Plasma norepinephrine in normal young and aged men: relationship with sleep

Area of Science:

• Neuroscience
• Gerontology
• Sleep Medicine

Background:

• Elevated plasma norepinephrine (NE) levels are associated with heightened sympathetic nervous system activity.
• Aging is often linked to changes in both sympathetic activity and sleep patterns.

Purpose of the Study:

• To investigate the relationship between age-related increases in plasma NE and sleep quality in older men.
• To determine if elevated NE levels contribute to sleep fragmentation in aging.

Main Methods:

• Compared 24-hour plasma NE levels and sleep patterns in 8 aged men and 10 young men.
• Monitored NE levels during various sleep-wake conditions, including natural sleep, awakenings, and reversed sleep/wake cycles.

Main Results:

• Aged men consistently showed significantly higher plasma NE levels than young men over 24 hours.
• The aged group experienced significantly more wakefulness while in bed.
• A significant positive correlation was found between higher plasma NE levels and increased wakefulness in the aged group.

Conclusions:

• Heightened sympathetic nervous system activity, reflected by elevated plasma NE, may contribute to sleep fragmentation in older adults.
• The observed sleep disturbances in aging are not solely due to altered sleep-wake cycles but are associated with increased sympathetic drive.