Sleeping with the blinds open increases the chance of having a stroke or heart attack.
Sleeping with the blinds open causes health problems
Light pollution disrupts the body's natural sleep-wake cycle and the lack of rest places increased strain on the heart and other vital organs.
Experts in China made the discovery after analysing data from thousands of people and have warned that around 80 per cent of Earth's population is living in light-polluted areas - meaning that they could be struggling to sleep.
Dr. Jain-Bing Wang, a public health expert who was involved in the research, said: "Our study suggests that higher level of exposure to outdoor artificial light at night may be a risk factor for cerebrovascular disease.
"Therefore, we advise people, especially those living in urban areas, to consider reducing that exposure to protect themselves from its potential harmful impact."