Doctors warn how dangerous blue light exposure is to sleep quality, brain health
In this DML Report…
A new study from the American Cancer Society, analyzing data from over 122,000 people across 35 U.S. states and Puerto Rico, found that using phones late at night disrupts sleep cycles and harms brain function. The research, published on March 27, shows that regular pre-bed screen time cuts weekly sleep by about 50 minutes and increases the likelihood of poor sleep quality by 33%. This stems from blue light exposure, which delays melatonin release—a hormone critical for regulating the body’s 24-hour circadian rhythm—keeping users alert when they should be winding down.
The study surveyed participants on their device use an hour before bed, bedroom light levels, and sleep patterns, ranking sleep quality from very poor to very well. Results revealed that over 70,000 of the 122,058 participants identified as early risers, yet those using phones late still reported worse sleep, linked to disrupted REM cycles essential for cognitive health. Sleep deprivation from this habit affects brain areas tied to memory, attention, and emotional regulation, leading to fatigue, mood swings, and impaired judgment, with researchers noting a clear connection to circadian rhythm disruption.
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Light exposure at night, particularly blue light from screens, was pinpointed as the primary culprit, tricking the brain into thinking it’s daytime and reducing sleepiness. The study’s data showed that consistent late-night phone use compounds these effects, with participants losing significant rest over time. Researchers warn this common habit could have long-term health impacts, urging people to limit screen time before bed to protect sleep quality and overall brain function.