American scientists examined how the quality of nighttime rest affects mental functions the following day. The work’s findings appear in the journal Sleep Health.
Specifically, sleep fragmentation—that is, periods of wakefulness after falling asleep—directly correlates with thinking speed in older adults. However, the total number of sleep hours, bedtime, and daytime naps do not exert a significant impact on cognitive outcomes.
The study involved 261 individuals over 70 years old who lived independently. For 16 days, they wore devices enabling sleep monitoring and completed brief cognitive assessments on a smartphone several times daily. These tasks were designed to calculate information processing speed, evaluate visual working memory, and spatial reasoning. More than 20 thousand such tests were analyzed in total.
It emerged: when a person is awake at night for half an hour longer than their usual duration, their information processing speed noticeably declined the next day. Those whose sleep was more interrupted performed worse on several cognitive challenges. Recurring nocturnal awakenings greatly reduce the restorative effect of sleep.
The statistics are undeniable: roughly half of older adults experience sleep disruptions, but experts believe this issue is manageable. A doctor can help select accessible methods, including non-pharmacological ones. This can help postpone dementia.
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