A new real-world study by neuroscientists at the University of Manchester shows that getting more bright light during the day can improve how well your brain works. This includes faster reaction times, better attention, and feeling less sleepy.
The study, published in the journal Communications Psychology, is the first to look at how light exposure in daily life—not just in labs—affects thinking skills. It also found that not only does brighter light help, but so does getting steady light throughout the day, with fewer changes between light and dark.
The researchers studied 58 adults over seven days. Participants wore special wrist devices that measured the amount and timing of light they were exposed to. They also used a smartphone app called Brightertime, developed at the University of Manchester, to track how their thinking ability responded to light during daily life.
The results were clear: people who were exposed to brighter daytime light had better focus and could respond 7–10% faster on reaction-time tests. They also reported feeling less sleepy and more alert.
Interestingly, people who had earlier bedtimes were more sensitive to changes in light. Under bright morning light, they stayed awake and alert better than people who went to bed later. Under dim evening light, they also became sleepier more easily.
Lead researcher Dr. Altug Didikoglu explained that both short-term and long-term light exposure helped people think more clearly. People who had regular habits—going to bed earlier and being exposed to light more consistently—did better on attention tasks.
One of the tests asked participants to find a target object in a visual search task. Those who had steady and strong light exposure during the day performed better. Fewer sudden switches between light and dark during the day also helped improve their brain performance.
The study also found that the time of day or how long a person had been awake didn’t have as much impact on their brain performance as the light they were exposed to. In other words, light had a bigger effect than simply being tired or awake at a certain hour.
The reason light affects us this way has to do with special cells in the eye. These cells are part of something called the ipRGC system in the retina—the thin layer at the back of the eye. These cells are not for seeing images but are sensitive to light, especially blue-green light. They help regulate body rhythms, mood, and alertness.
Forty-one participants also visited a lab to have their eyes tested under different lighting conditions. This helped scientists compare how people perceived light versus how much light they were actually exposed to. However, the lab tests didn’t directly predict real-life cognitive effects.
This new research shows that bright, steady light during the day may play a key role in supporting brain health, especially attention and alertness.
Dr. Altug said that even though past studies in controlled lab settings have shown the effects of light on the body clock and sleep, this study adds something new—it shows that light also matters in the real world, during normal daily routines.
The study also serves as a reminder that while artificial light at night can disrupt sleep and delay the body’s internal clock, natural light during the day is just as important for keeping the brain working well.
These findings could have important uses in places where people work under low light, during long work shifts, or at night. Making sure people get bright, steady light during the day may help improve thinking, safety, and work performance.
If you care about dementia, please read studies that eating apples and tea could keep dementia at bay, and Olive oil: a daily dose for better brain health.
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