ENLIGHTENme: Translating the Benefits of Self-Administered Daytime Light Supplementation to Older Adults in the Real World

Débora B Constantino and colleagues recruited 202 adults aged 63 to 92 years in Amsterdam, Bologna, and Tartu. After a two-week baseline with wearables and diaries, participants were randomized to 12 weeks of self-implemented indoor light supplementation using a lamp above 8,000 melanopic EDI or to no intervention. A two-week reassessment followed. Lower naturalistic light exposure was associated with earlier and longer lamp use. Starting supplementation before 10:00 was associated with greater daytime activity and less rest-activity fragmentation. The study also reported associations between naturalistic light exposure, consolidated wakefulness, subjective sleep quality, and lower incidence of metabolic disorders. The trial addresses feasibility in real living conditions rather than a tightly controlled laboratory dose. It does not show that light extends life, reverses biological age, or prevents dementia. Some outcomes were observational associations within an intervention study, and the intervention was self-administered. The authors disclose patents related to light supplementation, and one company involved in melatonin analysis is directed by a study author. Bright light can be inappropriate for some eye or psychiatric conditions. The finding supports daylight and carefully designed light exposure as a practical health behavior, not a longevity supplement or a replacement for medical care.

These results confirm that this simple, non-pharmacological, and low-cost intervention has broad potential to support healthy ageing in urban settings.