with hyperhidrosis. for example, careers that require the use of a knife may not be safely performed by people with excessive sweating of the hands. the risk of dehydration can limit the ability of some to function in extremely hot (especially if also humid) conditions. even the playing of musical instruments can be uncomfortable or difficult because of sweaty hands. epidemiology it is estimated that the incidence of focal hyperhidrosis may be as high as 2.8% of the population of the united states. it affects men and women equally, and most commonly occurs among people aged 25–64 years, though some may have been affected since early childhood. about 30–50% of people have another family member affected, implying a genetic predisposition. in 2006, researchers at saga university in japan reported that primary palmar hyperhidrosis maps to gene locus 14q11.2–q13.