Ernest Hemingway experienced much in his brief life, before committing suicide in Idaho at age 61.  He had been an ambulance driver in WWI, was seriously injured saving an Italian soldier, was in Paris during its liberation in WWII, experienced love and loss in marriages, near marriages, and divorces, was an avid outdoorsman, fought depression, won the Pulitzer Prize, won the Nobel Prize in Literature, and ultimately took his own life at age 61.  He knew what it was like for an active, bright man to grow old.  

In The Old Man and the Sea, Hemingway tells the story of an old fisherman who after not catching a fish for 2-1/2 months, finally hooks the greatest fish of his life, and though the old man does not have the strength of his youth, he has experience, wisdom, and judgment.  Even then, nothing is easy.  Here are several quotations from Hemingway’s The Old Man and the Sea about growing old and being tough:

• “You must keep your head clear and know how to suffer like a man.”  
• “Man is not made for defeat.  A man can be destroyed, but not defeated.”
• “It is silly not to hope, and I believe it is a sin.”
• “You’re tired old man…you’re tired inside.”
• “The setting of the sun is a difficult time for all fish.”  (No doubt Hemingway meant this figuratively as well for man; that is, the setting of the sun on one’s life if a difficult time for a man.) 
• “It will be harder to eat than the whole dorado, but then nothing is easy.”
• “You’d better be fearless and confident yourself, old man.”
• “It is too late to try for strength now through nourishment.”
• “My pain does not matter, but his pain could drive him mad.”