've never heard of that could be key to living longer

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If you ever muse about which parts of your body are most impacted by getting older, your heart, brain or perhaps your muscles may come to mind.

One that you probably wouldn’t think of is the thymus, a walnut-sized organ in your upper chest.

The thymus has long been known to help form the immune system in babies in the womb, but in adults, it was thought to be mostly useless, shrinking as we age.