When we drink alcohol why we feel sleepy
Answers
Answer:
Explanation:
Beer, wine and other alcoholic beverages have somewhat of a split personality in how they affect people's brains. At first, the drinks tend to make people feel super sleepy, but they then jolt those same people wide awake and make them jittery just a few hours later. What's behind this odd effect?
The answer has to do with alcohol's powerful effects on the central nervous system, said A. Leslie Morrow, a professor of psychiatry and pharmacology at the University of North Carolina School of Medicine.
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Alcohol enters the bloodstream quickly, usually within about 20 minutes of a person drinking it. It's a small molecule, so once alcohol is in the bloodstream, it can easily cross the blood-brain barrier and affect brain cells, known as neurons, Morrow said. [Why DoWe Sleep?]
In the brain, alcohol targets protein molecules, including GABA-A receptors, which are present on more than 80 percent of all neurons. Normally, these receptors are the destination for GABA (gamma-aminobutyric acid), a neurotransmitter (chemical messenger). Typically, GABA binds to these receptors and opens a channel, letting chloride ions move inside of neurons.
Once chloride ions enter a neuron, they act like light-switch dimmers, slowing down that neuron's firing.
"When you reduce neuronal firing, that causes relaxation, sedation, sleepiness," Morrow told Live Science. If neuronal firing drops too much, it can cause coma and ultimately death, she said.
Alcohol enhances this effect, she explained. That's why when people drink alcohol, they feel more relaxed, more sedated and sleepier than usual. "They might have motor incoordination," Morrow added. "They might forget where they parked their car. They might not be able to concentrate on their homework."
If a person has a high alcohol tolerance, it might take a few more drinks for them to feel this way, Morrow noted. This explains why people with a low tolerance tend to feel these effects, including sleepiness, sooner than people with a higher tolerance.
Alcohol acts on GABA-A receptors to make people (except for chronic alcoholics) feel sleepier than usual after just a few drinks.