Oral Calcium-loading Test-Barr and Forfar BRrrxSH exaggerated by known infant standards. In the other a response similar to that of the control infants was obtained, suggesting that calcium tolerance was now normal. Further studies of calcium tolerance in late cases of idiopathic hypercalcaemia would be of interest.We acknowledge the helpful co-operation of Professor S. G Brit. med. J., 1969, 1, 480-483 Summary: To investigate the effect of cold water on swimming four men who declared themselves good swimmers were immersed fully clothed on separate days in water at 23.70 and 4.70 C. The time that they were able to swim in the cold water was much shorter than in the warm. The two shortest swims ended after 1.5 and 7-6 minutes, before rectal temperature fell, when the men suddenly floundered after developing respiratory distress with breathing rates of 56-60/min. The other cold swims, by the two fattest men, ended less abruptly with signs of general and peripheral hypothermia.It is concluded that swimming in cold water was stopped partly by respiratory reflexes in the thin men and hypothermia in the fat, and partly by the cold water's high viscosity. The longer swimming times of the fat men are attributed largely to their greater buoyancy enabling them to keep their heads above water during the early hyperventilation.The findings explain some reports of sudden death in cold water. It is clearly highly dangerous to attempt to swim short distances to shore without a life-jacket in water near O C.

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Subjects have been immersed in water at 27 degrees C and 10 degrees C and while immersed their respiratory rates, minute volumes, and end-tidal PCO2 levels were measured. Measurements were made with the subjects at rest, exercising at approximately 0.8 liter oxygen-min-1, and very vigorously at 1.8-2.0 liters oxygen-min-1. Immersion in the cold water caused an increase in respiratory rate and a fall in end-tidal PCO2. At the moderate rate of exercise the hyperventilation persisted in relation to the oxygen demand and there was still a significant reduction in end-tidal PCO2. At the greatest rates of exercise, the end-tidal PCO2 did not differ from that obtained in similar rates of exercise in warm water. Preheating the subject in a sauna so as to increase skin temperature, with minimal change in body temperature, greatly attenuated the ventilatory and end-tidal PCO2 responses to cold water immersion. The significance of these findings is discussed.

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Subjects who had not been exercising, were immersed for 20 min in water at 13 degrees C after ingestion of alcohol. During the immersion period, total ventilation, end-tidal PCO2, rectal temperature, aural temperature, and mean skin temperature were recorded. Control experiments were carried out at the same water temperature. Blood samples (3 ml), taken immediately before the immersion period, were analyzed by gas liquid chromatography. The mean blood alcohol level was 90+/-11.2 mg-(100 ml)-1. There was no significant difference in ventilatory responses, rectal temperatures, aural temperatures, or mean skin temperatures achieved during the two cold water immersions. It would appear that for a 20-min immersion at 13 degrees C, relatively high blood alcohol levels do not affect ventilatory responses or increase body heat losses.