5 Sleep Facts You Probably Don’t Know — Including Why Women Need More Sleep Than Men

Health knowledge gaps are common, especially when it comes to sleep. Despite spending roughly a third of our lives asleep, most people have a surprisingly incomplete understanding of how it works. A physician recently filled in five important gaps — beginning with a finding that many find genuinely surprising: women need more sleep than men.
The difference amounts to about 20 additional minutes per night for women, the physician explains. The reason is cognitive: women, on average, engage in more multitasking throughout the day. This means the brain is working harder — simultaneously managing multiple streams of information and tasks — which in turn means it needs more time during sleep to consolidate, organize, and restore. The sleep requirement scales with the cognitive demand.
Sleep onset time is another important detail that most people have never been taught. The physician identifies the healthy range as 10 to 20 minutes. If you typically fall asleep faster than this, your body may be in a state of persistent sleep deprivation. If you regularly take longer, your system may be struggling to shift from an active, alert state into rest — a pattern associated with insomnia and other sleep disorders.
The near-total loss of dream memories is one of the most consistently fascinating aspects of sleep. About 95 percent of what we experience in our dreams is forgotten within minutes of waking. This happens because dreams occur in brain states that don’t effectively translate experiences into long-term memory. For anyone interested in their dreams, the physician’s advice is to write them down immediately upon waking, before the memories disappear entirely.
The final two facts are both actionable and illuminating. Seventeen consecutive hours of wakefulness produces cognitive impairment comparable to a blood alcohol level of 0.05 percent — meaningful enough to affect driving, judgment, and complex thinking. And with melatonin, bigger doses aren’t better: 0.5 mg aligns with the body’s natural production and tends to be more effective than the much higher doses commonly sold in stores.