This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
As a stimulant, alcohol acts primarily upon the nervous system and the circulation, although it increases the functional activity of many organs in the body, and gland secretion may be promoted by its use. The influence of alcohol upon the nervous system in moderate doses is to quicken the transmission and enhance the effect of nerve currents, accelerating slightly the heart action and, to a lesser degree, the respiration, while the mental processes are stimulated in part by its direct influence upon the cerebrum, and in part also by the greater rapidity of the circulation.
If alcohol is given in large doses at frequent intervals, it may overstimulate the heart, which subsequently becomes exhausted as the result of the stimulation. This is sometimes true of the senile heart.
Alcohol used within physiological limits tends to remove muscular fatigue and to increase the force of muscular action.
In the training of athletes for contests in rowing, sparring, and other sports, alcohol is usually absolutely forbidden, and it is believed that the breakdown in health which by many athletes is ascribed to overwork is not infrequently due to violations in regard to the simple physiological laws of the effect of alcohol which the accompanying features of a "sporting" life tempt them to infringe. The question is well stated by Ringer, who says: "There can be no doubt that healthy persons capable of the fullest amount of mental and physical exercise without the stimulation of alcohol not only do not require it, but are far better without it." But, as he remarks, the statement applies to the continued use of strong alcoholic spirits, and not to beers and light wines which, in addition to the alcohol, contain other ingredients which may be serviceable as food. In the latter form of beverages the quantity of alcohol is comparatively small, and the constant use of them is found, by the practical experience of many persons whose occupations preclude them from abundant exercise in the open air in the country, to improve their digestion and enable them to sustain various functions of the body which would otherwise be impaired by their mode of life.
This is especially true of elderly people and those who suffer from insomnia and retardation of gastric digestion. Experiments to test the sustaining power of alcohol were made upon three regiments of the British army and reported in 1899. The men were subjected to fatiguing exercises. To one regiment a ration of whisky was allowed, to a second a ration of malt liquor, and to the third no alcohol. The men taking whisky exhibited more energy for about four days than either of the other groups, but then became fatigued and weak; whereas those taking none steadily gained in endurance, and those taking malt liquor showed an intermediate condition. As a result of these experiments, the use of liquor was absolutely forbidden in Kitchener's Soudanese campaign, which was characterised by remarkable immunity from disease in the desert.