Health, Science, Life

July 13, 2009

How Much Do We Weigh?

Do you know how much you weigh? Do not think this question to be very simple even if you have weighed yourself quite recently. Have you any idea how your weight varies during a day, by the evening, in an hour or even in ten minutes?

The weight of a human body is constantly fluctuating. Apart from quite obvious causes such as meals, when our weight increases spasmodically, there are others that bring about constant, slow, quite unnoticeable variations. The first to detect them was Sanctorius over 300 years ago. He constructed huge scales and spent hours, observing how his own weight changed. The results of this experiment were so surprising that numerous visitors gathered in his laboratory to see the eminent scientist lose weight in their presence. The changes were appreciable: overnight Sanctorius lost as much as a kilogram.

One can lose weight for various reasons. Loss of carbon dioxide alone accounts for a reduction of 75 to 85 grams over a period of twenty-four hours. This is only a trifle compared with the loss of water via the lungs which amounts to 150 to 500 grams in twenty-four hours, the quantity lost by perspiration being still greater. A man is constantly perspiring, although sweat does not run from his body in large drops.

From the openings in the numerous sweat glands scattered over the surface of the skin minute drops of sweat are exuded which can be seen only through a microscope. If the air is dry, they evaporate before new ones are discharged from the glandules, and the skin remains dry. In cold weather between 250 and 1700 grams of water are evaporated through the skin. A man doing hard physical work in dry hot weather exudes as much as 10-15 litres of sweat over a period of twenty-four hours, and sometimes as much as four litres, an hour. Even in this case, however, the skin may also remain dry. According to moderate estimations, people living in the southern regions secrete between 70 and 150 tons of sweat in the course of a seventy-year lifetime. This is enough to fill three large railway tank wagons.