The idea of a nightcap – a drink before bed – is a popular one. Many people believe that a drink or two before you turn out the lights helps you sleep better. While research has proven that this is not the case, for people with sleep apnea, a drink before bed can actually be dangerous. Alcohol and sleep apnea don’t mix. Here are eight risks.

Alcohol and sleep apnea: A bad mix

An estimated 25 million people in the U.S. suffer from one of three forms of sleep apnea. These include:

  1. Obstructive sleep apnea: The most common form. The muscles of the throat and tongue relax during sleep, obstructing the sleeper’s airway.
  2. Central sleep apnea: The reflexive part of the central nervous system essentially forgets to tell the body to breath. This is a rare form of sleep apnea.
  3. Complex sleep apnea: Thankfully the most rare of the three forms, complex sleep apnea is a dangerous combination of the first two forms.

During the night, those with sleep apnea will stop breathing as many as 20 times an hour, all night long. The brain realizes what is happening and sends the signal to breathe, with the sleeper taking a gasping intake of breath without waking fully. Daytime fatigue, migraines, and mental fogginess are some of the main symptoms of sleep apnea.

What occurs during sleep?

To understand how alcohol and sleep apnea are connected, it’s important to understand sleep itself. Sleep has two main stages, with a small transitional period between them: slow wave and rapid eye movement types of sleep. Slow wave sleep is the deep, restorative state of sleep that makes up 75% of your nightly sleep. During this time, your brain waves slow down and relax.

In contrast, rapid eye movement (REM) sleep is light and often characterized by movement in the eyes. The body seems to require this type of sleep as well in order to be fully rested.

How can alcohol affect sleep?

During sleep, the brain produces serotonin and epinephrine. The former brings sleep on and the latter regulates the REM stages of sleep. Alcohol disrupts the production of these two chemicals, changing the patterns of sleep even after just one drink so that sleep is uneven, irregular, and often interrupted.

Additionally, alcohol decreases the body’s arousal response. This response is a reflex that tells the brain you aren’t breathing or that something is wrong, waking you.

Finally, sleepers may also experience more apneas (pauses in breathing) that result in lower oxygen levels in the blood after drinking. These drops, called desaturations, come with an increase of carbon dioxide in the blood (normally exhaled from the body). The lack of carbon dioxide exchange can literally poison sleepers.

People with sleep apnea already have increased risks when it comes to severe health complications, but alcohol increases these risks and makes them more likely to occur.

Alcohol effects on sleep apnea

Alcohol’s effects on sleep apnea are well-documented. Here are eight primary effects of alcohol on sleep apnea.

1. Alcohol can increase BMI, which increases risk of sleep apnea

Studies have found that obesity is a major risk factor for developing sleep apnea (or worsening already-present sleep disordered breathing).

2. Alcohol increases the risk of sleep disordered breathing

Lead investigator Paul Peppard, PhD, senior epidemiologist with the Population Health Institute, University of Wisconsin Medical School, Madison and his team:

“…found that in men, even moderate habitual alcohol consumption increased the risk of sleep-disordered breathing. Each additional alcohol drink per day increased the odds of sleep-disordered breathing by approximately 25%.”

3. Alcohol changes the way your airways work

The consumption of alcohol relaxes your upper airway, making it vulnerable to collapse, while simultaneously increasing nasal resistance.

Increased nasal resistance is associated with