To paraphrase the old beer adage, you never buy a cup of coffee – you only rent it. As you wait in line for the bathroom at your favorite coffee shop, you may be wondering why this particular bevvie has such a powerful effect on your bladder.

Find out what the experts have to say about this journey, from the first delicious sip to the mad dash to pee, and every stop in between.

Everything you swallow goes straight into your stomach. Depending on how much is already there – whether it’s your first sip of the day or you’ve just eaten a large meal – it can stay in the stomach from five minutes to over an hour.

Liquids are quicker to digest than solid foods, so your body immediately gets to work with a cup of coffee on an empty stomach, sending it through your intestines, kidneys and out to your bladder. And that’s where caffeinated coffee is different from some other drinks, according to Lisa Andersonassociate professor of integrative biology and physiology at the University of Minnesota.

“The small intestine uses osmosis to absorb fluid, using energy to suck up sodium and other electrolytes so that the fluid follows these particles,” Anderson told HuffPost. “With caffeinated coffee, the caffeine, polyphenols and other coffee molecules are all fat-soluble, meaning they easily pass through the lining of the gastrointestinal tract.”

We’ve finally arrived at the moment of truth, where it’s time to talk about your new word of the day, “urination,” which Anderson says is a scientific word for pee.

“Once the fluid hits the bladder, the sensors start to notice that the bladder is filling,” Anderson said. “This triggers signals to the urination center (you see, that’s it) in your brainstem, which sits alongside other centers that tell you things like when you’re thirsty, hungry, or need to vomit.

Coffee speeds up the process because the caffeine it contains provides additional stimulation to the detrusor muscle, a smooth muscle in the bladder wall. (It stays relaxed so the bladder can store urine, and it contracts when it’s time.) As your brain and bladder work together, you suddenly ask the person sitting next to you in the cafe, ” Would you like to look at my stuff? for a minute while I go to the bathroom?

This accelerated process is even faster if you have an overactive bladder, Anderson said, citing studies of people with the disorder. Drinking eight ounces of caffeinated water made them go to the bathroom much sooner than when they drank just eight ounces of plain water.

Another fun fact about your bladder size: That short line to the men’s room isn’t just about the patriarchy. It turns out that men “can hold more fluid in their bladder and hold it in longer,” Anderson said.

While everything you drink eventually needs to be eliminated, it’s the caffeine in coffee that, uh, speeds up the process. “Caffeine is an irritant to the bladder, and when the bladder is irritated, it begins to contract. » said Dr. Rena Malik, urologist and assistant professor of surgery and director of female pelvic medicine and reconstructive surgery at the University of Maryland School of Medicine. “This contraction is what gives you that feeling of what we urologists call ‘urgency,’ which is the sudden desire to go to the bathroom that you can’t delay.”

Malik noted that studies have shown that although caffeine increases urgency, those who consume a lot of it – in the form of drinks or food – may develop some resistance. In her practice, she sees great variety in everyone’s body. “Some patients tell me that drinking even a single cup of coffee makes their morning miserable, and others can drink a lot without suffering any ill effects.”

Although coffee is a liquid, caffeine is a diuretic, meaning your kidneys can extract more fluid from your system than you just consumed, without hydrating you at all. So if you feel like you’re peeing more than you just drank, you might be absolutely right. And you need to put pure water in your system, stat.

The more caffeine you drink, the worse it can get. “The diuretic properties of caffeine manifest at higher levels of consumption,” Anderson said. “You typically need to ingest more than 400 mg of caffeine for it to have a significant impact on your body’s fluid balance.” This is approximately the amount of caffeine in four cups of brewed coffee, which is also the recommended limit for daily consumption.

Malik said a quick way to tell if you’re dehydrated from all that coffee is to check the color of your urine. “If it’s really dark yellow, you need more fluids in your system,” she said. “If it’s almost clear, you’re drinking too much.” But if your urine is lemonade yellow, your fluid levels are probably well balanced.

If you want to reduce the frequency of your bathroom breaks, you don’t have to indulge in caffeine, Malik said. “There’s nothing wrong with taking it slowly, so if, for example, you drink two cups of coffee every morning, try having one regular and one decaffeinated and see what happens.”

Finally, if you feel like you’re spending most of your life in a toilet, Malik urges you to see a urologist. “People might think, ‘This is how I’ve been my whole life,’ but there’s no need to suffer. A urologist can help you review all of your options, including lifestyle changes, medications, and procedures.