Spending More Time Outside Could Reduce Dementia Risk

Sun Rays: Spending time outside is linked to a multitude of health benefits: studies show that a single trip to the woods reduces cortisol levels for a week and that nature is a major mood-booster. New research bolsters the evidence supporting nature as a brain-health boon, showing that daylight exposure could be a key in dementia prevention.

The Study: Researchers analyzed data from 87,577 adults in the UK Biobank who wore wrist devices that continuously measured their daytime and nighttime light exposure. Participants were followed for a median of 8.1 years, during which 741 people developed dementia. Higher daytime light exposure was associated with a lower risk of dementia. Average daytime light levels above 1,000 lux (roughly equivalent to an overcast day outdoors) were associated with a 16% lower dementia risk, while spending more time in very bright light (at least 5,000 lux) was linked to even greater protection. Getting less than 42 minutes of bright daylight per day emerged as a stronger predictor of dementia than established risk factors.

The Takeaway: Increasing daytime exposure to natural light could become a simple, low-cost strategy to support cognitive health.

Keep in Mind: Because this was an observational study, it cannot prove that daylight directly prevents dementia. However, the findings support growing evidence that healthy circadian rhythms play an important role in brain health.