Deep sleep, or slow-wave sleep, is the most restorative sleep stage where the body repairs tissues, builds bone and muscle, and strengthens the immune system.

How much deep sleep should you get per night?

Adults typically get 1–2 hours of deep sleep per night, which makes up about 13–23% of total sleep time.

What causes lack of deep sleep?

Common causes include stress, caffeine, alcohol, poor sleep habits, ageing, sleep disorders, and an unsuitable sleep environment.

How can I get more deep sleep?

Stick to a regular schedule, reduce caffeine and alcohol, optimise your sleep environment, exercise, and try relaxation techniques.

Can supplements help with deep sleep?

Yes, supplements like magnesium, glycine, and valerian root may support deep sleep, but always consult a healthcare professional first.

Why You’re Not Getting Deep Sleep – And What to Do About It

A person in a blue hoodie covers their face with hands, sitting on a sofa. Open boxes and a yellow cushion in the background suggest stress.

Struggling to wake up feeling refreshed? You’re not alone. Many people get their 7 to 8 hours in, yet still feel groggy and unrested. The culprit? A lack of deep sleep.

Deep sleep, also known as slow-wave sleep, is a critical phase of the sleep cycle where your body and brain undergo essential recovery. Without enough of it, even a full night’s sleep can leave you feeling like you barely got any rest at all.

In this guide, we’ll break down what deep sleep is, why you might not be getting enough, and how to improve it naturally.

What Is Deep Sleep?

Deep sleep is the third stage of non-REM (rapid eye movement) sleep. It’s the phase when brain waves slow down significantly, and your body gets busy repairing muscles, consolidating memories, and boosting immune function. During this stage, it’s hardest to wake up, and if you do, you’ll probably feel disoriented.

On average, adults spend about 13–23% of their total sleep in deep sleep. For someone sleeping 8 hours, that means roughly 1 to 2 hours of deep sleep per night. The amount naturally declines with age, but lifestyle factors can also reduce how much deep sleep you get.

Signs You’re Not Getting Enough Deep Sleep

Waking up feeling groggy or disoriented
Struggling with memory or concentration
Frequently getting sick or feeling run down
Muscle soreness that doesn't go away
Low energy levels despite sleeping 7–8 hours

These symptoms can indicate that your sleep quality is poor, even if you’re hitting your target sleep duration.

Causes of Poor Deep Sleep

1. Stress and Anxiety

High cortisol levels, often linked to chronic stress, can interfere with your ability to enter or maintain deep sleep. An overactive mind makes it difficult for the body to fully relax into the deeper stages of rest.

2. Sleep Environment

Noise, light pollution, uncomfortable mattresses, or even the wrong room temperature can all impact your sleep stages. Deep sleep thrives in cool, dark, and quiet environments.

3. Irregular Sleep Schedule

Your body runs on a circadian rhythm. Constantly changing bedtimes or wake times disrupt this rhythm and reduce the time spent in restorative deep sleep.

4. Caffeine and Alcohol

Both can affect your sleep architecture. Caffeine is a stimulant that delays sleep onset, while alcohol might help you fall asleep quickly but reduces REM and deep sleep later in the night.

5. Sleep Disorders

Conditions like sleep apnea and restless leg syndrome can fragment your sleep, preventing the body from reaching or staying in deep sleep phases.

6. Ageing

As you age, the amount of deep sleep you get naturally decreases. While this is normal, it makes other contributing factors even more important to address.

How to Get More Deep Sleep

1. Stick to a Regular Schedule

Going to bed and waking up at the same time each day helps regulate your circadian rhythm and supports all stages of sleep, especially deep sleep.

2. Optimise Your Sleep Environment

Keep your room cool (around 16-18°C)
Use blackout curtains to block out light
Invest in a comfortable mattress and pillow
Use earplugs or a white noise machine if noise is an issue

3. Limit Caffeine and Alcohol Intake

Avoid caffeine after 2pm and limit alcohol in the evening. This reduces interference with your sleep cycle.

4. Exercise Regularly

Daily physical activity has been shown to increase the amount of deep sleep. Just make sure to avoid intense workouts too close to bedtime.

5. Relax Before Bed

Engage in calming activities like reading, light stretching, deep breathing, or meditation before sleep. This helps lower cortisol and prepares your body for rest.

6. Consider Sleep Supplements

Supplements like magnesium, glycine, or valerian root have been associated with improved sleep quality. Always speak to a healthcare provider before adding any supplement to your routine.

7. Evaluate for Sleep Disorders

If you're doing everything right and still waking up exhausted, it might be time to speak to a doctor or sleep specialist. A sleep study can rule out conditions like sleep apnea.

Final Thoughts

Not getting enough deep sleep can have a serious impact on your physical health, cognitive function, and overall quality of life. While ageing plays a role, many lifestyle and environmental factors are within your control. Small, consistent changes can lead to noticeable improvements in your sleep quality.

If you wake up tired every day, don’t just assume you’re not a "morning person." You might simply be missing out on the most restorative part of sleep.