CoachThe energy expenditure of the body, in joules, is the total energy its cells release from organic molecules over a given time. Divided by the time, it is a metabolic power, in watts. At rest an adult spends about — some a day — to keep the heart beating, the brain working, the temperature at and the cells alive; this is the basal metabolism. Every activity adds to it.
Examples
Example 7.3 (Daily budgets)
A student sitting in class, walking to school and sleeping spends about a day; an hour of football adds some ; a day in the mountains with a pack, in all. A cyclist on a mountain stage of a race spends , and cannot eat enough during the day to cover it. The energy comes from food (Chapter 1): per gram of carbohydrate or protein, per gram of lipid.