Board Thread:Theories and Speculation/@comment-3568954-20141031085827/@comment-10330822-20141031093644

Because it is implied. You shouldn't need everything spelled out for you. If your lifespan is decreased it means you die sooner, which means you age sooner as well. You don't just die. Tsunade isn't going to just be walking around one day and fall over dead, she is going to get so old her Reserve Seal isn't going to be able to keep her young and she'll die a natural death.