Most people think that getting enough hours of sleep is all that matters for good health. But new research suggests that what your bedroom is like during those sleeping hours may also matter. Even low levels of light at night could potentially affect the heart and increase cardiovascular risk.
A recent study found that people exposed to light while sleeping showed changes in the structure and function of the heart compared with those who slept in near darkness. Researchers examined exposure to around 3 lux of light, a level that can be comparable to dim outdoor light or light entering a bedroom through a door or window.
How nighttime light may affect the heart
The researchers observed greater thickening of the walls of the left ventricle among people exposed to more nighttime light. The left ventricle is the main chamber responsible for pumping oxygen-rich blood throughout the body.
This condition, known as left ventricular hypertrophy, can make the heart work less efficiently and has been associated with serious cardiovascular problems, including heart failure and abnormal heart rhythms.
Researchers believe nighttime light may also interfere with the body’s natural circadian rhythm. This internal biological clock helps regulate sleep, hormones and other important processes.
You may not realize how much light is in your room
You do not necessarily need to sleep with a bright lamp switched on for nighttime light exposure to become an issue. Light can come from streetlights outside the window, electronic devices, hallway lighting, television screens or even small indicator lights on household appliances.
A bedroom may appear dark to you while still containing enough light to affect the sleeping environment.
The easy fix
The good news is that reducing nighttime light is relatively simple. Experts recommend using blackout curtains or blinds, covering bright electronic indicator lights and switching off unnecessary lights before going to bed.
A sleep mask can also be useful if completely darkening the bedroom is difficult. Using softer, warmer lighting before bedtime may also create a more sleep-friendly environment.
Better sleep starts with a darker bedroom
Creating a dark sleeping environment does not guarantee protection from heart disease, and the study does not prove that nighttime light directly causes cardiovascular disease. However, reducing unnecessary light is a simple habit that may support healthier sleep and circadian rhythms.
The bottom line
Your sleep routine involves more than simply getting enough hours in bed. Keeping the bedroom as dark as comfortably possible may be another small step toward better sleep and cardiovascular health.
If you have heart disease, high blood pressure or other cardiovascular concerns, maintaining healthy sleep habits should be part of your broader approach to protecting your heart.
