Postambulatory swollen hands (POTASH), also known as big hand syndrome, refers to the acute onset of unilateral or bilateral hand swelling after beginning physical activity.

It is an uncommon condition, but it is reported to be more common in women younger than 60 years and to people who exercise outdoors, including runners, hikers, and dog walkers. POTASH typically manifests within the first hour of activity and resolves within a few hours after activity. The extent of swelling varies and may be limited to the hands and/or digits. Edema may be more severe after a longer duration of activity. Geographic location, exposure to heat / cold, and varying degrees of elevation do not seem to impact the resultant hand swelling. The specific pathogenesis of POTASH has yet to be established.