Circadian rhythm of plasma cortisol in the aged (Cosinor method)

Plasma cortisol circadian rhythm was investigated in 18 apparently healthy elderly subjects, in 11 elderly patients affected by cerebrovascular hemiplegia and in 11 otherwise healthy blind elderly subjects. Results were microscopically analyzed by the least squares and Cosinor methods. The circadian rhythm of plasma cortisol was present and normal both in elderly subjects and in elderly patients with cerebrovascular hemiplegia. By contrast, a plasma cortisol rhythm was not found in blind elderly subjects.