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Physiology of Clothing

physiology of clothing

A century and a half ago Count Rumford suggested that the hygienic properties of clothing merited serious scientific study. Included in the aims of the Royal Institution was the instruction of the public in the proper practice of the domestic arts, particularly those relating to “the management of heat and the saving of fuel.” Among these the application of the laws of heat to clothing and fuel economy was specially mentioned.1 That these very subjects have now become the everyday practical concern of every citizen hardly needs emphasizing; and besides these topics there are in modern war, as Sir Leonard Hill has graphically described in his recent article,2 a considerable number of situations which call for the provision of highly specialized clothing.

Wearing apparel for fighting personnel must be planned as protection against a variety of external agencies—wind, water, dust, ice, gas, and fire, as well as the climatic extremes of heat and humidity—and, withal, the garments have to be reasonably light, comfortable, strong, and serviceable. As Sir Leonard Hill says, on all these occasions the provision of the appropriate clothing requires as a basis the application of “physiological common sense.” This means particularly an appreciation of the facts of heat regulation in the human subject. But, while it is largely true that specialized protective garments have still to be devised and developed empirically, nevertheless since Count Rumford’s day there has been a steady progress in the scientific study of clothing.

The most notable contribution came from Max Rubner and his school some thirty years ago.3 The Munich workers systematized those clothing properties having physiological and hygienic significance and made many observations on the comparative value of different fabrics under a variety of conditions. But for the most part these valuable studies were concerned with clothing materials off rather than on the human subject. Here it may be of interest to note that the most remarkable nonsense written under the guise of science has come in this field from Nazi Germany, where the study of textiles has been pursued by interested parties as a racial issue—thus wool is said to be “superior” to synthetic fabrics because the ancient Teutons were a “wool-people.”4

After Rubner an advance was made by Hill, who was able to assess the value of garments for particular purposes (e.g., for shipwrecked sailors) without recourse in the first instance to prolonged testing on the human subject5; his katathermometer could be provided with a wet or a dry clothing surface, and its rate of heat loss was easily measurable. Rubner, who combined so well the pursuit of pure and applied science, was also a pioneer in the study of heat regulation of the human subject. It is this branch of physiology which of recent years has undergone a notable advance, due mainly to refinements in technique in the laboratories of du Bois, Bazett, and specially of Winslow and his colleagues.6

The latter have established not only the principles but many of the quantitative data of heat regulation in relation to a wide range of environmental conditions. With their data, and particularly their methods, the thermo-regulatory role of clothing can be understood in a fairly exact way. It is now possible also to formulate the insulation requirements of clothing for a variety of external air and radiant temperatures, taking into account also the level of heat production due to work.7 Studies on the physiology of clothing have also been proceeding in the London School of Hygiene.8 Such studies are making practicable the establishment of rational standards of clothing at least as regards thermal properties. But far more than is the case with nutrition, thermal insulation standards can be only a rough guide when applied to individual requirements.

As a basis for clothes rationing such standards would have to be greatly modified by hygienic considerations—necessity for changes of clothing for cleanliness, durability, special clothing for work, etc.—as well as by social factors which affect the range and variety of clothing. Nevertheless, the need to take clothing into account (e.g., in budgetary surveys) is well appreciated by social investigators, although this has to be done on a quite arbitrary basis.9 The objective evaluation of clothing might well prove of value also in connexion with social surveys of such diseases as rheumatism and tuberculosis. As in the case of food, income level has a definite influence on the amount and type of clothing bought.10 Even if it were desired to use as a reference line the warmth requirement with regard to, say, the coldest prevailing air temperature and wind of particular localities, in practice a further problem would still face the field worker: this is the actual assessment of the probable insulating power of the garments when worn. The value of easy measurements such as thickness, or weight per unit of surface area, as guides in this direction requires careful consideration.

In the laboratory the assessment and comparison of fabrics on a physiological or near-physiological basis is a more practicable proposition, particularly with the data provided by the newer studies of thermal regulation of the human subject. Such investigations have of course been pursued by a large number of workers, particularly since Rubner’s time,11 and they are to-day assuming a greater importance. The introduction of many new and cheap synthetic textile fibres demands that comparisons with the time-honoured fibres be conducted largely on a more.exact physiological and hygienic basis. For the comparison of fabrics much attention has of course to be focused on their heat-retaining properties; but the reactions of the fibre and the fabric to moisture are also of importance, not only with regard to manufacture but physiologically as well.

In the latter field a number of questions remain largely unanswered. There is the question of the moisture diffusion permeability of clothing since evaporative cooling is an important channel of heat dissipation. Of more interest, perhaps, is the old-standing problem of the moisture regain properties of different fibres. The heat of “sorption” in relation to, say, resting heat production is a significantly large amount when garments are transferred from atmospheres of a low to one of high humidity12 and the time relations are of the right order.13 But these are studies on the isolated materials. On the human subject there is little doubt that these effects would be significantly altered by the humidity levels and gradients prevailing in the garments as worn. This stresses again the primacy of physiological investigation for providing a sure basis for the scientific study of clothing.

References:

  1. Wolf, A.: A History of Science and Technology and Philosophy in the Eighteenth Century, p. 42. London: George Allen and Unwin Ltd., 1938.
  2. Hill, L.: British Medical Journal, 1942, 2, 524.
  3. Handbuch der Hygiene, 1911.
  4. Kroner, W.: Warum Wolle? Berlin, 1937.
  5. Hill, L. and Campbell, J. A.: “The Katathermometer in Studies of Body Heat and Efficiency,” M.R.C. Report, H.M.S.O., 1923, p. 179.
  6. John B. Pierce Lab Hyg., Collected Papers, 1934-9, Vol. I.
  7. Gagge, A. P., Burton, A. C., and Bazett, H. C.: Science, 1941, 94, 428.
  8. Annual Report, London School of Hygiene and Tropical Medicine, 1941.
  9. University of Bristol Social Survey: “The Standard of Living in Bristol,” 1938.
  10. Nystrom: Economics of Consumption, Chap. XIV.
  11. Black, C. P., and Matthew, J. A.: J. textile Inst., 1937, 1, 197.
  12. Nelbach, J. H., and Herrington, L. P.: Science, 1942, 95, 387.
  13. Cassic, A. B. D.: J. textile Inst., 1940, 31. 17.

This article was published in British Medical Journal, on 20 Feb 1943.