The circadian variations of the rates of excretion of urinary electrolytes and of deep body temperature.

53 apparently healthy subjects were studied for control spans of between 60 and 184 hours while they followed a regular pattern of meals, ambulance and sleep before experiments on altered time schedules. Urine was collected and deep body temperature was measured every 2 hours while they were awake, and in some rectal temperature was also recorded during sleep. Urine was analysed for sodium, potassium, chloride, phosphate and creatinine and in 26 subjects also for calcium and uric acid. The rhythms of temperature, urine flow, and rate of excretion of each urinary solute, are presented as consinors. The two rhythms most closely linked were of excretion of chloride and sodium; the choloride acrophase led the sodium acrophase by one a half hours.