Effect of light on the physiological activities of the human body

Abstract

Light is one of the environmental conditions and factors that have a direct and indirect effect on living organisms such as: animals and plants. Light not only effected directly on Physiological, food making, and living creatures grow activities, but it has its own effect on human being lives as well. Aim of this article is to examine the effects of sunlight (increase and decrease) on the human psyche.As a result of this research, it became clear that whenever the amount of light decreases from a certain limit, in autumn and winter, it causes seasonal depression in many people. It means that, the reduction of sunlight causes mental illnesses such as: stress and anxiety, and in addition to excessive use of sunlight causes skin diseases, especially skin cancer.