A recent study has concluded that staying in artificial lighting for a prolonged period could result in muscle loss and early signs of osteoporosis.
As a part of the study, mice were kept under constant artificial lighting for a period of months, the results were alarming.
“Our study shows that the environmental light-dark cycle is important for health,” said Johanna Meijer of Leiden University Medical Centre in the Netherlands. “We showed that the absence of environmental rhythms leads to severe disruption of a wide variety of health parameters,” he added.
Those parameters included pro-inflammatory activation of the immune system, muscle loss, and early signs of osteoporosis.
The physiological changes observed by the researchers indicated of “frailty” which is seen in humans or animals as they age.
“The good news is that we subsequently showed that these negative effects on health are reversible when the environmental light-dark cycle is restored,” Meijer said.
To study the relationship between a loss of the light-dark cycle and disease, researchers exposed mice to light around the clock for 24 weeks and measured several major health parameters.
Studies of the animals’ brain activity showed that the constant light exposure reduced the normal rhythmic patterns in the brain’s central circadian pacemaker of the suprachiasmatic nuclei (SCN) by 70 per cent.
The disruption to normal light and dark patterns and the circadian rhythm led to a reduction in the animals’ skeletal muscle function as measured in standard tests of strength.
Their bones showed signs of deterioration, and the animals entered a pro-inflammatory state normally observed only in the presence of pathogens or other harmful stimuli.
After the mice were returned to a standard light-dark cycle for two weeks, the SCN neurons rapidly recovered their normal rhythm, and the animals’ health problems were reversed.
The findings suggest that more care should be taken in considering the amount of light exposure people get, particularly those who are ageing or otherwise vulnerable.
The study was published in the journal Current Biology.