"This is, I think, one little part of what Christ meant by saying that a thing will not really live unless it first dies."

Field of wheat
Creative Commons AttributionField of wheat - Credit: Ian Britton
Trying to prolong life's thrills may be "one little part" of Christ's meaning, but it was not Christ's primary meaning. When He used this metaphor, Christ was speaking of His death and resurrection (John 12:23-26, KJV):

And Jesus answered them, saying, The hour is come, that the Son of man should be glorified. Verily, verily, I say unto you, Except a corn [i.e., kernel] of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit. He that loveth his life shall lose it; and he that hateth his life in this world shall keep it unto life eternal. If any man serve me, let him follow me; and where I am, there shall also my servant be: if any man serve me, him will my Father honour.