Nagoya Journal of Medical Science

Diurnal rhythm in body temperature and heart rate of 12 healthy athletes were recorded during a TransPacific voyage from Japan to the west coast of the United States. The speed of the ship was 14-16 knots which caused shortening of the actual length of a day by 32 minutes. The ratio of the lag of change in diurnal body temperature rhythm did not seem to be constant throughout the voyage. The adjustment of the rhythm to a new local time seemed to occur slowly during the first few days but fairly fast after the second week on the ship. During the voyage the rhythm was approximately 2 hours behind the typical temperature rhythm of the local time, and the rhythm could follow the new environmental routines in 3 or 4 days after arrival in USA. The results obtained suggest that the intrinsic biological rhythm formed during a longer period of time resists greatly distortion by a new environmental rhythm even with moderate speeds in trans-position.

EKGs recorded with radiotelemetry were analysed while engaged in mountaineering at 4,200-7,000 m above sea level and in experiments performed in a hypobaric chamber on members of the expedition confined. During confinement in the low pressure chamber (at simulated altitudes of 6,000-7,500 m), fiat or inverted T wave and a marked suppression of the ST segment were observed in II, III, _aV and V_2-5 leads especially on the first day. These pathological signs, however, greatly improved during the following days. The most important features in EKG during exercise in Mt. Aconcagua were 1) prolonged QT time, 2) higher voltage P wave, 3) suppression of PQ segment and 4) sinus tachycardia. 1) Low voltage P wave, 2) appearence of U wave and 3) bradycardia were characteristic changes in EKG during sleep. These results show the existence of hypertension in the pulmonary circulatory system even in subjects apparently well acclimatized to the high altitude. The mechanisms mobilized in acclimatization to long term exposure at lowered barometric pressure may be somewhat different from those of short term adaptation by repeated daily exposures to the simulated high altitude.

Using the reflection photoelectric plethysmograph, rhythmic fluctuations of the blood flow were investigated in the human skin. Frequency and amplitude of the rhythmic fluctuations were not synchronous with those in other skin areas. They increased with increase in ambient temperature as well as local heating of the skin. On the contrary they decreased with decrease in ambient temperature as well as local cooling of the skin. A rise in the local venous pressure caused an increase in frequency. The rhythm was suppressed by a cutaneous nerve block, though the suppression was not persistent. Intravenous injection of a large amount of chlorpromazine caused a marked increase in frequency. Rhythmic fluctuations of the blood flow through the fingers and toes of some patients were also investigated. The results suggest that the myogenic automaticity of the vessels may be mainly involved in the rhythmic fluctuations of the blood flow through the skin, and that it may be under the influence of sympathetic nerve activity, perhaps organized at the spinal level.