Did I say “tends to prevent worry”？That is putting it mildly.Dr.Edmund Jacobson goes much further.Dr.Jacobson has written two books on relaxation：Progressive Relaxation and You Must Relax；and as director of the University of Chicago Laboratory for Clinical Physiology，he has spent years conducting investigations in using relaxation as a method in medical practice.He declares that any nervous or emotional state “fails to exist in the presence of complete relaxation”.That is another way of saying：You cannot continue to worry if you relax.
So，to prevent fatigue and worry，the first rule is：Rest often.
Rest before you get tired.
Why is that so important？Because fatigue accumulates with astonishing rapidity.The United States Army has discovered by repeated tests that even young men—men toughened by years of Army trainingcan march better，and hold up longer，if they throw down their packs and rest ten minutes out of every hour.So the Army forces them to do just that.Your heart is just as smart as theU.S.Army.Your heart pumps enough blood through your body every day to fill a railway tank car.It exerts enough energy every twenty-four hours to shovel twenty tons of coal on to a platform three feet high.It does this incredible amount of work for fifty，seventy，or maybe ninety years.How can it stand it？Dr.Walter B.Cannon，of the Harvard Medical School，explains it.He says：“Most people have the idea that the heart is working all the time.As a matter of fact，there is a definite rest period after each contraction.When beating at a moderate rate of seventy pulses per minute，the heart is actually working only nine hours out of the twenty-four.In the aggregate its rest periods total a full fifteen hours per day.”
During World War II，Winston Churchill，in his late sixties and early seventies，was able to work sixteen hours a day，year after year，directing the war efforts of the British Empire.A phenomenal record.His secret？He worked in bed each morning until eleven o’clock，reading papers，dictating orders，making telephone calls，and holding important conferences.After lunch he went to bed once more and slept for an hour.In the evening he went to bed once more and slept for two hours before having dinner at eight.He didn’t cure fatigue.He didn’t have to cure it.He prevented it.Because he rested frequently，he was able to work on，fresh and fit，until long past midnight.
The original John D.Rockefeller made two extraordinary records.He accumulated the greatest fortune the world had ever seen up to that time and he also lived to be ninety-eight.How did he do it？The chief reason，of course，was because he had inherited a tendency to live long.Another reason was his habit of taking a half-hour nap in his office every noon.He would lie down on his office couch—and not even the President of the United States could get John D.on the phone while he was having his snooze！
In his excellent book，Why Be Tired，Daniel W.Josselyn observes：“Rest is not a matter of doing absolutely nothing.Rest is repair.”There is so much repair power in a short period of rest that even a five-minute nap will help to forestall fatigue！Connie Mack，the grand old man of baseball，told me that if he doesn’t take an afternoon nap before a game，he is all tuckered out at around the fifth inning.But if he does go to sleep，if for only five minutes，he can last throughout an entire double-header without feeling tired.
When I asked Eleanor Roosevelt how she was able to carry such an exhausting schedule during the twelve years she was in the White House，she said that before meeting a crowd or making a speech，she would often sit in a chair or davenport，close her eyes，and relax for twenty minutes.
I recently interviewed Gene Autry in his dressing-room at Madison Square Garden，where he was the star attraction at the world’s championship rodeo.I noticed an army cot in his dressing-room.“I lie down there every afternoon，”Gene Autry said，“and get an hour’s nap between performances.When I am making pictures in Hollywood，”he continued，“I often relax in a big easy chair and get two or three ten-minute naps a day.They buck me up tremendously.”
Edison attributed his enormous energy and endurance to his habit of sleeping whenever he wanted to.
I interviewed Henry Ford shortly before his eightieth birthday.I was surprised to see how fresh and fine he looked.I asked him the secret.He said：“I never stand up when I can sit down；and I never sit down when I can lie down.”
Horace Mann，“the father of modern education”，did the same thing as he grew older.When he was president of Antioch College，he used to stretch out on a couch while interviewing students.
I persuaded a motion-picture director in Hollywood to try a similar technique.He confessed that it worked miracles.I refer to Jack Chertock，who is now one of Metro-Goldwyn-Mayer’s top directors.When he came to see me a few years ago，he was then head of the short-feature department of M-G-M.Worn out and exhausted，he had tried everything：tonics，vitamins，medicine.Nothing helped much.I suggested that he take a vacation every day.How？By stretching out in his office and relaxing while holding conferences with his staff writers.
When I saw him again，two years later，he said：“A miraclehas happened.That is what my own physicians call it.I used to sit up in my chair，tense and taut，while discussing ideas for our short features.Now I stretch out on the office couch during these conferences.I feel better than I have felt in twenty years.Work two hours a day longer，yet I rarely get tired.”