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Experts say drinking coffee at night probably won’t affect your sleep pattern that much. Getty Images
  • Researchers say nicotine and alcohol before bedtime can have a negative impact on the quantity and quality of sleep.
  • Experts say coffee and other caffeinated beverages don’t significantly affect sleep patterns for most people.
  • Doctors are being urged to tell people with sleep difficulties to avoid smoking or drinking alcohol in the hours before they go to sleep

We could all use more sleep — or at least better quality sleep.

And people who smoke cigarettes or have an evening drink may be cheating themselves out of some important deep slumber.

New research published in the journal Sleep suggests that to get a good night’s rest, you should cut back on nicotine and alcohol, and not necessarily caffeine, four hours before bed.

They say that could help improve the quality and quantity of your sleep.

A study led by a researcher at Florida Atlantic University (FAU) — with help from Brigham and Women’s Hospital, Harvard University, Emory University, the University of Mississippi Medical Center, and the National Institutes of Health — focused on the evening consumption of alcohol, caffeine, and nicotine among 785 African-Americans over a combined 5,164 days.

Researchers measured their corresponding sleep using wristwatch-like sensors and participants’ daily entries into sleep diaries.

Researchers say their data showed that people who used nicotine and alcohol within four hours of going to bed felt the largest impact on their sleep cycle, even when controlling for age, gender, stress, and other factors.

Nicotine was particularly harsh on people with insomnia. Using nicotine at night resulted in a more than 40-minute reduction in overall sleep.

The study authors note that because nicotine was the most commonly used substance that kept people up at night, it was yet another reason for people to quit this unhealthy habit. That includes smoking, vaping, dipping, and all the other ways nicotine can be ingested.

One important detail of the study is that it focused on African Americans who didn’t think they had problems sleeping at night and followed them through different points in their daily routines, from waking up for school to waking up for work.

“African Americans have been underrepresented in studies examining the associations of nicotine, alcohol, and caffeine use on sleep,” Christine E. Spadola, PhD, lead author of the study and an assistant professor in FAU’s Phyllis and Harvey Sandler School of Social Work, said in a press release. “This is especially significant because African Americans are more likely to experience short sleep duration and fragmented sleep compared to non-Hispanic whites as well as more deleterious health consequences associated with inadequate sleep than other racial or ethnic groups.”

The study authors also note their findings support recommending that doctors and others in the healthcare field to advise people who complain about sleep difficulties to limit nicotine and alcohol consumption before bedtime.

The researchers, however, found little correlation between coffee consumption within four hours of going to bed and sleep difficulties.

Researchers did warn that dosing, sensitivity, and tolerance weren’t measured and “can play an important role in the association between caffeine use and sleep.”

Basically, the study suggests that it’s that late-night smoke or vape and the extra glass of wine after dinner that are keeping you up, not necessarily that 4 p.m. cup of coffee to get you through those last hours of work.

Rose MacDowell, chief research officer at Sleepopolis, says while caffeine gets the majority of the press as a sleep-interrupting substance, nicotine and alcohol can have a powerful negative impact on sleep.

“In fact, heavy use of alcohol can permanently damage the genes involved in healthy sleep and wake cycles,” she told Healthline.

But MacDowell also says a person’s sleep may be disrupted as nicotine levels drop toward the morning hours, which would increase a person’s cravings.

“A brain in withdrawal from nicotine may wake you up to satisfy its craving,” she said. “Because of its effect on the lungs and blood vessels, nicotine can increase breathing disorders that impact sleep, such as asthma and sleep apnea. Vaping may not involve the inhalation of smoke, but may deliver more powerful stimulant effects than smoked nicotine, disrupting sleep even further.”

Martin Reed, a certified clinical sleep health educator and founder of Insomnia Coach, says the best way to prohibit nicotine, alcohol, or caffeine from interrupting your sleep is to avoid those substances close to bedtime.

“As confirmed in this research, caffeine actually has less of an effect on our sleep than many people worry about,” Reed told Healthline. “As long as you don’t drink pitchers and pitchers of coffee just before bed, caffeine is unlikely to have a major negative impact on sleep.”

Because nicotine is also a stimulant, Reed says consuming it before bed is going to make sleep more difficult, as it can mask typical signs of sleepiness.

“If we wake during the night and consume nicotine — perhaps in an attempt to help us relax — we can actually make it more difficult to fall back to sleep,” he said. “I suggest trying to avoid smoking at least two hours before you plan on going to bed and to avoid smoking if you wake during the night.”

Then there’s alcohol.

While it can help people fall asleep, the process of breaking it down has a stimulant effect. That means a few nightcaps might help you close your eyes faster, but they may ultimately oust you from your roost before you’re ready.

“Limiting alcohol consumption to one or two glasses of wine or beer with dinner, three to four hours before bedtime will help minimize any sleep disruption,” Reed said.