Strenuous, intensive, long-term exercise does not prevent or delay the onset of Huntington's disease

Recent work in mice has suggested that an enriched environment can delay disease onset in models of Huntington's disease (HID). The component of an enriched environment most likely able to be translated to humans is increased exercise. But here I note that a recently reported case of HID in a marathon runner who had, for many years before becoming symptomatic with HD, been running at an advanced amateur/semiprofessional level, suggests that in humans exercise is not able to prevent or even delay onset of HD. In general study of marathon runners may be useful to study if exercise can prevent or delay onset of genetic diseases. (c) 2006 Elsevier Ltd. All rights reserved.