Summarize this article in one sentence.
It is always best to know your adversary before going into battle, right? Chiles are perceived as hot or spicy to us because they contain the chemical capsaicin, which enters your bloodstream and essentially convinces your body that your temperature is rising. This helps explain the sweating, flushing, and occasional light-headedness that can accompany eating spicy foods. Carried in oils in chiles, capsaicin is also a skin and mucous membrane irritant. Capsaicin is a natural defense mechanism developed by certain plants to prevent mammals from eating them. Most mammals take the hint and move on, but not us. Are humans just not as smart as mice, pigs, and other mammals? It probably has more to do with our brain makeup. Our brain neurons responsible for pleasure and pain are adjacent and possibly interconnected. This helps explain why many people get a rush out of risky behavior, especially when they can experience danger/pain without much risk, such as in eating spicy food. People tend to assume that spicy foods cause ulcers, heartburn, and other gastrointestinal discomforts, but in fact there is no real evidence to support this. If they have this effect on you, it is likely just a sensitivity you have, like others may have to dairy, fatty foods, etc. Indeed, there is growing scientific evidence that spicy foods are good for you: they may help you consume less calories by reducing sweet/salty/fatty cravings; increase calorie burning by increasing your body's perceived core temperature; have beneficial impacts on cardiovascular health and cholesterol levels; and, surprisingly enough, reduce gastric acid production. Pepper spray does indeed contain capsaicin, the same thing in those chiles you want to add to your dinner plate. So don't treat them lightly, unless you want a taste of what it is like to be pepper sprayed. Use gloves when preparing chiles. Or, at very least, wash your hands thoroughly after handling them. Protect your eyes and other sensitive areas. Consider eyewear when cutting chiles. Do not rub your eyes, nose, or mouth before washing your hands. For that matter, if you need to use the bathroom or have an itch in a sensitive area, make sure you wash your hands before (and after!). The hottest parts of a chile are the seeds and the inner membranes (usually white) that hold them in place. This is where most of the capsaicin is located. Scrape these away while preparing a chile if you want to tone things down.

Summary:
Know about capsaicin. Think about why people subject themselves to spicy foods. Understand the health impacts of spicy food. Learn to prepare chiles carefully.