The Importance of REM and Deep Sleep — and How to Improve Them

A person peacefully sleeping in bed, indicating deep sleep or REM stages essential for rest and recovery.

Getting a full night’s rest isn’t just about how long you sleep—it's about how well you move through your sleep stages. Two of the most critical stages for your health are REM (Rapid Eye Movement) and deep sleep (also called slow-wave sleep or SWS). Both are essential for brain performance, memory, emotional regulation, and long-term disease prevention.

Let’s dive into what science says about these stages—and what you can do to improve them.

What Is REM Sleep?

REM sleep is a mentally active stage that occurs in cycles throughout the night, increasing in length with each cycle. It's when most dreaming occurs and is marked by rapid eye movements, low muscle tone, and fast brain activity.

Why REM Sleep Is Important:

• Emotional Processing & MoodREM sleep helps regulate emotional reactivity by balancing limbic and prefrontal activity. Chronic REM deprivation is linked to anxiety and depression.(Goldstein & Walker, 2014)

• Learning and Memory ConsolidationREM strengthens emotional and procedural (skill-based) memories. It's particularly important for integrating memories into existing knowledge.(Rasch & Born, 2013; Boyce et al., 2016)

• Creativity & Problem-SolvingREM sleep promotes flexible thinking and novel idea formation through unique brainwave activity.(Cai et al., 2009)

  
  

What Is Deep Sleep?

Deep sleep (also called slow-wave sleep or N3) occurs in the early part of the night. It’s characterized by large, slow brain waves and reduced heart rate and breathing.

Why Deep Sleep Is Important:

• Memory StabilizationIt plays a key role in consolidating declarative (fact-based) memories.(Diekelmann & Born, 2010)

• Physical Recovery & Immune HealthGrowth hormone release, cellular repair, and immune restoration all occur during this stage.(Besedovsky et al., 2012)

• Brain DetoxificationDuring deep sleep, the brain clears toxins like beta-amyloid via the glymphatic system—this may reduce Alzheimer’s risk.(Xie et al., 2013)

  
  

REM vs. Deep Sleep at a Glance

Feature	REM Sleep	Deep Sleep (SWS)
Brain Waves	Fast, similar to wakefulness	Slow delta waves
When It Occurs	Later in the night	First half of the night
Key Functions	Emotional memory, creativity	Physical repair, memory, detox
Sleep Cycle %	~20–25% of total sleep	~15–20% of total sleep

Science-Backed Tips: how to Improve REM & Deep Sleep

1. Stick to a Consistent Sleep Schedule

Going to bed and waking up at the same time daily improves sleep efficiency and supports full sleep cycles.(Walker et al., 2020)

2. Limit Caffeine and Alcohol

Caffeine blocks adenosine (the sleep drive chemical) and alcohol suppresses REM and deep sleep—even if it helps you fall asleep.(Roehrs & Roth, 2001; Ebrahim et al., 2013)

3. Get Morning Light Exposure

Daylight in the early morning helps anchor your circadian rhythm, which governs REM timing.(Wright et al., 2013)

4. Avoid Screens Before Bed

Blue light suppresses melatonin, which delays REM and reduces total sleep quality.(Chang et al., 2015)

5. Try Gentle Wind-Down Rituals

Practices like stretching, mindfulness meditation, or reading improve SWS and help transition to deeper sleep.(Ong et al., 2014)

6. Consider Targeted Memory Reactivation (TMR)

In some sleep labs, people exposed to subtle cues (like sounds) during sleep showed enhanced memory consolidation—especially during REM.(Antony et al., 2012; Schreiner & Rasch, 2015)

FAQs

Q: How much REM and deep sleep do I need?A healthy adult should get 7–9 hours of sleep, with roughly 1.5–2 hours in REM and 1–2 hours in deep sleep each night.

Q: Can I “make up” lost REM or deep sleep?To some extent, your body may “rebound” by spending more time in missed stages, but chronic deprivation can’t be fully undone.

Q: Are sleep trackers accurate?Most consumer trackers estimate sleep stages based on heart rate and movement—they’re decent, but not as accurate as medical-grade polysomnography.

Q: Should I take melatonin?Melatonin can help adjust your circadian rhythm but doesn’t directly boost REM or deep sleep. Use under a doctor’s guidance.

References

1. Goldstein, A. N., & Walker, M. P. (2014). The role of sleep in emotional brain function. Annual Review of Clinical Psychology, 10, 679–708.

2. Rasch, B., & Born, J. (2013). About sleep's role in memory. Physiological Reviews, 93(2), 681–766.

3. Boyce, R., et al. (2016). Causal evidence for the role of REM sleep theta rhythm in contextual memory consolidation. Science, 352(6287), 812–816.

4. Cai, D. J., et al. (2009). REM, not incubation, improves creativity by priming associative networks. PNAS, 106(25), 10130–10134.

5. Diekelmann, S., & Born, J. (2010). The memory function of sleep. Nature Reviews Neuroscience, 11(2), 114–126.

6. Besedovsky, L., et al. (2012). Sleep and immune function. Pflugers Archiv, 463, 121–137.

7. Xie, L., et al. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156), 373–377.

8. Walker, M. P., et al. (2020). Circadian rhythms and sleep. The Lancet Neurology, 19(9), 747–757.

9. Roehrs, T., & Roth, T. (2001). Caffeine: sleep and daytime sleepiness. Sleep Medicine Reviews, 5(2), 145–155.

10. Ebrahim, I. O., et al. (2013). Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical & Experimental Research, 37(4), 539–549.

11. Wright, K. P., et al. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology, 23(16), 1554–1558.

12. Chang, A. M., et al. (2015). Evening use of light-emitting eReaders negatively affects sleep. PNAS, 112(4), 1232–1237.

13. Ong, J. C., et al. (2014). Mindfulness meditation and cognitive behavioral therapy for insomnia. Journal of Clinical Psychology, 70(6), 563–579.

14. Antony, J. W., et al. (2012). Cued memory reactivation during sleep influences skill learning. Nature Neuroscience, 15(8), 1114–1116.

15. Schreiner, T., & Rasch, B. (2015). Boosting vocabulary learning by verbal cueing during sleep. Cerebral Cortex, 25(11), 4169–4179.