Skip to main content

Why At Least 7 Hours of Sleep Is Essential for Brain Health

Have you ever stayed up late when you know you shouldn’t? If you have, you're not alone.

Learn about current research regarding sleep duration, how it could connect to racial/ethnic health disparities, and how sleep affects the brain overall.

Why At Least 7 Hours of Sleep Is Essential for Brain Health

Department Contributor: Kathleen Digre, MD

Woman sleeping

Have you ever stayed up late when you know you shouldn’t? If you have, you’re not alone—according to the Centers for Disease Control and Prevention, a third of all adults in the United States have reported that they don’t get enough sleep.

This idea is further supported by the research conducted in the study “Short Sleep Duration and Interest in Sleep Improvement in a Multi-Ethnic Cohort of Diverse Women Participating in a Community-Based Wellness Intervention: An Unmet Need for Improvement,” which found that out of 485 women of color, 199 (41%) reported “short sleep duration,” which is defined as seven hours or less. The article also went on to report that only 10.7% of the participants expressed interest in sleep improvement, and highlighted the divide between need and interest when it comes to improving sleep habits.

This study’s researchers, including the University of Utah Department of Neurology’s Kathleen Digre, MD, were also concerned that short sleep duration may be a factor that contributes to racial/ethnic health disparities. After all, it is well documented that Black/African Americans are nearly twice as likely to have shorter sleep durations than Hispanics/Latinos and non-Hispanic Whites; in the same vein, Hispanics/Latinos have higher rates of short sleep when compared to non-Hispanic Whites. However, to date, few studies have examined community perceptions and needs for sleep interventions, and this scarcity is a major limiting factor to the development of sleep interventions among communities of color—a gap that this study sought to fill. To reach this goal, these researchers completed a randomized trial of a one-year community-based wellness intervention that enrolled a multi-ethnic sample. The “wellness intervention” included working with community members to identify needs and then designing and implementing interventions collaboratively.

But 6 Hours Feels Like Enough for Me

It is a common belief that while consistently undersleeping isn’t optimal, it’s not a big deal in the long term. The Sleep Foundation lists the most common causes of short sleep duration as poor sleep hygiene (e.g., deciding to stay up late to binge-watch a TV series or interacting with electronic devices), lifestyle choices (e.g., staying out late with friends), work obligations (multiple jobs or shift work), sleep disorders (e.g., insomnia), and other medical conditions (e.g., migraine or sleep apnea). Any one of these factors can result in the loss of an hour or two of shut-eye. 

However, the belief that 5–7 hours of sleep is sufficient has been increasingly disproved in the past ten years; several studies have found that sleep deficiency can lead to serious outcomes such as obesity, hypertension, type 2 diabetes, stroke, and neurodegenerative disorders. Depression symptoms and low stress management are also associated with short sleep duration.

The Benefits of a Good Night’s Rest

Sleep is essential to the functioning and health of the brain. There’s a lot that goes on while we’re dreaming—more than just resting the body (though that is also important!). Sleep allows a number of processes to run and develop, and without them, our brains start to go a little haywire.

How Sleep Benefits Your Brain
  1. Restoration and repair: Sleep provides an opportunity for the brain to restore and repair itself. During sleep, the brain clears out waste products and toxins that accumulate throughout the day. This process is performed by the glymphatic system.
  2. Memory consolidation: Sleep plays a crucial role in memory consolidation, which is the process of strengthening and integrating newly acquired information into long-term memory. Different stages of sleep, particularly rapid eye movement (REM) sleep and slow-wave sleep (SWS), are associated with different aspects of memory consolidation.
  3. Cognitive performance: A good night's sleep enhances cognitive abilities, creativity, and overall mental performance. Sleep deprivation or insufficient sleep can lead to a decreased attention span, impaired concentration, reduced decision-making abilities, and difficulties with learning and problem-solving. 
  4. Brain development: Sleep is one of the primary activities of the brain during early development and plays an important role in healthy cognitive and psychosocial development in early life. This study found differences in brain function, behavior, and mental health between children who get nine hours of sleep at night and children who get less. 
  5. Emotional regulation: Sufficient sleep also helps regulate emotions, while sleep deprivation can lead to increased emotional reactivity, mood swings, irritability, and heightened stress responses. Sleep disturbances are also associated with a higher risk of developing mood disorders, such as depression and anxiety.

Your commitment to sleep affects your brain health throughout your life! So the next time you’re tempted to stay awake past your bedtime, turn off the light and take care of your mind instead.

Additional Resources

Migraine & Sleep: In this video, University of Utah Neurologist Jyotika Singh, DO, talks about what those with chronic migraine and headache can try for better sleep.

5 Tips for Better Sleep

Conversations to Improve Sleep for Bed Partners

Want More NeurologyNews?
Stay up to date on the Department of Neurology's latest announcements, research, and events by signing up for our monthly newsletter!