Levine JA. Nonexercise activity thermogenesis (NEAT): environment and biology. American Journal of Physiology — Endocrinology and Metabolism 2004;286:E675-85. Levine JA. Nonexercise activity thermogenesis — liberating the life-force. Journal of Internal Medicine 2007;262:273-87. Levine JA, Eberhardt NL, Jensen MD. Role of nonexercise activity thermogenesis in resistance to fat gain in humans. Science 1999;283:212-4.