Dark days and bright nights wreck your innate immune system and create chronic, low grade inflammation. This paper lays it all out. Your circadian system controls leukocyte trafficking, cytokine production and inflammatory responses. When disrupted (by artificial light at night/ALAN, shift work or social jet lag and flattened circadian rhythm from darker days), you get rewarded with chronic low grade inflammation and weakened immunity. Artificial light at night, EVEN DIM LIGHT at night (less than 5 lux) suppresses melatonin, desynchronizes clock genes (BMAL1, REV-ERBα, CLOCK, PER/CRY) in your master clock the SCN and peripheral immune cells, impairs monocyte/T-cell rhythms and boosts inflammatory cytokines (↑ IL-6, TNFα, IL-1β). When you do this chronically (dark days bright nights) you create LPS induced inflammation, accelerate atherosclerosis (more macrophage infiltration), promote tumor growth/metastasis (lower NK cells) and increase infection susceptibility. Genetic clock knockouts (e.g., Bmal1 deficiency) amplify ROS production and blunt antioxidant defenses (NRF2). What does all that really mean? You decrease immune efficiency or power and get a higher cancer risk and poorer outcomes in infections. So what can you do to fix this? Follow the Blue Light Diet principles of course duhhh Realize artificial light at night is immune system poison and block ALL blue/artificial light shortly after sunset (full blue blockers and redish night coded bulbs and low lux night light or no screens) to protect melatonin and immune cell rhythms. Maintain strong light and dark consistency at the appropriate time (bright days and dark nights). Take multiple sun breaks throughout the day and use blackout curtains at night if you must (see my fav in the reply below). Anchor with strong morning light. Get sunlight or red/NIR and Bright light therapy within 30 to 60 min of waking to reset your SCN and downstream immune clocks. Eat with the sun or practice chrononutrition. Daylight only eating window to further support immune and metabolic rhythms. Dont eat when its dark. Check out my fav tools below ok bye