Don't leave night lights on all night! Study links sleep light exposure to heart thickening and stroke risk

Subtle light during sleep might be silently altering your heart structure. A study published in the 'European Heart Journal,' involving over 11,000 participants, suggests that even light levels exceeding just 3 lux in the sleep environment may be associated with harmful changes in heart structure and function. 3 lux is roughly equivalent to a low-brightness phone screen or hallway light peeking through a door gap. Researchers had participants wear a wrist-worn light sensor for seven consecutive days. About three years later, they underwent cardiac magnetic resonance imaging. The results showed that compared to those who slept in near-total darkness, individuals with high light exposure had thickened left ventricular walls and reduced diastolic function of the heart muscle. A dose-response relationship was observed, where more light exposure led to worse outcomes. Another long-term follow-up indicated that high light exposure was linked to a 29% increased risk of heart failure, a 33% increased risk of stroke, and a 26% increased risk of cardiovascular death. The underlying mechanism is closely related to circadian rhythm disruption. Nighttime light suppresses melatonin secretion, preventing the sympathetic nervous system from fully relaxing. This disrupts the normal nocturnal dip in blood pressure and heart rate, which can lead to endothelial dysfunction and elevated inflammation levels over time. Shortened sleep duration plays a partial mediating role. Recommendations for 'light reduction' in the bedroom include: turning off unnecessary night lights, covering indicator lights on electronic devices, and using blackout curtains. If you fear the dark, consider keeping a low-position, warm-colored dim light and wearing an eye mask. Ah, I sleep with the lights off now, but my power strip has an indicator light and the AC has a display light. I can't turn those off 🤔 My curtains are also semi-transparent. Changing those would be a hassle... and I'm not used to eye masks. Oh well, I'll just leave it as it is 😑