Across the United States, the night sky is no longer truly dark, and the change is showing up in Americans’ health. Studies connecting artificial light at night to sleep disruption and weight gain are now adding early evidence of cardiovascular stress. The findings apply to all sources of nighttime illumination—not just screens—so families can take practical steps at home to restore darkness.
From bright cities to desert darkness
Writer Craig Childs documented the stark contrast between urban glare and true night sky during a nine‑night bicycle trip from Las Vegas into the Mojave Desert. Starting in a heavily light‑polluted area rated near the top of the Bortle scale, he traveled roughly 200 miles north and observed the sky gradually shift from a ceiling‑like glow to a deep, star‑filled horizon. Childs’ journey, which inspired his book The Wild Dark, highlights the growing awareness among researchers, lawmakers and astronomers of the need to measure and, where possible, reverse light pollution.
How quickly the night is brightening
A 2023 citizen‑science study tracking observations from 2011 to 2022 estimated that sky brightness visible to the human eye is increasing about 9.6% per year worldwide. If that rate continues, brightness could double in roughly 7½ years, though the estimate reflects the participating observation sites rather than a universal forecast. A 2016 global atlas already showed that more than 99% of the populations of the United States and Europe live under light‑polluted skies, and nearly 80% of North Americans can no longer see the Milky Way.
LED lighting has not eliminated the problem; in many regions total outdoor illumination continues to expand. Satellites and other orbiting objects now add another source of artificial brightness, according to a major 2026 review of artificial‑light research.
Health implications emerging
At a November 2025 cardiology conference, researchers presented a preliminary study of 450 adults that combined brain imaging with satellite‑derived nighttime‑light data. Participants exposed to higher levels of ambient light showed greater brain stress activity and signs of arterial inflammation. The authors emphasized that the work is observational and has not established cause‑and‑effect, but they urged further investigation of nighttime light alongside other environmental exposures such as air and noise pollution.
Another observational study followed 43,722 women for five years. Those who slept with a light or television on were 17% more likely to gain at least 11 pounds compared with women who slept in darkness. While the mechanism was not directly tested, researchers suggested that disrupted circadian rhythms and altered melatonin signaling could play a role.
Simple steps families can take
Even when blinds are fully closed, gaps around the edges let light seep in. Blackout curtains can block most of this intrusion, though performance varies by fabric and installation. For outdoor lighting, choosing warmer‑color LEDs can reduce short‑wavelength exposure, but direction, intensity and duration matter most. Properly aimed motion‑sensor fixtures paired with lower brightness settings can limit how long lights stay on through the night. Small indicator lights on appliances are often noticeable in a dark bedroom; covering or unplugging them is an inexpensive way to reduce unwanted illumination.
Policy moves and community action
Several governments are addressing light pollution through legislation. Mexico has added light‑pollution provisions to its federal environmental law, and France regulates artificial‑light emissions through its Environmental Code. Maine enacted a statewide outdoor‑lighting law in 2026 that sets standards for public lighting installed or replaced after October 1. In the United States, the Senate unanimously passed a bipartisan resolution on April 29 recognizing National Dark Sky Week, with senators from Arizona, Nevada and Utah among the sponsors.
Dark Sky International certified its 250th International Dark Sky Place in 2025, marking the milestone with the designation of Lapalala Wilderness in South Africa. In the United States, the Grand Canyon remains a premier spot where visitors can still see a remarkably dark sky and the Milky Way on clear, moonless nights.
Why it matters for families
Restoring true darkness is not just an aesthetic concern; it directly supports healthier sleep, weight management and cardiovascular health—issues at the heart of strong families and thriving communities. By making modest adjustments at home and supporting sensible lighting policies, Americans can help reclaim the night for future generations.
Original reporting: KTBS 3 (Shreveport) — read the source article.
