Sleep vs. screen - most of us suspect our phones aren’t great for sleep, yet they often end up beside us.
Sleep is often treated as expendable — something we sacrifice to meet work demands, social commitments, or late-night screen scrolling. Yet research shows that sleep is not wasted time but a vital biological process, essential for learning, memory, and long-term brain health. Around one-third of our lives is spent asleep, and scientists are discovering just how critical those hours are in protecting against neurological decline and supporting day-to-day functioning.
Why the brain needs sleep
Far from being passive, the brain remains highly active during sleep, cycling through slow-wave and rapid eye movement (REM) stages. Each stage plays a different role: Slow-wave sleep early in the night helps stabilise new memories, while REM sleep later in the night is linked to processing emotions, integrating experiences, and fostering creativity. Harvard neuroscientist Charles Czeisler calls these processes the brain’s way of transforming fragments of learning into cohesive understanding.
Sleep may also serve a vital housekeeping function. Some emerging research suggests the brain’s glymphatic system becomes more active at night, flushing out proteins and other waste products that, if allowed to build up, may contribute to neurodegenerative disease.
Cognition, Memory and Everyday Function
We feel the effects of poor sleep almost immediately: foggy thinking, lapses in concentration, and sluggish reactions. Studies
equate being awake for 18 hours with the impairment of a blood alcohol concentration of 0.05 and 2025 research from the University of Western Australia shows that mismatches between perceived and actual sleep are linked to poorer
cognitive outcomes.
Beyond tiredness, chronic sleep loss undermines decision-making. The Sleep Health Foundation cites brain imaging research that shows that sleep deprivation suppresses activity in areas that weigh risks while heightening sensitivity to rewards, leaving people more impulsive and error-prone.
Sleep also fuels creativity. Experiments confirm the wisdom of “sleeping on it”: the sleeping brain replays and reorganises memories, enabling fresh insights into problems.
Sleep supports brain health at every stage of life. The right amount — and quality — of sleep is vital for learning, memory, mood, and long-term brain health.
Rest and restore – children need more sleep than adults to fuel learning and growth.
For children and adolescents, adequate and regular sleep enhances learning, behaviour, and school performance.
Sleep and Teenagers: Why It Matters
Teenagers often don’t get enough sleep, and the effects are serious.
Irregular sleep: 40% of teens shift bedtimes by 2+ hours on weekends, disrupting their body clock.
Too little sleep: Many get under 8 hours on school nights.
Daytime effects: Poor sleep makes teens more likely to:
Struggle with concentration and memory in class.
Have lower school performance and grades.
Feel moody, irritable, or depressed.
Be late for school or skip it altogether.
Longer-term risks: Ongoing irregular sleep can contribute to depression and anxiety, and in severe cases may indicate sleep disorders like Delayed Sleep-Wake Phase Disorder.
Better habits: Keep bed/wake times consistent, avoid screens before bed, get morning sunlight and exercise, and seek help if sleep affects school or wellbeing.
In midlife, the quality and quantity of sleep become powerful predictors of brain health. An Australian National University study of 29,000 adults found that sleeping less than six hours or more than nine hours a night was associated with smaller brain volumes and poorer cognitive scores. Daytime dozing was also linked to impaired brain function.
In older age, sleep plays a protective role against cognitive decline. The Woolcock Institute’s Oracle Study is investigating how sleep disorders such as obstructive sleep apnoea (OSA) and chronic obstructive pulmonary disease (COPD) accelerate brain ageing, aiming to identify biomarkers for earlier intervention. Clinicians also recognise that excessive sleepiness or fragmented sleep can signal underlying neurological conditions, sometimes mimicking early dementia.
The Sleep Health Foundation recommends different amounts of sleep across the lifespan. School-aged children need 9–11 hours per night, while teenagers should aim for 8–10 hours. Young adults and adults typically require 7–9 hours, and older adults 7–8 hours. Meeting these targets helps support learning, mood, memory, and long-term brain health.
Sleepless and stressed – poor sleep makes it harder for young people to cope with everyday challenges.
Poor Sleep and Disease Risk
When sleep is consistently inadequate or disrupted, the consequences extend far beyond tiredness. Sleep deprivation impairs concentration, memory, and mood, but it is also linked to serious health outcomes. Chronic lack of sleep increases risks of obesity, hypercholesterolaemia, diabetes, hypertension, and cardiovascular disease.
Sleep problems are also common in neurological conditions. Parkinson’s disease is strongly associated with sleep disorders such as REM sleep behaviour disorder and excessive daytime sleepiness, which often precede diagnosis and can worsen movement symptoms and reduce quality of life. In multiple sclerosis, poor sleep is linked to fatigue, pain, mood disorders and even higher relapse risk, compounding the burden of the disease. Epilepsy and sleep have a two-way relationship, with sleep deprivation known to trigger seizures and seizures themselves disrupting normal sleep cycles.
A body of evidence now positions sleep disturbance as a modifiable risk factor for Alzheimer’s disease and other dementias. By targeting sleep, researchers hope to delay onset and reduce prevalence — an urgent goal given dementia’s growing global toll.
Sleep disorders exacerbate these risks. Obstructive Sleep Apnoea (OSA), which affects up to one in five Australians, fragments sleep and deprives the brain of oxygen, impairing memory and attention. Untreated, it raises risks of stroke, heart disease, and dementia. Insomnia, often co-occurring with anxiety or depression, not only worsens mental health but also heightens dementia risk. Restless legs syndrome and other movement disorders disrupt sleep continuity, further undermining cognitive function.
Practical Steps for Better Sleep
While research expands, there are immediate steps individuals can take to support brain health through better sleep. Key “sleep hygiene” strategies include:
Going to bed and waking at consistent times, including weekends.
Creating a restful environment — quiet, dark, and comfortably cool.
Avoiding alcohol, caffeine, and heavy meals before bed.
Limiting screen exposure in the evening, as blue light suppresses melatonin.
Engaging in daily physical activity to promote natural tiredness.
For persistent problems such as insomnia or suspected OSA, professional support is essential. GPs can provide referrals to sleep clinics, where evidence-based treatments such as CBT-I (Cognitive Behaviour Therapy for Insomnia), continuous positive airway pressure (CPAP) therapy, or mindfulness-based interventions may be recommended. If you live with a neurological condition or care for someone who does, you can also call our TeleNurse line for tailored advice and support – 1800 645 771.
Conclusion
What’s encouraging is that Australia is at the forefront of global sleep research. Alongside major international efforts, our universities and institutes are helping to prove that sleep is not just restorative, but a powerful lever for long-term brain health. From large-scale population studies to cutting-edge dementia prevention trials, this growing body of evidence underlines a simple truth: making sleep a priority is one of the most effective ways to safeguard our minds, today and into the future.
