Exposure to bright light in the morning can improve brain function by helping to regulate the body’s internal clock, known as the circadian rhythm. This rhythm controls many important processes, including sleep quality, hormone release, and brain health. Morning light, especially natural sunlight or bright artificial light at about 10,000 lux, acts as a strong signal to reset this internal clock, promoting better sleep and overall brain function.
Research shows that morning light exposure can enhance sleep quality, which is crucial for brain health. Good sleep supports processes like reducing inflammation, improving mitochondrial function (the energy producers in brain cells), and enhancing the brain’s waste clearance system called the glymphatic system. These functions are important for maintaining cognitive abilities and may reduce the risk of neurodegenerative diseases such as Parkinson’s and Alzheimer’s[1].
The intrinsically photosensitive retinal ganglion cells (ipRGCs) in the eye detect light and help synchronize circadian rhythms. When these rhythms are well aligned through regular morning light exposure, the body’s systems work more efficiently together. This synchronization supports not only sleep but also metabolism, toxin filtering from the brain, and overall brain health[2][4].
In addition to improving brain function, morning light exposure can positively influence mood and mental health. Studies suggest that shifting sleep schedules earlier and getting bright light soon after waking can reduce risks of depression and anxiety. This is because being awake during the biological night, when the brain expects sleep, can impair decision-making and increase anxious thoughts. Morning light helps shift the circadian rhythm earlier, promoting better mental health[5].
It is important to avoid light exposure at night, as it can disrupt circadian rhythms and increase stress-related brain activity, which may lead to inflammation in blood vessels and raise the risk of cardiovascular and brain diseases. Sleeping in darkness supports melatonin production and healthy nighttime blood pressure drops, both beneficial for brain and heart health[3][7].
Sources
https://news.ohsu.edu/2025/11/14/ohsu-research-will-examine-effect-of-bright-light-therapy-on-brain-health
https://www.aota.org/publications/ot-practice/ot-practice-issues/2025/lighting-the-home-environment-for-circadian-health
https://www.healthline.com/health-news/light-exposure-sleep-cardiovascular-disease-risk
https://www.ahajournals.org/doi/10.1161/CIR.0000000000001388
https://lifestylemedicine.stanford.edu/staying-up-late-mental-health/
https://timesofindia.indiatimes.com/life-style/health-fitness/health-news/do-you-sleep-with-lights-on-harvard-study-warns-of-hidden-health-threats-that-could-damage-your-heart-and-brain/articleshow/125406719.cms
