Date:
October 29, 2026
Source:
Wiley
Summary:
Getting more daylight could be linked to a surprisingly powerful benefit for brain health. In a study of more than 87,000 adults, researchers found that higher daytime light exposure was associated with a 16% lower risk of dementia, with longer exposure to bright light linked to even greater reductions. Remarkably, getting less than 42 minutes of bright daylight daily was a stronger predictor of dementia than six established risk factors.
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Could the amount of daylight you get each day offer clues about your risk of developing dementia? A large new study suggests that exposure to brighter daytime light is associated with a lower likelihood of developing the condition.
The findings, published in General Psychiatry, point to daytime light exposure as a potentially overlooked factor in brain health.
Brighter Daylight Linked to Lower Dementia Risk
To investigate the connection, researchers analyzed data
To investigate the connection, researchers analyzed data from 87,577 adults who wore wrist devices equipped with accelerometers. The devices allowed scientists to measure participants’ exposure to light during both the day and night. Over a median follow-up period of 8.1 years, 741 participants developed dementia.
The results revealed a notable pattern. People exposed to average daytime light levels exceeding 1,000 lux (a moderately bright light level equivalent to an overcast day outdoors) had a 16% lower risk of developing dementia. Spending longer periods in even brighter daytime light (at least 5,000 lux) was associated with further reductions in risk.
Too Little Daylight Emerges as a Surprising Dementia Risk Indicator
One of the most striking findings involved people who received very little bright light during the day. Getting less than 0.7 hours, or 42 minutes, of bright daytime light daily was a stronger predictor of dementia than 6 established dementia risk factors.
Interestingly, researchers found no statistically significant connection between
Interestingly, researchers found no statistically significant connection between nighttime light exposure and dementia risk. This suggests that daytime brightness, rather than light exposure at night, may be particularly relevant to the relationship identified in the study.
“Daytime light exposure may serve as a novel indicator of dementia risk,” said corresponding author Hongliang Feng, PhD, of Guangzhou Medical University, in China.
Although the findings reveal an association, they do not establish that getting more daylight directly prevents dementia. Instead, the research highlights daytime light exposure as a potentially valuable indicator of dementia risk that deserves further investigation.
Materials provided by Wiley. Note: Content may be edited for style and length.
- Nana Zheng, Wei Wang, Biao Li, Xionge Mei, Yue Liu, Jing Du, Ngan Yin Chan, Joey W. Y. Chan, Xiaoman Xing, Xiao Tan, Christian Benedict, Yun Kwok Wing, Jihui Zhang, Hongliang Feng. Associations between wearable‐device‐measured daytime and nighttime light exposures and dementia risk: A prospective cohort study. General Psychiatry, 2026; 39 (3) DOI: 10.1002/gps3.70039
Wiley. “Less than 42 minutes of bright daylight linked to higher dementia risk.” ScienceDaily. ScienceDaily, 29 October 2026. <www.sciencedaily.com/releases/2026/10/261028232707.htm>.
Wiley. (2026, October 29). Less than 42 minutes of bright daylight linked to higher dementia risk. ScienceDaily. Retrieved October 29, 2026 from www.sciencedaily.com/releases/2026/10/261028232707.htm
Wiley. “Less than 42 minutes of bright daylight linked to higher dementia risk.” ScienceDaily. www.sciencedaily.com/releases/2026/10/261028232707.htm (accessed October 29, 2026).
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