A minority of upper extremity DVTs are due to Paget–Schroetter disease, also called effort thrombosis, which is a rare (1–2 people out of 100,000 a year) and serious form of arm DVT that typically occurs in athletic males around 30 years of age, especially "swimmers, weightlifters, and javelin throwers" or in those who do significant amounts of overhead work, such as electricians and mechanics.