Exercise and Metabolism

(© Imaginechina/Corbis)
In addition to carbon dioxide, mosquitoes find victims at closer range by smelling the lactic acid, uric acid, ammonia and other substances expelled via their sweat, and are also attracted to people with higher body temperatures. Because strenuous exercise increases the buildup of lactic acid and heat in your body, it likely makes you stand out to the insects. Meanwhile, genetic factors influence the amount of uric acid and other substances naturally emitted by each person, making some people more easily found by mosquitos than others.