The importance of acquiring more information than is now available with respect to the physiology of exercise has not lacked emphasis in The Journal.1 Many of the facts which are learned find an immediate application in the domain of practical medicine and notably in the clinic of cardiac diseases. The enlargement of the heart, for example, may be attributable either to hypertrophy of its musculature or to an increase in its blood-volume. Both of these conditions are affected by muscular activity or exercise, but the interrelations which are involved have never been fully elucidated.
Exercise and the Heart. JAMA. 2016;316(4):464. doi:10.1001/jama.2016.10111