Snoring is harmless. Five hours of sleep is enough. Alcohol before bed helps. These are all sleep myths debunked as false in a peer-reviewed study published Tuesday in National Sleep Foundation's journal Sleep Health.

After reviewing more than 8,000 websites, researchers at New York University School of Medicine identified 20 sleep myths and debunked them using a "falseness" scale and a panel of sleep experts.

"Sleep is a vital part of life that affects our productivity, mood, and general health and well-being," said Rebecca Robbins, lead investigator and postdoctoral research fellow at NYU Langone Health, in a statement. "Dispelling myths about sleep promotes healthier sleep habits which, in turn, promote overall better health."

Myths spanned sleep duration, sleep timing, behaviors during sleep, daytime behaviors related to sleep, pre-sleep behaviors and brain function and sleep.

They included “during sleep the brain is not active," “sleeping in during the weekends is a good way to ensure you get adequate sleep" and “many adults need only five or less hours of sleep for general health.”

Snoring, while cited as annoying for bed partners, also was viewed as "mostly harmless," in searches. Researchers cited that snoring is a primary symptom of obstructive sleep apnea and could place individuals at high risk for cardiovascular problems.

Napping in the afternoon also was debunked as unhealthy, when it is habitual. Researchers say this is because napping can enable nighttime insomnia.

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Alcohol shouldn't be viewed as a sleeping aide, as researchers said it often causes sleep disturbances in the second half of the night and can negatively impact REM sleep.

The idea that hitting the snooze button could be better than waking up when the alarm first goes off also was deemed false. Fragmenting sleep like this can decrease "mental flexibility" and negatively affect mood, according to the study.

Watching TV before bed, exercising within four hours of bedtime and keeping a warmer bedroom for better sleep also were found to be false.

Some myths did cause disagreement between experts, and study authors suggest more research should be done.

A third of U.S. adults say they do not get the recommended amount of sleep each night, according to the Centers for Disease Control and Prevention. For adults, that's at least seven hours a night.

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