basal metabolic rate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The rate at which energy is used by an organism at complete rest, measured in humans by the heat given off per unit time, and expressed as the calories released per kilogram of body weight or per square meter of body surface per hour.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun physiology The amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the rate at which heat is produced by an individual in a resting state