Artificial light at night affects health: Study

Research by a team of scientists from the Allahabad University’s (AU) biochemistry department has found that modern lifestyle has made humans remain in artificial light even during day time. This disrupts our daily rhythm. At night, humans are frequently exposed to artificial light emitted by smartphones and computers.

The research findings provide a scientific explanation to the ill-effects of artificial light on human physiology and possibly explain the reasons for the development of oxidative stress which becomes a cause for many other diseases.

Long exposure to artificial light can cause oxidative stress—an imbalance between free radicals (unstable atoms that can damage cells, causing illness and ageing) and antioxidants (compounds that inhibit oxidation, a chemical reaction that can produce free radicals) in the body, the research found.

The team of scientists led by SI Rizvi through this study, findings of which have recently been published in the journal Chronobiology International (USA), have shown that rats made to live under artificial light develop oxidative stress.

This condition is also found in humans and is known to be a cause of major illnesses such as those of the heart, kidney and liver. It has also been found that the brain is also affected by oxidative stress, said Rizvi.

He said that if someone has the habit of waking up at 6am, he/she will get up at this time even when he/she has slept late at night. “This is because the body has an internal clock which controls our basic functions. Most important physiological parameters such as body temperature, pulse, heart rate and digestion are all governed by the body clock. The body clock is controlled by the daily period of light and dark which is dependent on sunlight and darkness. All living systems have evolved on the influence of sunlight. It is of interest that now humans have started to spend most of their time under artificial light,” he explained.

Rizvi said that rats which were given a hormonal drug called melatonin were protected from artificial light induced oxidative stress.

Melatonin is a hormone which is secreted at night by the pineal gland in the brain. The secretion of melatonin stops when the eyes sense light. It is only secreted in darkness.

The findings of the research group also proved that old rats were more prone to oxidative changes under the influence of continuous light compared to young rats.

Rizvi said that old age also contributes to the response of the body to damage caused by continuous artificial light.