Improvement in sleep duration was associated with higher cognitive function: a new association.

Area of Science:

• Neuroscience
• Gerontology
• Sleep Science

Background:

• Previous research suggests a link between sleep duration and cognitive performance.
• Understanding how changes in sleep impact cognition is crucial for public health.

Purpose of the Study:

• To investigate the association between changes in sleep duration and cognitive function.
• To determine optimal sleep duration for cognitive health in older adults.

Main Methods:

• Analysis of data from 10,325 adults aged 45+ from the China Health and Retirement Longitudinal Study (CHARLS).
• Self-reported nocturnal sleep duration and cognitive function (global score including memory, attention, etc.) assessed over three waves (2011-2015).

Main Results:

• Transitioning from short sleep duration (SSD) to moderate sleep duration (MSD) improved global cognition (β=0.54, P<0.01).
• Shifts from SSD to long sleep duration (LSD) or LSD to SSD were linked to lower cognition (β=-0.94, P<0.001 and β=-1.38, P<0.01, respectively).
• For those with MSD, a significant increase or decrease (≥2h) in sleep duration was associated with poorer cognitive function (β=-0.89, P<0.001 and β=-0.70, P<0.001).

Conclusions:

• For individuals with short sleep duration, increasing sleep is beneficial for cognitive function.
• Long sleepers did not require sleep reduction; however, substantial deviations from moderate sleep duration were detrimental to cognition.