Charles Darwin went on two walks daily: one at noon and one at 4 p.m. After a midday meal, Beethoven embarked on a long, vigorous walk, carrying a pencil and sheets of music paper to record chance musical thoughts. Charles Dickens walked a dozen miles a day and found writing so mentally agitating that he once wrote, ‘If I couldn’t walk fast and far, I should just explode and perish.’ Philosopher Friedrich Nietzsche concluded, ‘It is only ideas gained from walking that have any worth.