While air conditioners and freezers are familiar examples of heat pumps , the term `` heat pump '' is more general and applies to many HVAC devices used for space heating or space cooling .
An air conditioner is a heat pump .
An exercise physiologist 's area of study may include but is not limited to biochemistry , bioenergetics , cardiopulmonary function , hematology , biomechanics , skeletal muscle physiology , neuroendocrine function , and central and perpheral nervous system function .