THE BODY’S COOLING SYSTEM

Evening Star, Issue 18050, 18 August 1922, Page 8

THE BODY’S COOLING SYSTEM

WHAT TO DEINK IN SUMMER. [By'Mho Medical Correspondent o£ tho ■ London ‘ Thnes.’[ A controversy has recently been carried on about tho right kind of summer drink. No very definite conclusions seem to have been reached. This is not difficult to understand when it is realised that-the habits of all men differ. There are people who will tell you that the_ secret of hot weather health is the judicious use of whisky; there are others who regard a drop of that liquid as poison. Nor are “ innocent ” beverages such as milk, or even water, without their adherents and critics. - On a subject of this sort unanimity will, never bo reached. That is , not to say, - however, that certain general rules may not be laid down. For example, it is evident that cooling in hot weather is assisted by perspiration. Perspiration amounts to nothing more than the loss by tho body of watery fluid ; consequently it is reasonable to suppose that in hot weather a greater intake of fluid is necessary. Those who oppose this idea do so usually from personal reasons. They are not themselves given to perspiring, because they are able to keep cool, without this mechanism; consequently they do not need to drink more. That means, in other words, that they feel better on a dry diet even when the temperature is high. We may thus dismiss them from our minds as exceptions to a general rule. ■ But in dismissing them wo obtain, perhaps, an insight into the real nature of tho problem. • That is not so much a question of drinking as of maintaining our cooling system in full working order. Tho cooling system of tho body is curiously liko that employed' on every motor car. It consists fundamentally of two parts —a radiator and a fluid. The. fluid carries the heat from tho deeper parts where heat is generated to the surface parts where it is lost. It is pumped round from one place to the other. It follows that the efficiency of cooling depends upon four factors—the amount of heat being generated, tho speed of tho circulation of tho fluid, the amount of fluid, and the degree of cooling going on at tho radiator. Thus if more heat is created, other things being equal, cooling will lie less efficient: again, if the rate of circulation or the amount of fluid in circulation falls tho same effect will bo produced. Finally, a radiator exposed to cool air will bo more effective than one exposed to heat; and a damp radiator will'be better than a dry one, on account of ihe cooling influence of evaporation. If we apply Iheso considerations to the human body wo see that, in persons of somewhat weak circulation overheating will tend to occur. In order to escape this perspiration will bo profuse—i.e., the damping of tho radiator. But perspiration means that fluid will be abstracted from the body. Unless it is replaced the heat-carrying mechanism must fail. It follows that thirst must bo met by those who desire to keep coo!. Absence of thirst in hot weather probably indicates a very efficient cooling system. The presence ef thirst shows that the supply of “ water ” in the blocd’ is falling below the point of efficiency. There need, therefore, be no hesitation in drinking freely lu hot weather if one is so inclined. The nature of the drink is another matter. Alcohol, for example, tends in tho first instance to speed up the circulation; but its ultimate effect is to slow it. Consequently those who tend to suffer from overheating should avoid this stimulant during the heat of tho clay. If they indulge in it at lunch time, they are likely to spend: an uncomfortable afternoon. The proper time for the “peg” is late in tho afternoon before dinner, when (he heat is passing away. Only those with perfect cooling powers can afford to drink wines or spirits before 4 o’clock in the afternoon. Boer is different, because the amount of alcohol is very small and the amount of fluid very large. Light beer is, generally speakings a good hot weather drink. Tho same cannot bo said for aerated waters. These tend to inflate the stomach, and so set up a depressant effect on tho heart. The consequence is a slowing of tho circulation, with interference with cooling power. The same thing applies to hot drinks, A cup of hot tea on a hot afternoon mates most people perspire profusely. heat must bo got rid of it somehow. Nature at once damps tho radiator to get rid of it. Lemon squash, orange squash, plain water, light beer, or any of the non-aerated sub stitutes for it are tho wisest drinks during: summer days: They may be followed b-- stimulants in the evening, when wort i? finished and a full meal about to bo eaten.