Artificial light is reshaping how dogs experience night.

Dogs evolved alongside predictable cycles of daylight and darkness. Indoor lighting has altered that rhythm in homes across the United States over the past several decades. Lights stay on later, screens glow after sunset, and rooms rarely reach full darkness. Canine brains still rely on light cues to regulate sleep hormones, body temperature, and rest depth. When those cues blur, sleep becomes lighter and less restorative. Owners often notice pacing, early waking, or nighttime restlessness without realizing indoor lighting plays a role.



