Imagine that you normally eat lunch at noon everyday. But today — surprise! — your boss calls a quick meeting at right at noon. You think, It’s okay, it’s no big deal, I’ll just eat right after.But as fifteen minutes pass, and then 20, and then 30, that “quick meeting” is starting to feel like a grueling marathon. By 1:00pm, your dull hunger pangs have become an angry hunger roar.

“You are starving, right?” says says Michael Grandner, PhD, MTR, a Fitbit sleep advisor and director of the Sleep and Health Research Program at the University of Arizona College of Medicine. “It’s because you trained your body when to eat and, like a faithful Labrador, our bodies are trainable.”

Creatures of Habit

While a lot of us eat lunch around the same time everyday, the same can’t be said for the time we hit the sack. We stay up late on weekends, knowing that we won’t need to wake up for work, but then don’t feel tired when Sunday night rolls around—so we don’t get enough sleep for Monday morning, which throws our sleep schedule off-kilter for the rest of the week.

According to the National Sleep Foundation’s 2014 Sleep Index, 35 percent of adults say their sleep quality is only “fair” or downright “poor.” And a more recent poll conducted by the Robert Wood Johnson Foundation shows one out of three adults don’t get enough sleep—less than seven hours per night, which has been linked to several chronic health condition, including heart disease, kidney disease, and high blood pressure, as well as mental health issues such as  depression and anxiety.

Getting to bed at a consistent hour every single night can help. “The body loves regularity,” says Grandner. “We are creatures of habit.” Just like our body prepares itself and relies on food at the same times each day, the body does the same for sleep. “When we have a regular bedtime, our sleep biology can rally around that and train itself around that time,” Grandner explains. “If you keep it regular enough, your body knows when it is coming, so it can optimally prepare.”

How a Regular Bedtime Aids the Body

A lot happens during sleep. Your body is recharging its energy stores. Growth hormone is released, repairing and building tissue and muscle. Levels of cortisol (a.k.a. the stress hormone) fall during the night, so they can rise to a reasonable level in the morning and keep us alert. Immune function is bolstered, and levels of ghrelin and leptin are regulated to keep our feelings of hunger and fullness in check.

So, although we spend about a third of our life under the veil of sleep, it’s far from lost time. “Sleep is critical for many body functions and keeps many systems in balance,” says Grandner. “And your body has a much easier time doing that if it has a regular, predictable bedtime.”

If you get a regular bedtime, Grandner says you may begin to notice body benefits throughout the day (and beyond). You may notice you have better energy and more focus. You may notice that you get sick less often. You may make better dietary choices, and find that you are able to exercise more often and at higher intensities, because regular sleep “supports these metabolic and physical systems,” says Grandner.

How to Get Consistent

Like that friend who always shows up on your doorstep instead of calling ahead, your body prefers to know when sleep is coming—which means having a bedtime in place. “Otherwise, your body doesn’t really know when sleep is coming, so it can’t prepare,” Grandner says. “As a result, it has a harder time keeping all those systems in balance.

To keep a more consistent bedtime, Grandner says to “make sure that you give yourself enough time.” You know the hour you want to hit the sack, so think ahead. Get into your PJs and brush your teeth early, so you don’t wake yourself up in the process of preparing for bed. Power down your technology and gadgets at least 30 minutes before bedtime, since the emitted blue light can keep you awake.

Once you climb between the sheets, have some quiet time. Read a magazine or book (not an e-reader) with a small nightstand light, if you’re still not totally ready for Zzzz. Pretty soon, you’ll be a creature of beneficial bedtime habits.