Effects of quantity and ouality of lights upon metabolism
[영문]Interest upon light and colors is acutely increasing recently and the regulation of lights and colors in environment is becoming an important field of life science in plants, in lower animals, and in human beings. There are a great number of articles in literature which deal with the effects of lights and colors upon life. Johnston (1936) mentioned that under the action of light, carbon dioxide and water are united in the presence of chlorophyll to form simple sugars. These sugars are elaborated into starch, proteins, organic acids, fats, and other products. Most of these compounds are foods for the plant and as well as for the animals that come to feed upon them. Further, the growth of the plant is vitally affected by the length of day, the intensity of light, and by color even more than by temperature and moisture.
Pleasanton (1946) declared that the blue color "for one of its functions, deoxygenates carbonic acid gas, suplying carbon to vegetation and sustaining both vegetable and animal life with its oxygen."
Flammarion (1961) reported the best effects for red light. He grew plants in hot houses under red, green, blue and clear glass, attempting in a crude way to equalize light intensities. Red seemed to produce taller plants but thinner leaves, blue created weak, under developed plants.
Flint(1961) found that the short waves of light-violet, blue, green-inhibited the germination of lettuce seed, but long waves of light-red-orange and yellow-promoted germination. Men and animals, like plants, may be virtually influenced by color in
their life process, their health, sickness and well being, whether or not the color is actually seen by them.
Deutch (1942) mentioned that every action of light has in its influence physical as well as psychic components and he pointed out that if the lights are thrown to one side of the body, the tension of that side is increased.
Goldstein (1942) reported that the outstretched arms of a subject will tend to deviate away from each other under the influence of a warm color such as red toward each other under the influence of a cool color such as green or blue.
Harmon (1944) mentioned that good illumination and good color are vital to child welfare in schools. Where conditions are right-without glare and extreme contrast-there is balanced posture and a straight spine. Bad conditions cause unbalanced posture, bent head tilted shoulder, muscular strains.
Birren (1961) mentioned in his book Color Psychology and Color Therapy that color has so important a role upon life that special consideration should be paid in picking the colors for mental hospital, a battleship, a missile base; to make new kinds of colored paper to print on; to make a new home attractive; to make new kinds of colored bricks for buildings; and he reduced fatigue by giving workers light green end walls in the textile mile where he was engaged. In this light, the author attempted the following experiments to evaluate the influences of quality and quantity of lights upon basal metabolism of rats.
Materials and Methods
The experiments were carried out with healthy, male albino rats, weighing approximately 250-300 grams. The animals were kept on a constant diet and the factors of environment were constant for more than one month in this laboratory; these conditions were maintained throughout the experimental period.
The metabolism of the animals was measured by modified Watts & Gourleys' apparatus for rats. The animal container with the rat was placed chamber of the above apparatus for 20-25 minutes until the animal rested quietly, then a film of soap was made across the distal end of the burette. As the rat used oxygen, the soap film was moved slowly toward the proximal direction of the burette due to the oxygen consumption by the rat, and carbon dioxide produced from the respiration of the rat was absorbed in the soda lime on the bottom of the respiratory chamber. The
time required for it to traverse the 5 ml volumes was measured with a stop watch. Five or more measurements on each animal were made on the same experimental day and mean value was calculated. The basal metabolism was calculated in terms of calories per square meter of body surface per hour by the mean oxygen consumption per hour. The animals were not fed for about 16 hours before each measurement.
Each experimental group contained 7-10 animals. The measurement was performed every other day and it was continued more than one month. Special considerations were paid to the laboratory room to avoid any possible influences from the outside and to maintain a constant environment. For illumination of the laboratory chamber,
fluorescent lights(white, red, yellow, green and blue) made by Toshiba Electrical Co. were used, and for photometry, a luxmeter made by Tajiri Industrial Co. was used.
In a dark room test, a wooden box which has one side door, was prepared for the mentioned apparatus. The apparatus was placed int eh box and the door was closed. Through the hole of the center of the door, the burette of the apparatus was protruded to be able to read the markings during the experiments. The burette was illuminated only by a pen light the head of, which was wrapped with a piece of gauze to prevent radiating lights. In color test, the walls of the laboratory were patched with colors corresponding to the illuminating color of each laboratory
1. The mean value of basal metabolism in dark room in 225 measurements on 28 normal rats kept under constant diet and factors of environment in this laboratory for more than one month, was 25.6±0.3 cal/m**2/hr.
2. The average value of basal metabolism under the different intensities(50 Lux, 100 Lux & 200 Lux) of white light were 31.2±0.7 cal/m**2/hr. 35.5±0.4 ca/m**2/hr and 39.5±0.5 cal/m**2/hr respectively. There was a significant difference in
metabolic rate in dark room and even in low intensity (50 Lux) of illumination, and it is believed that the metabolic rate of rats under the white lights seemed to be parallel with the intensities of lights.
3. Metabolic rate of rats also seemed to be related to the colors. The long wave length of light increased metabolic rate more than the short wave length of light, but the intensities of illumination of colors also influenced the basal metabolism of rats as in white light. The increments of metabolic rate by different colors were red, yellow, green and blue in order, but between green and blue there was no significant difference in metabolic rate statistically.
4. The mean value of basal metabolism under the white light occupied the intermediate zone of values of basal metabolism under the yellow and green color.