If you're introduced to someone who immediately makes your heart go gaga, it might be best to avoid a handshake. Sweating palms is a classic physiological response to attraction. The same cocktail of chemicals that prods our pulses also stokes our sweat glands. Collectively known as monoamines, dopamine, norepinephrine and serotonin combine to produce feelings of excitement, with a side of breathlessness and moist hands [source: McLoughlin]. Norepinephrine in particular is the culprit for goading our sweat glands into activation, and since our palms are riddled with up to 3,000 miniscule sweat glands per square inch, they can quickly become a telltale signal of sexual interest.
Men also might be stricken with sweaty palms more often than women. Rutgers University anthropologist Helen Fisher suggests that since men are more visually stimulated than women, their brains dole out bigger doses of monoamines [source: Obringer].