Effects of a nap on nighttime sleep and waking function in older subjects.

OBJECTIVES

To examine, in older subjects, the effect on waking function of increasing 24-hour sleep amounts by providing a nap opportunity; to assess what effects an afternoon nap may have on subsequent nighttime sleep quality and composition.

DESIGN

Two-session, within-subject laboratory design.

SETTING

The study was conducted in the Laboratory of Human Chronobiology at Weill Cornell Medical College.

PARTICIPANTS

Thirty-two healthy men and women aged 55 to 85.

MEASUREMENTS

Polysomnography (sleep electroencephalogram), cognitive and psychomotor performance, body core temperature.

RESULTS

Napping had little effect on subsequent nighttime sleep quality or duration, resulting in a significant increase in 24-hour sleep amounts. Such increased sleep resulted in enhanced cognitive and psychomotor performance immediately after the nap and throughout the next day.

CONCLUSION

A behavioral approach that adds daytime sleep to the 24-hour sleep quota seems worthy of consideration when presented with a situation in which physiological changes associated with aging may limit the duration of nighttime sleep.