睡觉时卧室不够黑，心脏可能先知道：一项万人研究发现了早期信号
Your Bedroom May Be Working Against Your Heart Health—and You Might Not Even Notice It
Women's Health 报道了一项发表在《European Heart Journal》的研究：研究者分析了英国生物银行（UK Biobank）11,071 名参与者的数据，他们手腕上戴了七天光传感器记录夜间受光量，三年后接受心脏核磁共振检查。结果是：夜间受光达到 3 勒克斯以上（大约是明亮月光、或门缝透进来的光的水平）的人，左心室壁出现增厚、心腔空间变小，心肌在每次跳动时的舒展性也变差——这些被视为心脏工作效率下降的早期迹象。专家解释的机制是：大脑把光当作醒来的信号，夜间光照会打乱昼夜节律，进而影响血压、代谢等与心血管健康相关的过程；睡眠本是心率与血压下降、让心血管休息的时间。必须划清证据边界：这是观察性研究，发现的是关联、不是因果，受访专家也明确说还需要更多研究弄清机制，不能推出「住在城里、卧室有光就会得心脏病」。可落地的建议很朴素：用遮光窗帘、戴睡眠眼罩、睡前调暗家里灯光、减少睡前亮屏、关掉不必要的夜灯；目标不是追求绝对黑暗，而是减少不必要的夜间光照。这与本站一贯的睡眠建议方向一致：先睡够七小时，再把卧室做凉、做暗。
There are a few universal truths with sleep: Most people should aim to get at least seven hours of sleep a night, and you'll want to snooze in a cool, dark room. But that last part may have benefits that extend beyond your ability to log enough sleep at night, according to new research published in European Heart Journal.
The study found a link between nighttime light exposure—think: night lights, hallway lights, and street lights outside your window—and a higher risk of developing factors that could raise your odds of heart disease. It's a stretch to say that you're doomed to develop heart disease if you live and sleep in a busy city environment, but doctors say the findings make the case for doing whatever you can do to block out light at night. Here's why.
Meet the experts: Christopher Winter, MD, a sleep medicine specialist, neurologist, and author of The Sleep Solution: Why Your Sleep Is Broken and How to Fix It; Yu-Ming Ni, MD, cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA
What did the study find?
For the study, researchers analyzed data from 11,071 people who participated in the UK Biobank, a large-scale biomedical database. Participants wore a light sensor on their wrist for seven days, which measured how much light they were exposed to during the night.
After three years, the participants were asked to do cardiac MRI scans to look at the structure and function of the heart. The researchers then broke participants into two groups: Those who were exposed to nighttime light levels above three lux (similar to bright moonlight or light that seeps under a door) and those who were exposed to almost no light at night.
The researchers found that those who were exposed to at least three lux of nighttime light had thickening in the wall of the left ventricle chamber of the heart, reducing the space inside the chamber. The MRI scans also found that the heart muscle was less flexible during each heartbeat, which can be an early sign that the heart isn't functioning as efficiently as it should.
The researchers concluded that "nighttime light exposure may elevate cardiovascular disease risk and highlight dark nights and adequate sleep for cardiovascular health."
Why might light exposure at night be bad for your heart?
This isn't the first study to link light exposure at night to heart issues. Research presented at the American Heart Association's Scientific Sessions 2025 found that people who were exposed to higher levels of artificial light at night had higher brain stress activity, blood vessel inflammation, and a slightly higher risk of major heart events, including heart disease.
What's behind this link? There could be a few things going on, according to doctors. "The brain understands light as a signal to wake up," says Christopher Winter, MD, a sleep medicine specialist, neurologist, and author of The Sleep Solution: Why Your Sleep Is Broken and How to Fix It. "Light at night creates a conflict between a brain that wants to sleep and a brain getting a signal that the timing is off for that sleep."
That may interfere with the body's circadian rhythm, which helps to regulate sleep, blood pressure, metabolism, and other processes that affect cardiovascular health, according to Yu-Ming Ni, MD, cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA. "Over time, poor sleep and circadian disruption may contribute to cardiovascular risk factors such as high blood pressure, obesity, and diabetes," he says.
Sleep is also an important time for the cardiovascular system to recover: "During healthy sleep, heart rate and blood pressure generally decrease, giving the heart and blood vessels a chance to recover from the demands of the day," Dr. Ni says. "When sleep is consistently disrupted or inadequate, those processes can be affected, potentially increasing cardiovascular stress over time."
But experts stress that the study found a link between nighttime light exposure and a higher risk of heart disease risk factors—it didn't prove that one caused the other.
How to cut down your nighttime light exposure
While Dr. Winter stresses that more work needs to be done to figure out what's driving this link. Still, he says it's a good idea to sleep in the dark no matter what. Experts recommend these habits to cut down on your nighttime light exposure:
- Consider wearing sleep masks
- Use blackout blinds and window coverings
- Dim the lights in your home in the evening
- Limit bright screens before bed
- Turn off unnecessary lights at night
"The goal isn't to create perfect darkness at all costs, but to minimize unnecessary light and make your sleep environment as comfortable and conducive to sleep as possible," Dr. Ni says.
来源：颜如玉编辑台 · womenshealthmag.com