MODIFICATIONS OF CIRCADIAN AND CIRCANNUAL RHYTHMS WITH AGING

Whereas biological rhythms are now fairly well documented in young hea lthy adults, reports in elderly are relatively few for obvious reasons , including the difficulty of setting groups matched in age, sociologi cal and professional background, medical history, and not in need of s pecific medication. Aging may modify one or several parameters charact erizing biological rhythms. The modifications are different from one f unction to the next, and great care should be given not to mistake cha nges attributable to the aging process with those resulting from physi cal and physiological impairment caused by passed environmental aggres sions and diseases. Nevertheless, the increasing number of subjects re aching the age of 65 or older, thanks to medical progress, makes neces sary establishing time-qualified references values in the aged, as thi s kind of investigation should lead to an improvement of the condition s and quality of life of elderly subjects. (C) 1997 Elsevier Science I nc.