At 7:30 this morning, after eight hours of sleep, my alarm went off. At 8:45, I finally got out of bed. During that hour and 15 minutes, I was vaguely aware that I needed to move my body from my warm bed to the floor, but the willpower just wasn’t there. This meant that to get to work on time at 9:30, I had barely 30 minutes to get clothed, fed, and into my car on a beautiful, mild day when I really should have been biking. Like most mornings, I showed up to our daily morning meeting a couple minutes late, still so groggy that I doubted my ability to form coherent sentences.
Meanwhile, my virtuous, talented co-workers were already hours into their day. They had run several miles, skinned up the local 12,000-foot mountain, eaten nutritious breakfasts, prepared equally nutritious lunches for their children, brewed French press coffee, edited stories, and diligently prepared for this meeting, all while I was mustering the energy to press snooze on my iPhone.
Clearly, my co-workers are better people than I am—the Internet can barely catch its breath saying as much. Morning people are happier, more agreeable, more successful, more conscientious, healthier, and better at accomplishing goals. As a lifelong late sleeper, I’ve had a hard time not internalizing that my sleep behavior is somehow morally inferior. With New Year’s resolution season upon me, I’ve felt more than ever like I should do something about it.
That is, until I did some digging. Turns out that sleep patterns have less to do with virtue or motivation than I thought and a lot more to do with physiology. In fact, only three things affect whether someone is a morning person or a late sleeper: light exposure, age, and genes. In other words, much of what determines your natural sleep cycle isn’t actually in your control at all. Late risers aren’t lazy: we’re working against our physiology and genetic instructions! Maybe my overachieving co-workers need to get off their bright-eyed and bushy-tailed high horses.
But let’s back up a second. Many people think about circadian rhythms—the internal mechanism that tells your body things like when to feel sleepy and when to wake up—as a single biological clock ticking away. But it’s actually a lot more complex than that. Each cell in each organ and tissue in our body has its own peripheral ticker that produces biological rhythms. These rhythms regulate our hormone release, organ functions, and even the most basic cellular process of converting food to energy. In other words, your circadian clock is really a symphony of billions of moving parts that allow our bodies to work effectively.
How do these rhythms stay in sync with the outside environment and its 24-hour day-night cycle? “The brain is the master clock,” says Kristin Eckel-Mahan, who researches the circadian clock and metabolic health at the University of Texas Center for Metabolic and Degenerative Diseases. “It responds directly to light and synchronizes the peripheral clocks in your liver or kidney or wherever else.” This happens via the retina, which sends signals to a small area in our brains called the suprachiasmatic nucleus (SCN). Even in complete darkness, the SCN will coordinate our body’s many rhythms and physiological processes to be in harmony with each other. But when all goes according to plan, the SCN uses light data from the retina to coordinate our body’s many rhythms and physiological processes to be in harmony with each other and with the earth’s rotation. As a result, our bodies start to predict environmental cues like sunrise and sunset and our circadian rhythms adapt to them.
How our bodies respond to those cues, however, varies for each person. Scientists have a word for being an early or late riser: chronotype. A person with an early chronotype might begin their daytime physiological processes as soon as light hits them in the morning, or even before. But another person with a later chronotype might not wake up for another hour, despite being hit by the same morning sun. This difference is affected in part by age: as infants and small children, we tend to have earlier chronotypes. When we hit puberty, they get much later. During adulthood, our chronotypes swing back in the other direction, getting earlier and earlier as we age. Researchers have also found that our chronotype is determined by our genetics. This means that being a late sleeper or an earlier riser is, at least in part, something we inherit.
So what does this all mean? Basically that we are all unique snowflakes when it comes to our circadian rhythms—everyone is slightly different, no one clock necessarily better than the other. And that’s important to pay attention to. “Maintaining circadian health is a driver for all health,” says Emily Manoogian, a postdoctoral researcher who studies human circadian biology at the Salk Institute for Biological Research in Southern California. “We try to pay attention to what we are eating, what kind of exercise we are doing, and how much we are sleeping. The timing of that behavior is another aspect of being healthy.“ (There are several tests you can take to help determine your chronotype.)
The problem is that modern society too often prevents us from living in sync with our circadian clocks—we override them by not going to bed or waking up when our bodies tell us to. A large body of research has discovered a lot about how exactly this disruption can affect our physical health and even athletic performance. For example, social jet lag, or having out-of-sync circadian rhythms, has been correlated to metabolic disease and cardiovascular risk, according to a 2008 study published in the Proceedings of the National Academy of Sciences, as well as addiction and mental illness, per a 2016 Current Biology review of circadian health studies. An out-of-sync biological clock can also increase inflammation and heighten risk of injury during physical activity, says Manoogian, and according to research published last year in the Journal of Biological Rhythms, slow bone and cartilage repair.
When circadian rhythms are in sync and “everything is in phase, your gut, muscles, heart, lungs, and bones will all work better,” says Manoogian. “When you optimize your rhythms, you feel rested longer, and your whole body functions better.”
This all came as a revelation to me. My gift for ignoring my alarm clock was not only perfectly virtuous but also improving my health. “You should respect your internal clock and, ideally, allow it to work on its own time,” Manoogian says. Feeling empowered, I promptly canceled my morning running plans for the month. (As if I was going to wake up for them anyway.) Instead, I brought my shoes to work for lunchtime jogs and signed up for an evening yoga class. And I decided I was done sacrificing sleep to fit in breakfast—I stocked the office kitchen with yogurt and bagels to eat after the daily morning meeting. I also started showering and laying my clothes out in the evening—each minute of morning sleep is precious, after all. Finally, without a smidge of guilt, I changed my alarm clock an hour later to 8:30.
I felt like a new man.
Manoogian, however, would not let me forget one other important aspect of circadian health. “The same way you should let yourself sleep in, you should let yourself go to sleep,” she says. In other words, forcing yourself to stay up after you’re tired and then letting yourself sleep late is not doing you any favors. In fact, Manoogian guesses many of us are running on later clocks because of behavior, not physiology. “We force our bodies to do what what we want them to do,” she says. “And forcing your body to stay awake is just as bad as forcing it to wake up early.”
Keeping this in mind, I also started turning off my phone a few hours before bed and avoided eating after dinner (to moderate success). The latter is especially important, Eckel-Mahan told me: late-night snacks communicate to your digestive system, and thus the rest of your body, that it’s time to wake up. My extra hour of sleep in the morning was great, but making these changes in the evening and getting lots of natural light during my midday jogs (which, according to Eckel-Mahan, more powerfully signals the day-light cycle to my body) were also important. When I had all of these things going, I still had to press the snooze button once or twice in the morning, but I felt more awake and clearheaded coming into work.
Even if I’m not perfect at it, accepting my late chronotype and trying to work with it—whether allowing myself that extra hour of sleep in the morning or sneaking out for a lunch run—has improved my well-being. And if nothing else, when I roll into the morning meeting, I can rest assured that my perky, early rising co-workers are not better people than I am.