Swimmer surrendering head for heart (3)

I believe the answer is:

hub

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'for heart' is the definition.
(hub is a kind of heart)

I don't understand how the remainder of the clue works.

(Other definitions for hub that I've seen before include "Focal point of activity" , "Central part of a car wheel" , "Nave of a wheel" , "Centre or axis" , "Wheel's centre" .)

I've seen this clue in The Sun.

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