Coffee can get you going in the morning — in more ways than one. This beverage, hot or cold, can wake up both your senses and your bowels. But why?

Samantha Oldenburg, nurse practitioner at Aurora Medical Center in Oshkosh, WI, explains what research has discovered.

You know about how caffeine makes you feel more awake. Caffeine also can energize your digestive tract, causing your colon and intestinal muscles to contract and quickly push the contents through your colon.

But decaf java makes you poop too, so caffeine isn’t the only culprit. Certain compounds in coffee, particularly chlorogenic acids and N-alkanoyl-5-hydroxytryptamides, have researchers interested in finding out more about their role in stimulating the digestive tract.

Coffee is also thought to raise levels of the hormone known as gastrin, Oldenburg explains. Similar to caffeine, gastrin can activate the colon and give you the urge to go.

Then there’s a few, simpler reasons why coffee can make you poop. The basic act of drinking or eating anything can rev up the colon and send you running to the bathroom.

It can be timing and your internal clock.

“Your colon is twice as active after waking up than it is while you’re sleeping,” Oldenburg says. “Many of your physiological processes are in a natural rhythm and your body is simply telling you it’s time to go.”

And what you put in your morning cup of coffee could have an effect, too. For those who are lactose sensitive or intolerant, adding milk or cream can trigger digestive issues like bloating, cramping and diarrhea soon after drinking.

Bottom line? Although coffee doesn’t make everyone poop, if you’re not regular, a cup of joe just might do the trick.