Nighttime lighting in the UK linked to changes in the heart
Researchers who analyzed data from participants in the UK Biobank project found an association between exposure to light at night and structural changes in the heart. People who regularly slept in the presence of lighting had thicker heart walls, and the organ pumped blood less efficiently, TIME reports.
Sensor data and MRI
The study authors used information from fitness monitors that some UK Biobank participants wore for a week. The devices were equipped with light sensors, making it possible to objectively measure illumination levels, unlike previous studies that relied mainly on participants’ self-assessments.
The scientists then evaluated the results of cardiac magnetic resonance imaging performed after the monitors were worn and before participants developed diagnosed heart problems. They compared people with minimal exposure to light at night with those who regularly slept with lighting of at least 3 lux. This level roughly corresponds to the light from three candles placed about 90 centimeters away.
More current news is available on the UA.News Telegram channel Telegram.
The association does not prove causation
In the nighttime-lighting group, MRI showed thicker heart walls and lower efficiency of its pumping function. According to Lu Qi, a professor of epidemiology at Tulane University, these changes do not in themselves mean the presence of heart disease, but they precede its development.
The study is correlational in nature, so it does not make it possible to fully rule out the influence of other factors that may be associated with both light at night and heart condition. At the same time, its findings add to previous observations that linked nighttime lighting to higher rates of diabetes, obesity, hypertension, heart failure, and other cardiovascular problems.
The researchers did not establish the exact source of light recorded by the sensors: it could have been lighting in the room or another part of the house, a switched-on television, a tablet, or another screen. The results of these studies indicate that the bedroom should be made as dark as possible.
