Along with eating right and exercising, people should consider adding another healthy habit to their list: turning out the lights. That's according to a new study showing many negative health consequences for mice kept under conditions of constant light for a period of months. The study shows that the environmental light-dark cycle is important for health, because the absence of environmental rhythms leads to severe disruption of a wide variety of health parameters. Those parameters included pro-inflammatory activation of the immune system, muscle loss, and early signs of osteoporosis. The researchers say that the observed physiological changes were all indicative of "frailty" as is typically seen in people or animals as they age. But there was some more encouraging news, too. The good news is that study subsequently showed that these negative effects on health are reversible when the environmental light-dark cycle is restored. http://www.eurekalert.org/pub_releases/2016-07/cp-ial070716.php