Dry January Can Reshape Sleep Patterns in the New Year

The idea behind Dry January — besides proving that you can abstain from alcohol for an entire month — is actually to set a pattern that curbs drinking for the whole year. But even in the short-term, abstaining from alcohol has some big benefits, especially when it comes to sleep.

In research released last week, Richard de Visser, Ph.D., a psychologist at the University of Sussex, found that 71 percent of his participants in a series of online surveys reported sleeping better when they abstained from alcohol for a month. This is just a survey, so it’s hard to know exactly why people reported better sleep quality, but there’s a small mountain of studies that investigate exactly what parts of the sleep cycle are affected by alcohol, and why it might make you feel exhausted — if not anxious — the next day.

Several papers dating, from as early as the Seventies, describe the relationship between certain types of sleep and alcohol as a “rebound effect.” Alcohol consumption, especially before bed, tends to upset the balance between REM (rapid eye movement sleep, the period in which dreams occur) and NREM sleep or “slow wave sleep.” In general, REM sleep and NREM sleep follow somewhat predictable 90-minute cycles. Drinking in the evenings before bedtime throws a wrench into that pattern.

To begin with, these studies found that drinking alcohol right before bedtime suppresses REM sleep at the beginning of the night in favor of slow wave sleep. For some, that makes it easier to fall asleep — though this effect is largely dose-dependent, as higher doses of alcohol increase wakefulness in this period too. But often, that period of sleep is relatively restful (that sweet, post-binge pass out). However, this tends to delay that first round REM sleep, pushing it later into the night.

In the second half of the night, these studies indicate that REM sleep returns with a vengeance. Once the body metabolizes the alcohol, REM sleep tends to occur more frequently. Still, even this overcompensation isn’t enough to repair the damage done at the beginning of the sleep cycle. The overall effect of the REM rebound is actually a more disrupted sleep pattern for those later hours, which Chris Idzikowski, Ph.D., the director of the Edinburgh Sleep center, added in response to a 2013 review that emphasized the toll that alcohol takes on REM sleep.

“One consequence of a delayed onset of the first REM sleep would be less restful sleep,” Idzikowski said in 2013. “The first REM episode is often delayed in stressful environments.”

Even if you don’t consider New Year’s eve a stressful environment, it’s a solid bet that most sleep cycles around the country are about to get pretty messed up. If Dry January doesn’t sound appealing now, it might sound better tomorrow morning.