So. Tired. From reading email.
A day of hard mental labor---writing emails, taking the SAT, competing in the national crossword competition---can leave you beat. But how, exactly, is that possible? You haven't done any heavy lifting, at least not with your muscles. Ferris Jabr at Scientific American MIND takes a crack
at investigating this phenomenon, exploring the science on whether thinking really hard burns calories, or whether the exhaustion is coming from something else. He writes:
Although the average adult human brain weighs about 1.4 kilograms, only 2 percent of total body weight, it demands 20 percent of our resting metabolic rate (RMR)—the total amount of energy our bodies expend in one very lazy day of no activity.RMR varies from person to person depending on age, gender, size and health. If we assume an average resting metabolic rate of 1,300 calories, then the brain consumes 260 of those calories just ...
