8 Practical Tips to Increase Deep Sleep
Somewhere between falling asleep and waking up, your body is supposed to do something remarkable: your brain clears out built-up waste through the glymphatic system, your muscles repair and grow, your memories are sorted and stored, and your immune system resets for the day ahead. It's one of the most complex biological processes in the human body, and it happens without you even noticing.
Unless, of course, it doesn't happen properly. Sometimes, even after eight hours of sleep, you don’t feel rested. If that sounds familiar, the reason may not be how long you slept but whether you’re getting enough of the deep sleep stage.
Key Learnings
- Deep sleep makes up only 13–23% of your night, but it's when growth hormone is released, memories are consolidated, and your brain literally flushes out waste.
- Just 30 minutes on your phone in bed costs you roughly 20 minutes of deep sleep.
- Exercising 4x a week for under 30 minutes per session is one of the proven ways to improve deep sleep quality from the very first week.
4 Stages of Sleep
You cycle through sleep stages roughly every 90 minutes. Every night, your brain cycles through four distinct stages:
- Stage 1 (N1): Light sleep. The transition between wakefulness and sleep. Your muscles relax, your heart rate slows, and you can be woken easily. This lasts just a few minutes and makes up a small fraction of your total sleep.
- Stage 2 (N2): Deeper light sleep. Your body temperature drops, your eye movements stop, and your brain begins producing bursts of activity called sleep spindles. This stage takes 45–55% of total sleep time.
- Stage 3 (N3): Deep sleep, or slow-wave sleep (SWS). This is the one that matters most for physical and cognitive restoration. Your brain activity slows to long, rolling waves, your muscles fully relax, and growth hormone is released.
- REM sleep: Rapid Eye Movement. Your brain becomes nearly as active as when you're awake. This is when most vivid dreaming happens, and it's critical for emotional processing, creativity, and long-term memory integration. REM sleep is concentrated in the second half of the night.
What Happens During Deep Sleep
That foggy, heavy feeling after a full night? That's what deep sleep deprivation feels like.
Adults typically need 1 to 2 hours of deep sleep per night, which is about 18 to 22% of total sleep time. That proportion naturally decreases with age, but the lifestyle factors working against it are, in most cases, completely reversible.
Deep sleep is your body's nightly repair window. During deep NREM sleep, your brain activates the glymphatic system. It’s a waste-clearance mechanism that flushes out toxic metabolic byproducts that accumulate during the day, including proteins linked to neurodegenerative disease. Simultaneously, your muscles repair micro-tears, your immune system consolidates its defenses, and growth hormone is released in its largest pulse of the day.
When slow-wave activity in the brain was selectively disrupted, people's capacity to learn and form new neural connections dropped, even if their total sleep time looked normal.
Why You Might Not Be Getting Enough Deep Sleep
Before diving into deep sleep tips, it helps to understand what's working against you. Deep sleep results from physiological, environmental, and behavioral factors that your body responds to.
- Screen time in bed. Spending 30 minutes on your phone in bed was associated with around 20 fewer minutes of deep sleep.
- Alcohol. It might make you feel drowsy, but alcohol fragments the later stages of sleep and reduces time in deep sleep.
- Irregular sleep schedules. Your body needs a consistent circadian anchor. When your wake time shifts by more than an hour across the week, this impacts deep sleep.
- Chronic stress. Elevated evening cortisol is among the most well-documented inhibitors of slow-wave sleep.
8 Ways to Improve Deep Sleep Naturally
1. Add exercise to your routine
If you change one thing, make it this. Regular exercise has a clear, consistent effect on deep sleep, especially when it’s done a few times a week at moderate intensity. Regular exercise improves the stability and quality of slow-wave sleep. Keep workouts relatively short (under 30 minutes) to avoid the cortisol spike that longer, intense workouts can trigger, and let your body settle before bed.
2. Keep your bedroom cool
Your body needs to lower its core temperature to enter deep sleep. A cool room (around 65-68°F / 18-20°C) helps that happen naturally. A warm shower or bath 1-2 hours before bed helps too: the vasodilation it triggers accelerates heat loss from your skin, speeding up how quickly your body cools afterward.
3. Dim the lights at night
Light in the evening tells your brain it’s still daytime, even if you feel tired. Bright, blue-heavy light in particular can delay sleep and make it harder to reach deeper stages of sleep. Lowering the lights and getting some morning sunlight helps keep your internal clock on track.
4. Create a wind-down ritual
Sleep isn’t an on/off switch. You need a transition. Doing the same few low-effort things each night, like reading, stretching, or writing things down, gives your brain a clear signal that the day is ending. Over time, that routine becomes almost automatic. You can use Liven's Journal to write down any thoughts or reflections you might have before going to sleep.
"My insomniac clients enjoy creating their own calming ritual before bed. Writing three things they are grateful for, drinking herbal tea like chamomile, listening to a short, happy meditation, and then reading something positive and inspirational. Try one or a few of these to lower stress and sleep more deeply." — Kathryn Remati, Health Educator, Meditation & Sleep Expert
5. Be mindful of food and caffeine
Eating too close to bedtime keeps your body busy when it should be slowing down. Caffeine has a longer half-life than you think, about 5-6 hours. That 3 pm coffee is still partially in your system at 9 pm when you should start winding down for sleep.
6. Clear your mind before bed
A busy or anxious mind doesn’t just disappear when you lie down. Taking a few minutes to slow down through breathing, journaling, or body scan meditation can make it much easier to fall into deeper sleep.
7. Keep your schedule steady
Dr. Christy Kestner explains that two things control sleep: your circadian rhythm (your internal clock) and sleep pressure (how long you’ve been awake). When bedtime and wake time keep shifting, your brain stops getting a clear rhythm cut, so sleep feels unpredictable. The fix is usually to anchor your wake-up time first, rather than chasing the perfect bedtime. Wake up at the same time every day, get morning light soon after waking up, and let your bedtime gradually stabilize from there.
8. Keep your room dark and quiet
Your brain stays more alert than you think when there’s light or noise in the background. Even small interruptions can keep you in a lighter state of sleep without fully waking you. A darker, quieter space helps you stay in deeper sleep longer.
How to Know That Your Deep Sleep Has Improved
Wearables can give you a rough sense of sleep trends, but research is clear that consumer devices tend to overestimate deep sleep compared to clinical sleep studies.
More reliable signals that your deep sleep is improving:
- Waking up genuinely rested without needing an alarm
- Fewer midnight wake-ups
- Less grogginess in the first 30 minutes after waking
- Better mood, focus, and physical recovery across the day
Track these over 2-3 weeks after you make a change. That feedback is more honest than any percentage on a sleep app.
Where to Start?
You don't need to overhaul everything at once. Pick the one change that feels most actionable: a consistent wake time, a cooler bedroom, or an evening walk. Give it two weeks. Real changes in sleep routine may take time to show up.
If you'd like that one change shaped around your week, Liven's short quiz puts together your personalized wellbeing management plan with daily check-ins that can help you build steadier sleep over time.
Sleep is something you build night by night, choice by choice.
References
1. Patel, A.K., Reddy, V., & Araujo, J.F. (2022, September 7). Physiology, sleep stages. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK526132/
2. Fattinger, S., De Beukelaar, T. T., Ruddy, K. L., Volk, C., Heyse, N. C., Herbst, J. A., Hahnloser, R. H. R., Wenderoth, N., & Huber, R. (2017). Deep sleep maintains learning efficiency of the human brain. Nature Communications, 8(1), 15405. https://doi.org/10.1038/ncomms15405
3. Lustenberger, C., Ferster, M. L., Huwiler, S., Brogli, L., Werth, E., Huber, R., & Karlen, W. (2022). Auditory deep sleep stimulation in older adults at home: a randomized crossover trial. Communications Medicine, 2(1), 30. https://doi.org/10.1038/s43856-022-00096-6
4. Yue, T., Liu, X., Gao, Q., & Wang, Y. (2022). Different intensities of evening exercise on sleep in healthy adults: a systematic review and network meta-analysis. Nature and Science of Sleep, 14, 2157–2177. https://doi.org/10.2147/NSS.S388863
5. Finucane, E., O’Brien, A., Treweek, S., Newell, J., Das, K., Chapman, S., Wicks, P., Galvin, S., Healy, P., Biesty, L., Gillies, K., Noel-Storr, A., Gardner, H., O’Reilly, M. F., & Devane, D. (2021). Does reading a book in bed make a difference to sleep in comparison to not reading a book in bed? The People’s Trial—an online, pragmatic, randomized trial. Trials, 22(1), 873. https://doi.org/10.1186/s13063-021-05831-3
FAQ: How to Increase Deep Sleep
Can naps replace deep sleep at night?
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Why do I wake up tired even after 8 hours?
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