Health & Wellness

The Surprising Link Between Sleep and Intelligence

Rankd Team · 6 min read

Sleep Is Brain Maintenance

During deep sleep, your brain clears metabolic waste through the glymphatic system, consolidates memories, and strengthens neural connections. Cutting sleep short literally means running your brain without maintenance — and the cognitive costs are immediate and cumulative.

How Much IQ Points Cost You

One night of poor sleep reduces cognitive performance by the equivalent of 5-8 IQ points. Chronic sleep deprivation (less than 6 hours regularly) produces cognitive impairment comparable to being legally drunk. You can't think clearly if you're not sleeping well.

The Optimization

Seven to nine hours of quality sleep in a consistent schedule produces the best cognitive performance. No supplement, nootropic, or brain training app comes close to the cognitive benefit of simply sleeping properly.

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