Determination of equivalent amounts of kinetic energy, work, and heat energy in the human body

J Gravit Physiol. 2002 Jul;9(1):P185-6.

Abstract

The goal of this study is determine the mechanical equivalent of heat and the functional capacity of metabolism of walking at a slow pace (velocity = 4022m/hour, length of a step=75cm, energy utilization of a 70 kg person is 200kcal/hour). 50 healthy physicians were chosen randomly, and up and down motion of the body were determined as 6cm while stepping. Based on these, the heat equivalent is 37.5kcal/hour for horizontal motion and 52.7kcal/hour for 6cm up-and-down bobbing motions of body, and the functional capacity of metabolism is at least 45% ([37.5+52.7]/200=45%) for slow walking state, that this capacity is twofold more than earlier information. Muscle converts kinetic energy (work) to heat via friction, and heat sources of the body, and the concepts of thermogenesis and the functional capacity of metabolism should be revised.