Cell phone use at night

Nighttime phone use can interfere with sleep and may affect mood and learning. Reduce the light and, just as importantly, avoid stimulating or stressful content late at night.

• Bright light from 11:00 p.m. to 4:00 a.m.: Exposure during this window can suppress dopamine release, inhibit learning, and potentially contribute to depression while awake. Even a dim phone screen may still matter late at night, when the eyes are more sensitive to light. 1
• Stimulating content: What you do on your phone can matter more than screen brightness; doom-scrolling or stressful emails may be more disruptive than enjoyable content, even with a strong blue-light filter. 2
• Red light: Dim red lighting or red-lens glasses can reduce exposure to bright artificial light in the evening. 3 4
• Phone red filter: Accessibility settings can apply a red color filter, and some phones allow a triple-click shortcut to turn it on at night. 5
• Occasional late night: A rare night of bright-light exposure is not considered a major problem; the general aim is to minimize light at night. 6

When you do use your phone at night, keep it dim, limit the time, and choose calming content.