Inconstant Heart

Because the living heart is a generator of electricity, two heart specialists were able to report in the current issue of the Journal of the American Medical Association that the heart is never constant, that there is no normal pulse, that every sensation, thought, emotion, movement changes the heart rate, that the heart is, as might be supposed, quietest during sleep. The men are Dr. Ernst P. Boas,* 38, now practicing privately in Manhattan, and Dr. Morris M. Weiss, 28, now practicing in Louisville, Ky. They made their studies on doctors, nurses, patients in Montefiore Hospital, New York, where Dr. Boas was medical director.

To trap the heart's action current they would strap two electrodes to the subject's chest, one above the heart's top, the other about six inches lower. From the electrodes ran 60-ft. wires to a "cardiotachometer," which Dr. Boas devised. Vacuum tubes in the cardiotachometer amplified the heart action current which thereupon operated a counting device and a recording pen. The long wires enabled the subject to practice most of his usual occupations. The counter recorded the total number of his heart beats over any desired period (most importantly for study, during sleep). The pen indicated on a moving strip of paper the continual variations in the beat.

The most important observation that Drs. Boas and Weiss made is that the heart rate of an individual during sleep is an index of the speed at which his heart must beat to meet his physiological needs. In sleep he is least disturbed by thoughts or outside influences. Sleeping normal heart rates ranged roughly from 40 to 55 beats a minute for males, 50 to 65 beats for females, whereas the generally accepted "normal" rate for males is 62, for females 69.

One nurse's 13-hr, record was typical of the heart's variations. When she listened to music her heart beat 98.6, its fastest. At supper it slowed to 82.5. Preparing to play cards sent the rate up; playing let it go down. Preparing for bed jumped it; turning the lights out lowered it. As she dropped into sleep the rate wobbled.

*Son of Columbia University's Anthropologist Franz Boas.