CHANGES IN CIRCADIAN-RHYTHMS AND SLEEP QUALITY WITH AGING - MECHANISMS AND INTERVENTIONS

Literature is reviewed indicating that aging is characterized by chang es in circadian rhythms and sleep quality. The most marked change is a n attenuation of amplitude. An advance of phase, a shortening of perio d, and a desynchronization of rhythms are also evident. The mechanisms underlying these changes are unknown. However, age-related changes in the retina, suprachiasmatic nucleus, and pineal gland seem relevant a long with behavioral changes such as a reduction in physical activity and exposure to photic stimulation. Changes in circadian rhythms are f requently associated with a reduction in nighttime sleep quality, a de crease in daytime alertness, and an attenuation in cognitive performan ce; reversing such changes could enhance the quality of life for a lar ge and rapidly increasing percentage of the population. Reversal appea rs possible by increasing melatonin levels with either appropriately t imed exposure to photic stimulation and/or appropriately timed adminis tration of exogenous melatonin. These interventions may increase aspec ts of genetic expression that have changed with aging. A hypothesis co ncerning the potential benefits of enhanced circadian amplitude is als o offered.