How to Increase Deep Sleep: A Complete Guide to Sleeping Better in 2025

Deep sleep is the gold standard of restorative rest. It is during this stage that the body repairs tissues, consolidates memories, and releases growth hormones. But for many people, getting enough deep sleep feels increasingly out of reach.

Modern stress, artificial lighting, and poor lifestyle habits all conspire to reduce the time spent in this vital stage.

This guide will break down exactly how to increase deep sleep, with practical, science-backed advice.

What Is Deep Sleep?

Deep sleep, also known as slow-wave sleep (SWS) or Stage 3 non-REM sleep, is characterised by delta brainwaves. During this stage, muscle repair and tissue growth occur, immune function strengthens, memory consolidation happens, and growth hormone is released.

How much deep sleep do you need?

According to the NHS, adults typically need between seven to nine hours of total sleep per night, with around 13% to 23% of that ideally spent in deep sleep.

Why Deep Sleep Matters

Poor deep sleep is linked to an increased risk of chronic illnesses like diabetes and heart disease, impaired cognitive function, mood disturbances, and a weakened immune system.

A 2020 review published in Nature and Science of Sleep found that insufficient deep sleep is correlated with an increased risk of Alzheimer’s disease.

Signs of Deep Sleep Deficiency

Not sure if enough deep sleep is being achieved? Some common signs include waking up feeling unrefreshed, daytime fatigue, memory lapses, poor mood regulation, and increased susceptibility to infections.

Devices like the Oura Ring or the WHOOP Strap can estimate time spent in deep sleep, although polysomnography in a sleep lab remains the gold standard.

How to Increase Deep Sleep Naturally

Alcohol is a deep sleep killer - cut back to increase your restorative sleep

Optimise Sleep Schedule

Keeping a consistent sleep schedule helps regulate the circadian rhythm. The Sleep Foundation recommends waking up and going to bed at the same time every day, even on weekends. Target between seven to nine hours of sleep each night and aim to prioritise sleep before midnight, when deep sleep is most abundant.

Create a Deep Sleep-Friendly Bedroom

Environmental factors can significantly influence deep sleep quality. Maintaining a cool bedroom temperature of around 16-18°C, ensuring total darkness with blackout curtains or an eye mask, reducing noise using earplugs or white noise machines, and investing in a supportive mattress and pillow can make a considerable difference.

Related guide: [Best Pillow for Neck Support]

Cut Back on Caffeine and Alcohol

Caffeine can linger in the system for up to ten hours, reducing time spent in deep sleep. A 2013 study in the Journal of Clinical Sleep Medicine found that caffeine consumed even six hours before bedtime can disrupt sleep. Alcohol, while helping with sleep onset, fragments sleep architecture and reduces deep sleep quality.

Exercise Regularly — But Not Too Late

Exercise improves deep sleep, particularly aerobic and resistance training. The NHS recommends at least 150 minutes of moderate-intensity exercise per week. However, exercising too close to bedtime can raise cortisol and adrenaline levels, making it harder to enter deep sleep.

Try Deep Sleep-Supportive Supplements

Certain supplements have been shown to promote deep sleep. Magnesium supports muscle relaxation and regulates GABA; glycine may lower core body temperature and promote sleep onset; valerian root has shown promise in improving sleep quality; and sleep gummies often contain natural ingredients like melatonin or magnesium. Always consult a healthcare professional before starting new supplements.

Manage Stress Levels

Stress elevates cortisol, a hormone that disrupts sleep. Effective stress management techniques include mindfulness meditation, yoga, journaling, and deep breathing exercises. A 2015 study published in JAMA Internal Medicine found that mindfulness meditation significantly improved sleep quality.

Apps like Calm and Headspace offer guided sleep meditations designed to increase relaxation.

Improve Sleep Hygiene

Good sleep hygiene practices can significantly impact deep sleep quality. These include avoiding screens one to two hours before bed, establishing a calming pre-sleep routine, and limiting naps to under 30 minutes during the day.

Light Exposure Timing

Morning sunlight exposure helps regulate melatonin production, improving deep sleep at night. A 2019 study in Sleep Health found that greater natural light exposure correlates with better sleep quality. In the evening, avoiding bright lights and considering warm-tone lamps or blue-light-blocking glasses can also support natural sleep rhythms.

Limit Food and Drink Before Bed

Large meals close to bedtime can increase metabolic activity and interfere with deep sleep. Alcohol and heavy, spicy foods are particularly disruptive. Aim to finish eating two to three hours before going to bed to allow digestion to complete.

Emerging Therapies for Deep Sleep Enhancement

Brainwave Entrainment

Techniques like binaural beats and pink noise have shown promise in improving deep sleep. Binaural beats are auditory illusions that may stimulate delta brainwave activity. Pink noise, when delivered in carefully timed bursts synchronised to brain activity, has been shown to enhance slow-wave sleep and memory consolidation. A 2017 study published in Frontiers in Human Neuroscience by Papalambros et al. found that acoustic stimulation with pink noise increased slow-wave activity and improved memory recall in older adults (source).

However, continuous overnight exposure to pink noise without synchronisation may not provide the same benefits and could even impair certain types of cognitive insight, according to later research.

Sleep Tech Gadgets

New wearable and non-invasive technologies aim to stimulate slow-wave sleep. These include headbands that emit low-frequency pulses designed to enhance deep sleep. Although still an emerging field, early results are encouraging.

When to See a Doctor

If consistently struggling to achieve restful sleep despite making lifestyle changes, it may be time to seek professional help. Potential underlying issues include sleep apnoea, restless legs syndrome, depression or anxiety disorders, and chronic pain. Consulting a GP or a sleep specialist can help uncover and address these issues.

Final Thoughts: Deep Sleep is Achievable

Increasing deep sleep is less about quick fixes and more about consistent daily habits. By improving sleep hygiene, managing stress, optimising the sleep environment, and considering supportive supplements, it is possible to significantly enhance sleep quality.

Deep sleep is the foundation of health. Prioritising it will pay dividends across every area of life — physically, mentally, and emotionally.

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FAQs About Increasing Deep Sleep

How much deep sleep do adults need?

Adults typically need between one to two hours of deep sleep per night, although this can vary.

Does melatonin increase deep sleep?

Can certain foods help increase deep sleep?

Is it normal for deep sleep to decrease with age?