If you've ever felt like mosquitoes prefer you more than your friend, it's not all in your head. As this video from The Science of Us explains, some of us are extra appealing to the little pests. They're not exactly drawn to "sweet blood"—though they are more attracted to type O—but rather people who give off more carbon dioxide: people who are larger, have just worked out, or are hyperactive. Even if that doesn't describe you, it's probably a good idea to wear bug spray this summer.

READ THIS NEXT: These 8 Bug Sprays Are Useless Against Zika 34U34 Mental Health Promo