Bright Light Therapy Improves Sleep and Activity in Older Adults

Study Shows Bright Light Therapy Supports Healthy Aging

A University of Surrey study found that bright light therapy lamps used at home improved sleep quality, increased daytime activity, and stabilized circadian rhythms in older adults living in urban areas. The study included over 200 participants aged 63–92 from Tartu, Bologna, and Amsterdam.

Participants in the light supplementation group placed lamps at head height in their most-used room and used them within one hour of waking, turning them off at least four hours before bedtime, over a 12-week period.

Real-World Evidence from a Diverse Urban Population

This was the first real-world study to test bright light therapy in everyday settings, following previous laboratory findings. The study accounted for seasonal daylight changes and included culturally diverse cities to ensure broader applicability.

All participants wore wrist actigraphy monitors and pendant light sensors to objectively measure activity and light exposure, providing detailed data on how light supplementation affected daily rhythms.

Key Findings: Timing and Baseline Light Exposure Matter

Participants with higher baseline exposure to natural light showed better sleep quality, more consolidated daytime wakefulness, and higher activity levels. Those who began light therapy earlier in the morning had less disrupted rest-activity rhythms and more daytime activity.

Finishing light supplementation earlier in the day, which reduced evening light exposure, was linked to lower rest-activity fragmentation, suggesting that both the amount and timing of light exposure are important.

Metabolic Health and Light Exposure

Initial assessments showed that participants with metabolic disorders such as high blood pressure, diabetes, obesity, or cardiovascular conditions had lower total light exposure than those without these conditions.

The findings suggest that increasing daytime light exposure may be a simple, low-cost way to support metabolic and overall health in older adults, especially those with limited outdoor mobility.

Limitations and Practical Considerations

The study was conducted in urban European cities and may not apply to rural settings or populations with different lifestyles. The intervention relied on participants' adherence to instructions for lamp use, which could affect results.

Bright light therapy is not a substitute for medical care. The study did not assess long-term health outcomes or compare light therapy to other interventions for metabolic disorders.