For the study, neuroscientists at West Virginia University and the University of Texas at Austin recreated cardiac arrest in animal models. This temporarily disrupted the brain’s oxygen supply. Then, they divided the models into three groups that would spend their night in dim red light, dim white light, and the dark. (Related: Study finds about half of cardiac arrest patients showed these telltale signs before their attack.)
After seven days, the researchers examined the health of the models’ brain cells. They found that exposure to white light at night caused various poor outcomes.
One of these outcomes was the increased risk of death due to cardiac arrest. The researchers found that animal models in the white light group were more likely to die due to cardiac arrest. The death risk in the models in the red light group did not differ from the group that stayed in darkness.
The researchers also found that exposure to white light at night was associated with greater cell death in the hippocampus, an area of the brain responsible for memory formation, and more aggressive inflammation overall. What’s worse is that even just one dimly illuminated night was enough to cause pro-inflammatory cytokines – which are small proteins critical to immune responses – to surge.
Lead author Laura Fonken suggested that changing the light color in cardiac arrest patients’ room from broad-spectrum white to a red hue could benefit the patient.
"If this also occurs in clinical populations, then it would be important because it would not require complicated clinical trials to implement for patients and could improve recovery from various other health events that require hospital stays," said Fonken.
Fonken and her team are now looking at whether white light at night triggers a similar physiological response in people. Their study was funded by the National Institutes of Health (NIH).
Cardiac arrest is the sudden loss of heart function in a person who may or may not have been diagnosed with heart disease. It can come unexpectedly, or in the wake of other symptoms. If symptoms do occur, the person may experience a racing heartbeat or may feel dizzy.
This condition is often deadly, with over 350,000 Americans every year having an out-of-hospital cardiac arrest. Out of these people, only 12 percent survive. Therefore, appropriate steps are needed to be done when this occurs.
The ways to prevent death due to sudden cardiac arrest (SCA) may vary, depending on whether: you already had SCA; you have never had it but at high risk; or you have never had SCA and have no known risk factors for the condition.
For people at high risk for the condition, it is important to manage the risk factors right away. For people who have no known risk factors for sudden cardiac arrest, adhering to a heart-healthy lifestyle can reduce your risk for heart disease and other heart problems.