Controlled studies have demonstrated that light supplementation benefits circadian entrainment, sleep and mood. Translating these findings into effective, real-world usage of light supplementation is, however, challenging because naturalistic and supplemental light exposure are shaped by personal habits and environmental light conditions. Bridging this translation gap is especially critical for older adults, given the reduced ocular light sensitivity associated with natural ageing, which exacerbates low daytime indoor light exposure in urban housing. We therefore set out to investigate the determinants of self-directed light supplementation in this population, and what the real-world feasibility and efficacy of daytime light supplementation is. We recruited 202 participants (63-92 years; 139 females) to our interventional, prospective, randomised study in three major EU cities at different latitudes (Amsterdam, Bologna, Tartu). Participants underwent a 2-week baseline assessment of light exposure, rest-activity patterns and sleep through wearables and daily diaries. Participants were then randomised to either 12 weeks of self-implemented indoor light supplementation using a lamp placed in their most frequently used room (> 8000 melanopic EDI, N = 98) or a no-intervention group. A subsequent 2-week reassessment showed that greater naturalistic light exposure was associated with increased daytime activity, consolidated wakefulness, better subjective sleep quality, and reduced metabolic disorder incidence. Individuals with lower naturalistic light exposure self-initiated earlier and longer indoor light supplementation across seasons, in which supplementation onset before 10:00 was associated with greater daytime activity and lower rest-activity fragmentation. These results confirm that this simple, non-pharmacological, and low-cost intervention has broad potential to support healthy ageing in urban settings.
- ENLIGHTENme: Translating the Benefits of Self-Administered Daytime Light Supplementation to Older Adults in the Real World
- Débora B Constantino (Corresponding Author) - University of Surrey, School of BiosciencesFlavia Baccari - IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Epidemiologia e Statistica, Bologna, ItalyLeonardo Caporali - IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, ItalyValerio Carelli - Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, ItalyGiulia Amore - IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, ItalyMarijke Gordijn - Chrono@Work, Groningen, the NetherlandsToomas Haller - Institute of Genomics, University of Tartu, Tartu, EstoniaChiara La Morgia - University of BolognaAnne Landvreugd - Department of Biological Psychology, Faculty of Behavior and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the NetherlandsMarina Marinelli - IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Epidemiologia e Statistica, Bologna, ItalyDavid McDaid - Care Policy and Evaluation Centre, Department of Health Policy, London School of Economics and Political Science, London, UKMonika Nõmm - University of TartuFrancesco Nonino - IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Epidemiologia e Statistica, Bologna, ItalyMartina Romagnoli - IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, ItalyMartino Schettino - IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Epidemiologia e Statistica, Bologna, ItalyCorrado Zenesini - IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Epidemiologia e Statistica, Bologna, ItalyMeike Bartels - Department of Biological Psychology, Faculty of Behavior and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the NetherlandsDebra J Skene - University of Surrey, School of BiosciencesDaan R van der Veen (Corresponding Author) - University of Surrey, School of Biosciences
- Journal of Pineal Research, Vol.78(5), e70174
- Wiley
- 02/09/2026
- 09/2026
- 14/07/2026
- University of Surrey (United Kingdom, Guildford)
- The authors are deeply grateful to all the people from Amsterdam, Bologna and Tartu who generously participated in the ENLIGHTENme study as unpaid volunteers. The authors are also grateful to the overall PI of the ENLIGHTENme study, Professor Simona Tondelli and her team. This work was supported by the European Commission under the Horizon 2020 Research and Innovation Programme (EU H2020-SC1-2020-Two-Stage-RTD) through the ENLIGHTENme project, ‘Innovative Policies for Improving Citizens' Health and Wellbeing Addressing indoor and Outdoor Lighting’ (Grant Agreement No. 945238), and by the University of Surrey Doctoral College.
- 991154594002346
- © 2026 The Author(s). Journal of Pineal Research published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
- School of Biosciences
- English
- Journal article
- All data are available in the main text or the Supporting Information. The data sets analysed during the current study are available from the corresponding authors upon reasonable request.