If you think about improving your health, you probably think about diet, sleep, and exercise, but do you ever think about light? A new study in the UK suggests that light-driven disruption can lead to a higher risk of premature death. The study had nearly 90,000 people wear wrist-worn light sensors and analyzed the risk of dying in the next eight years. Participants exposed to the most light at night had a 21% to 34% higher risk of premature death. People who had the brightest days had a 17% to 34% lower risk of premature death than those who had low light exposure during the day. According to the study’s lead author, Daniel Windred, the data highlights an "emerging risk factor for poor health and longevity". Previous studies previously linked mortality and light exposure, however, the UK study is the first to measure personal lighting 24 hours a day.