There's times to sprint -- indeed -- but many times not to sprint. It's important to be self-aware of when there isn't any real pressure, and if you're running at like 60% effectiveness, it can be very worthwhile to rest, recharge, and invest in your health at the expense of some short-term mid-effectiveness production.
As the last Great Unifier of Japan in the Sengoku Era, Tokugawa Ieyasu, put it --
"Life is like unto a long journey with a heavy burden. Let thy step be slow and steady, that thou stumble not. Persuade thyself that imperfection and inconvenience are the lot of natural mortals, and there will be no room for discontent, neither for despair. When ambitious desires arise in thy heart, recall the days of extremity thou hast passed through. Forbearance is the root of all quietness and assurance forever. Look upon the wrath of thy enemy. If thou only knowest what it is to conquer, and knowest not what it is to be defeated; woe unto thee, it will fare ill with thee. Find fault with thyself rather than with others."