The cardiac-locomotor coupling phenomenon: the contribution of Coleman.

Cardiac-locomotor coupling (entrainment of heart and exercise rates) has been the subject of a number of recent studies. This paper reviews the early work of W. M. Coleman who, in 1921, published the results of his observations on humans and a variety of other species. The animal studies were carried out at the London Zoological Gardens. Coleman's findings remain relevant to those studying entrainment phenomena. They also illustrate the importance and utility of careful observation.