Over-exposure to artificial light at night has serious long-term health implications like tendency to breast cancer, obesity, diabetes, depression, and possibly other forms of cancer, says a new study.
"It's a new analysis and synthesis of what we know up to now on the effect of lighting on our health," said Richard Stevens University of Connecticut, Farmington (Uconn).
"We don't know for certain, but there's growing evidence that the long-term implications of this have ties to breast cancer, obesity, diabetes, depression, and possibly other form of cancers," he said.
Inadequate exposure to natural light during the day and overexposure to artificial light at night is not conducive to the body's natural sleep/wake cycle.
Stevens and co-author Yong Zhu from Yale University explained the known short-term and suspected long-term impacts of circadian disruption in an article published in the British journal Philosophical Transactions of the Royal Society B.
"It's become clear that typical lighting is affecting our physiology," said Stevens.
"But lighting can be improved. We're learning that better lighting can reduce these physiological effects. By that we mean dimmer and longer wavelengths in the evening, and avoiding the bright blue of e-readers, tablets and smart phones," he added.
Those devices emit enough blue light when used in the evening to suppress the sleep-inducing hormone melatonin and disrupt the body's circadian rhythm, the biological mechanism that enables restful sleep.