CHARLOTTE, N.C. – Sleep and alcohol consumption in young adults seems to follow a “vicious cycle,” as one observer called it.and those who went to bed earlier and slept longer tended to drink less the next day, a study of drinking and sleeping habits in 21- to 29-year-olds found.
“Sleep is a potential factor that we could intervene on to really identify how to improve drinking behaviors among young adults,” David Reichenberger, a graduate student at Penn State University, University Park, said in an interview after he presented his findings at the annual meeting of the Associated Professional Sleep Societies.
This is one of the few studies of alcohol consumption and sleep patterns that used an objective measure of alcohol consumption, Mr. Reichenberger said. The study evaluated sleep and alcohol consumption patterns in 222 regularly drinking young adults over 6 consecutive days. Study participants completed morning smartphone-based questionnaires, reporting their previous night’s bedtime, sleep duration, sleep quality, and number of drinks consumed. They also wore an alcohol monitor that continuously measured their transdermal alcohol consumption (TAC).
The study analyzed the data using two sets of multilevel models: A linear model that looked at how each drinking predictor was associated with each sleep variable and a Poisson model to determine how sleep predicted next-day alcohol use.
“We found that higher average peak TAC – that is, how intoxicated they got – was associated with a 19-minute later bedtime among young adults,” Mr. Reichenberger said. “Later bedtimes were then associated with a 26% greater TAC among those adults” (P < .02).
Patterns of alcohol consumption and sleep
On days when participants recorded a higher peak TAC, bedtime was delayed, sleep duration was shorter, and subjective sleep quality was worse, he said. However, none of the sleep variables predicted next-day peak TAC.
“We found an association between the duration of the drinking episode and later bedtimes among young adults,” he added. “And on days when the drinking episodes were longer, subsequent sleep was delayed and sleep quality was worse. But we also found that after nights when they had a later bedtime, next-day drinking episodes were about 7% longer.”
Conversely, young adults who had earlier bedtimes and longer sleep durations tended to consume fewer drinks and they achieved lower intoxication levels the next day, Mr. Reichenberger said.
Between-person results showed that young adults who tended to go to bed later drank on average 24% more the next day (P < .01). Also, each extra hour of sleep was associated with a 14% decrease in drinking the next day (P < .03).
Participants who drank more went to bed on average 12-19 minutes later (P < .01) and slept 5 fewer minutes (P < .01). Within-person results showed that on nights when participants drank more than usual they went to bed 8-13 minutes later (P < .01), slept 2-4 fewer minutes (P < .03), and had worse sleep quality (P < .01).
Mr. Reichenberger acknowledged one limitation of the study: Measuring sleep and alcohol consumption patterns over 6 days might not be long enough. Future studies should address that.