Cell phone use at night

Nighttime phone use can interfere with sleep and may affect mood and learning, so avoid it when possible; if you do use your phone, reduce its brightness and use a red screen filter. 1

• Bright light at night: Bright exposure between about 11 p.m. and 4 a.m. can suppress dopamine release and impair learning, with possible negative effects on mood. Occasional exposure is less concerning than making it a regular habit. 2
• Phone content: Stimulating or stressful content can also keep the mind activated at night; one guest described avoiding work calls and other stimulating activity as part of winding down. 3
• Red light: Dim red lighting or red-lens glasses are suggested as ways to reduce exposure to bright, short-wavelength artificial light in the evening. 4 5
• Phone red filter: A phone’s accessibility color-filter settings can be configured to switch the display to red with a triple-click shortcut. 6