This condition overlaps with temporal arteritis in many respects. Both occur in the same age group and both have the same general systemic symptoms and laboratory abnormalities, including elevated ESR, in about the same frequency. The major difference is that the principal symptom of polymyalgia is aching and stiffness in proximal joints such as the shoulders or hips; this condition is more noticeable after a period of inactivity, especially after sleep. Besides overlap in systemic symptoms and laboratory results with temporal arteritis, about 50% (range, 40%-60%) of patients with giant cell arteritis have symptoms compatible with polymyalgia rheumatica, and about 15% of patients (range, 10%-40%) with typical symptoms of polymyalgia (and normal-appearing temporal arteries on physical examination) have temporal artery biopsy findings of giant cell arteritis. It is controversial, however, whether to biopsy a temporal artery if the patient does not have any symptoms suggesting temporal arteritis.