You spent Sunday on the couch, skimming your social feeds and watching HGTV. Monday at work was a different story; your job involves creative problem solving and other difficult mental activities. Does the extra brainpower you use at work burn more energy than your Sunday spent watching Fixer Upper reruns?
“The basic answer is yes,” says Ewan McNay, an associate professor of psychology and behavioral neuroscience at the University of Albany.
The brain—unlike any other part of the body—runs exclusively on the sugar glucose, and strenuous cognitive activities require more glucose than simple ones, says McNay, who has studied how the brain uses energy to perform work. During a difficult memorization task, for example, the parts of your brain involved in memory formation will start consuming more energy, but other brain areas will show no such increase.