The authors present an unusual case of a healthy young male who developed a spontaneous subdural haematoma. Headache was followed by blurring of vision and left upper limb symptoms. The diagnosis was made from a CT scan. Symptoms resolved with surgical decompression. The authors explore the risk factors and pathophysiology implicated in this condition. The authors demonstrate that apparently 'healthy' pursuits can have significant consequences, but the physician must also exclude serious underlying risk factors for bleeding, which the authors discuss.