If you’ve ever sat in front of a plate of wings with tears streaming, sweat dripping, or snot running, you’ve probably wondered how to up your spice tolerance. While some people find themselves in a world of hurt from freshly grated black pepper on their pasta, others dive into threateningly red bowls of pozole with the enthusiasm of Guy Fieri at a cheesy-fry buffet.

More than 20 years ago, salsa crept passed ketchup in the U.S. condiment sales market, and American palates began to seek adventure in earnest. A 2013 Technomic study showed that 54% of Americans prefer spicy sauces and dips—a number that was and likely still is increasing rapidly. Unlike so many other taste preferences, though, the growth of spice brings with it a prickly issue: How much heat can your tongue handle? As supermarket snacks (Flamin’ Hot Cheetos, Sriracha Popcorn) and fast food (KFC’s Nashville Hot Chicken, McDonald’s Hot N’ Spicy McChicken, Wendy’s Ghost Pepper Fries) crank up the Scoville units, consumers are left to find their breaking point—and, if they so choose, figure out how to change it.

For those that experience an adrenaline rush from eating spicy foods, the growth of intense spice availability sounds appealing. Meanwhile, others ponder why they can’t down spice-laden soups or Scotch Bonnet pepper sauce. But what’s to blame for your spice tolerance? You can work to actively change it if you’re gearing up for a trip to Sri Lanka or Seoul, but could it be that certain people are just genetically predisposed to be immune to the capsaicin that causes spice in chile peppers? Or are those that can guzzle Sriracha and smear harissa on their hot dogs just better trained than those who cringe at curry?

With the help of flavor scientists and chile-pepper historians, we take a look at how the human body handles heat. 

In a scientific study comparing the results of fraternal and identical twins’ reactions to spice-spiked foods, results showed that 18-58% of a preference comes from genetics. Essentially, the study found that identical twins (those that share the same genetic material) were that much more likely to have the same levels of reaction to spice as fraternal twins (people with shared environmental upbringing, but not genes).

Dave Dewitt—a chile-pepper historian nicknamed the "Pope of Peppers"—says your reaction to heat, and more specifically the compound capsaicin, has to do with what you've inherited. "The people born with no capsaicin receptors are those you see chugging bottles of super hot sauce. It's similar to an allergy—there are people who are not allergic to poison ivy."

While scientists generally agree that genetics play a part, not too many other studies have delved into exactly why. So you can blame your parents for at least a little bit of how you react to spicy foods. The rest, though, is personal. Within that, we found in talking to food-science nerds and professionals who spend their life studying such topics, ties to two factors: training and personality.

For those that like eating spicy food and want to dive freely into numbing bowls of Sichuan fish or slather their jerk chicken in Scotch Bonnet peppers, it’s great news that spice is trainable. But the initial preference for spicy foods may come at least as much from their personality as it does from their genes. “Chili-heads like the burn more, not just perceive it less," explained researcher Dr. John Hayes, an associate professor of food science and the director of the sensory evaluation center of Penn State, in a Popular Science article. Studies linked those who enjoy spicy food to liking thrill-seeking behaviors: roller-coasters or extreme sports. A study by Dr. Paul Rozin, professor of psychology at Penn, suggested that the pain of eating peppers becomes what he calls benign masochism: “This realization that the body has been fooled, and that there is no real danger, leads to pleasure derived from ‘mind over body.’” What it takes to get to that thrill, though, comes in part from conditioning your senses. 

Exposing children to heat at a young age, scientists have found, desensitized nerve endings. But John Prescott—author of Taste Matters: Why We Like the Foods We Do, researcher on food perceptions, and authority on all matters pertaining to flavor preference—is quick to point out that it is not the clichéd killing of taste buds: “Chiles don’t kill tastes buds. And even if they did, it wouldn’t be a worry—they only have a lifespan of 10-14 days.” But repetition does work to build up tolerance for higher spice levels.

“Heat tolerance is definitely trainable,” says J. Kenji López-Alt, the science-oriented food writer behind The Food Lab. “Kids who grow up in areas where spicy food is the norm are exposed to it from an early age and grow up eating spicy things just fine. People who don't grow up eating spicy food can learn to do it by repetition (see: my wife).” Prescott offers examples of places such as Mexico or Korea: There are numbers of people there who are quite sensitive to spice, but who still develop a sufficient liking to eat it every day.

Eating spicy food to build your tolerance works in two different ways, says Prescott. The first is temporary and reversible: desensitization. “Essentially, the pain receptors respond much less,” but that condition lasts just a few days. The second is called a context effect and is longer term. “Repeated consumption re-sets your internal guide as to what constitutes ‘hot’ or ‘very hot.’” Lopez-Alt offers his recommendations on how to work your way to a higher heat threshold: “Start slow and build up. Have some rice, bread, yogurt, or milk handy (not water).”

Prescott summarizes the basics of what we know about why people can or cannot tolerate spicy foods—and whether or not they like it: Research shows that some people are more sensitive to heat, he says, but there is no certainty about why. They could have more taste buds, or there may be other genetic differences. But, “regardless of sensitivity, we can all develop a liking for spiciness through repeated consumption.” If, of course, you're willing to withstand the heat for the rush of endorphins. 

Connoisseurs know that the sensation of eating spicy foods varies, depending on the strain of heat that's being consumed. Sometimes the "pain" will be described as a numbing of the body; other times you might feel something in your ears. Dave Dewitt says the reaction to black pepper and horseradish is different than, say, a haban​ero because of chemical make-up—specifically due to the presence of isothiocyanates in the first two examples, which can be found in other root crops. "They react upon your tongue in a different manner. It feels spicy but it's not a burning sensation—rather, it affects your nasal and sinus passages, not your tongue," says Dewitt. "That's why the burning sensation is on the upper inside part of your mouth." 

While someone like DeWitt has never experienced digestive problems from eating hot peppers, he's not willing to dismiss the conceit of "it burns coming in and going out."  "I’ve never had a problem with my bowels being inflamed from eating spicy food. When people say that [though], I accept they’re telling the truth," says DeWitt. "However, the body completely digests the chile peppers, so theoretically there should be nothing spicy left. People are so different that the reactions to these chemicals will vary enormously."