It turns out caffeine is probably the culprit.

By Tim Nelson
May 11, 2021
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For millions of us, coffee plays a vital role in the morning routine. Not only does its allure coax us out of bed, it gets us up and moving — probably to the bathroom

It might be a bit crude to discuss on a food website, but let's not pretend like coffee doesn't come out as pee pretty quickly after your morning cup. Though it might seem like there's something uniquely bizarre going with your body, a recent HuffPost story explains that there's a whole lot of perfectly normal biological processes that inform the coffee-commode connection. 

Part of the reason coffee moves out of the body so quickly is that we digest liquids faster than solid food. Especially if you're drinking coffee on an empty stomach right after waking up, there isn't too much else for your digestive system to handle, providing a clear route through the intestines and kidneys on the way to the bladder. 

Assuming your coffee contains caffeine, that already-fast process will work even faster. "The small intestine uses osmosis to absorb the liquid, using energy to pull in sodium and other electrolytes so the liquid follows those particles," Lisa Anderson, associate professor of integrative biology and physiology at the University of Minnesota, told HuffPost. "With caffeinated coffee, the caffeine, polyphenols and other coffee molecules are all lipid-soluble, which means they pass easily across the lining of the gastrointestinal tract."

Caffeine isn't done wreaking its havoc once that liquid gets to your bladder, either. As the bladder fills up and starts sending signals to the "micturition center" (a fancy word for the part of the brain that tells you it's time to pee), caffeine stimulates the bladder wall's detrusor muscle, which will get your attention, so to speak. 

"Caffeine is a bladder irritant, and when the bladder is irritated, it starts to contract," Dr. Rena Malik, a urologist and assistant professor of surgery and director of female pelvic medicine and reconstructive surgery at the University of Maryland School of Medicine, told HuffPo. "That contraction is what gives you that sense of what we urologists call 'urgency,' which is the sudden desire to go to the bathroom that you can't delay."

Milk Drip Into Coffee On Wood Board
Credit: 1_nude via Getty Images

Not only will caffeinated coffee exaggerate that sense of urgency, but the volume as well. Because caffeine is a diuretic, that coffee actually pulls fluid out of your kidneys in addition to whatever liquid was in your morning cup. So if your morning micturition involves a greater amount of fluid than you're sure you just drank, there's nothing to be alarmed about — so long as you're not drinking more than 400 milligrams of caffeine in a short span of time. Either way, it doesn't hurt to follow up that coffee with some water just to make sure things are balanced out. 

So is that more than you ever wanted to know about coffee and pee? Maybe. If you're really concerned about how often one is leading to the other, it might not hurt to switch to decaf, or talk to a urologist if you think it's a serious problem. If you're more curious than alarmed, just know that bathroom break is a small price to pay for those precious sips of caffeinated bean water. 

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