How does alcohol cause hangovers? - Judy Grisel
In a 1973 study, 20 volunteers got drunk
once a week for 8 consecutive weeks,
each time on a different
alcoholic beverage,
and each time with precisely
the same dosage—
this was science,
after all.
The goal of this experiment was to find
out which alcoholic drinks
cause worse hangovers.
Of course, it takes much more than one
small study to answer such a question.
Since then, science has
learned a lot about hangovers—
though some mysteries remain.
The molecule responsible
for hangovers is ethanol,
which we colloquially refer to as alcohol.
Ethanol is present in all alcoholic
beverages, and generally speaking,
the more ethanol,
the greater the potential for a hangover.
The symptoms and severity can vary
depending on weight, age,
genetics, and other factors.
But still, hangovers generally share
some common— and unpleasant— features.
So how exactly does alcohol
cause a hangover?
And is there any way
to reliably prevent one?
Alcohol slows down the communication
between neural cells.
After someone has had their last drink,
as the concentration of alcohol
in the blood drops back to zero,
the brain rebounds from sedation
and swings in the other direction,
entering a hyperactive state.
This may lead to the tremors or
rapid heartbeat associated with hangovers.
It also makes sleep shorter
and less restful than normal.
But these effects are just the beginning—
alcohol impacts so many
of the body’s processes,
throwing delicate balances off-kilter.
And even the most familiar hangover
symptoms have surprising contributors.
For example, alcohol disrupts
levels of many hormones.
One of those hormones is cortisol.
Normally, fluctuating cortisol levels
help regulate wakefulness
throughout the day and night.
So the disruption in cortisol
during a hangover
may cause people to feel groggy
or disoriented.
Another hormone alcohol interferes
with is vasopressin,
which normally decreases the volume
of urine made by the kidneys.
By decreasing levels of vasopressin,
alcohol causes people to pee more
and become dehydrated.
Dehydration can lead to thirst, dry mouth,
weakness, lightheadedness, and headache,
one of the most common hangover symptoms.
In addition to dehydration,
hangover headaches can result
from alcohol’s influence
on chemical signaling in the brain,
especially on neurotransmitters
involved in pain signaling.
Alcohol can also damage mitochondria,
which are responsible for producing
the ATP that gives us energy.
This may contribute to the fatigue,
weakness, and mood disturbances
experienced during a hangover.
Meanwhile, alcohol stimulates
the immune system,
leading to inflammation that can
damage cells within the brain,
affect mood, and impair memory.
And it can irritate
the gastrointestinal tract
and inflame the lining
of the stomach and intestines.
Alcohol may also slow down
stomach emptying,
which could lead to increased
production of gastric acid.
This is why alcohol can cause
stomach pain, nausea, and vomiting.
Alcoholic drinks also contain other
substances that are produced
during the fermentation process
that give the drink its specific flavor.
Some evidence suggests that one of these,
methanol,
is particularly bad for hangovers.
The body doesn’t start
metabolizing methanol
until it’s done processing ethanol.
And when it does,
the toxic metabolites of methanol
may potentially worsen
the hangover symptoms.
Beverages that are closer to pure ethanol,
such as gin and vodka,
may cause fewer hangover effects.
Meanwhile, the presence of flavoring
ingredients in beverages
like whiskey, brandy, and red wine,
may make these kinds of alcohol
cause more hangover symptoms.
So, the choice of alcoholic
beverage matters,
but any of them can cause hangovers,
simply because they all contain alcohol.
So, do common hangover remedies
actually work?
Drinking water and electrolyte beverages
can help reduce symptoms
related to dehydration.
And eating— especially carbs—
can help replenish the glucose levels
alcohol reduces.
But ultimately, the only sure way
to prevent a hangover
is to drink alcohol in moderation
or not at all.
