“Every hour of sleep before midnight is worth two after midnight.” You might’ve heard this adage before, especially if you’re familiar with traditional Chinese medicine (TCM). According to traditional health practitioners in China, there’s a 24-hour body clock that governs when — and how well — our bodies function. Think of it as an Eastern take on the circadian rhythm.
In the Chinese body clock, certain organs do most of their heavy lifting at set times each day. But they can only function properly if you sleep during optimal resting times. For instance, TCM says that the “triple burner,” or Sān Jiāo (think of it as your body’s core containing your main vital organs), is busy harmonizing and generating body heat between 9 p.m. and 11 p.m. After that, the gallbladder starts producing bile, and by 1 a.m., your liver should be processing toxins and releasing fresh blood.
Given all the work your body does during the late evening and early morning hours — at least according to TCM — it seems pretty important to hop in bed early to avoid disrupting your body clock. But is it really that important to start snoozing before the clock strikes 12, or is it just a myth?
The benefits of going to bed before midnight
There might be some truth to the TCM advice to get snoozing at least a couple of hours before midnight rolls around. For one, going to sleep and rising in accordance with the sun may help regulate your circadian rhythm, since melatonin (the hormone that helps you get drowsy) peaks in the body during dark hours and decreases during daylight1. The longer you stay awake at night, the more likely you are to throw off your natural body clock, especially if you also choose to sleep in.
Additionally, there are some serious health benefits of catching ZZZs before 12 o’clock. One 2022 study concluded that people are more likely to engage in unsafe behaviors after midnight, such as self-harm, substance abuse, and criminal acts. Researchers hypothesized that brain activity is impaired at night, when the body is usually preparing itself for rest.
A 2021 study also found cardiovascular risks among those who fall asleep after midnight. Research participants who went to bed late were 25% more likely to develop cardiovascular disease, yet going to bed too early was also associated with health issues. Those who fell asleep between 10 p.m. and 11 p.m. — a window many TCM practitioners would recommend — were the least likely to suffer from cardiovascular disease.
Finally, the real kicker: Going to bed past midnight might lead to an earlier death — yikes! A 2018 study discovered that a preference for sleeping late was associated with greater morbidity compared to early bedtimes.
There might be some exceptions
Clocking a couple of hours of sleep before midnight sounds nice and all, but if you’re like some people, actually snoozing before 12 might be harder than it sounds. The truth with bedtimes — just like a lot of things — is that it’s not one size fits all. People have different chronotypes, or wake and sleep preferences, based on factors such as age, environment, and even genetics2. Fighting your body’s natural inclination might be more work than it’s worth. If you try to sleep at, say, 10 p.m. and consistently struggle to wind down, the traditional Chinese approach might just not be for you. Still, it’s crucial to make sure you get enough rest and give your body a solid seven or eight hours to restore itself each night.
The final verdict
There’s one final point worth noting before you head to bed tonight: There’s no real evidence that every hour of sleep before midnight is worth more than an hour of sleep after midnight. It’s also kind of unclear if the traditional Chinese body clock is even accurate3. Whether you ascribe to TCM or you’re just learning about it, the best approach might be to try out an earlier bedtime, in alignment with the Chinese body clock concept, to see if you notice any improvements in your health, behaviors, or mood.
Given the research, there are good reasons to conk out early, especially if you tend to not get enough sleep. But don’t worry that you’re missing out on the best sleep of the night by dozing off after midnight. Listen to your body, get the rest you deserve, and decide for yourself when’s the best time to go to bed.