Can't Sleep? What's Keeping You Awake (and What Helps)
Most people have nights where sleep simply will not come. For some, it happens occasionally — around an exam, a job change, a difficult season. For others, lying awake becomes a pattern that starts to affect energy, mood, and daily functioning. Either way, understanding why sleep is disrupted is the first step toward doing something about it.
This article explains the most common reasons people can't sleep, what you can do tonight, and when persistent sleeplessness deserves clinical attention.
Key takeaways
- The most common reason people can't sleep is a state called hyperarousal — a wired, alert nervous system that won't settle at bedtime.
- Habits, environment, and an irregular body clock all play important supporting roles.
- Short-term practical steps — consistent wake times, wind-down routines, limiting time in bed — are grounded in the same evidence base as formal insomnia treatment.
- Cognitive behavioural therapy for insomnia (CBT-I) is the gold-standard, first-line approach recommended by international sleep medicine bodies (AASM, 2021; ESRS, 2023).
- If you've struggled to sleep for three or more nights per week for longer than three months, that pattern is worth discussing with a clinician.
Why can't I sleep? The most common reasons
Is your mind and body stuck in "alert" mode?
The most well-studied driver of insomnia is hyperarousal: a state in which the nervous system remains on heightened alert even when you're trying to rest. Stress, anxiety, unresolved worries, and even the habit of watching the clock all feed this state. The brain starts to treat the bed as a place of wakefulness and frustration rather than rest — a pattern that can persist long after the original stressor has passed.
This isn't a character flaw or a failure of willpower. It is a learned physiological response, and it can be unlearned with the right approach.
Are your sleep habits working against you?
Irregular sleep and wake times, long or late naps, spending extended time in bed while awake, and using the bedroom for screens, work, or worry all make it harder for the brain to associate bed with sleep. These patterns are sometimes called "poor sleep hygiene," though that term undersells how powerful they can be in perpetuating sleeplessness.
Could your body clock be out of sync?
The body's internal clock — the circadian rhythm — governs when you feel alert and when you feel drowsy. Shift work, frequent travel, prolonged evening screen time, and inconsistent schedules can shift this clock in ways that make falling asleep at a conventional time genuinely difficult, not just frustrating.
Light is the primary signal your clock uses to set itself. Morning light exposure and reduced bright light in the two hours before bed are two of the most effective (and underused) tools for resetting a drifting schedule.
Could an underlying condition be involved?
Sleep difficulties are sometimes a symptom rather than a standalone problem. Mood conditions such as anxiety and depression are closely linked with insomnia, as are chronic pain, certain thyroid conditions, and sleep-specific disorders such as restless legs syndrome or sleep apnoea. If your sleeplessness comes with loud snoring, gasping, leg discomfort, or persistent low mood, these are worth raising with a clinician.
Practical steps you can take now
These steps are drawn from CBT-I — the evidence-based first-line approach for insomnia. You don't need a formal programme to start applying them.
Set a consistent wake time — and keep it
The single most powerful sleep lever most people have is their wake time. Waking at the same time every day (including weekends) anchors your body clock and builds sleep pressure, making it easier to fall and stay asleep at night. Choose a time you can sustain and protect it.
Get out of bed if you're not sleeping
If you've been lying awake for what feels like 20 minutes or more, get up. Go to another room, do something quiet and low-stimulus (reading a physical book, gentle stretching), and return to bed only when you feel genuinely sleepy. This is called stimulus control — it re-trains the association between bed and sleep. It feels counterintuitive, but it is one of the most consistently effective CBT-I techniques.
Create a wind-down window
Your nervous system needs time to transition from alert to calm. A 30–60 minute wind-down before bed — away from bright screens, news, work emails, and anything stimulating — gives your body the signal that sleep is approaching. Low lighting, a consistent routine, and relaxing activities help anchor this shift.
Limit time in bed to time you're actually sleeping
It may feel logical to go to bed earlier when you're not sleeping well, but spending extra hours in bed while awake actually fragments and lightens sleep. A structured reduction in time in bed (sleep restriction) is one of the core CBT-I techniques and is best done with clinical support, but the principle — keeping your time in bed closer to your actual sleep time — is worth understanding.
Get morning light
Within an hour of waking, spending time in natural daylight (even through a window) helps synchronise your body clock and can meaningfully improve evening sleepiness. This is especially relevant in winter months or for those who work indoors throughout the day.
When does "can't sleep" become chronic insomnia?
Occasional sleeplessness is a normal human experience. Chronic insomnia is generally defined as difficulty falling asleep, staying asleep, or waking too early — occurring at least three nights per week, for at least three months, and causing meaningful daytime difficulty (fatigue, poor concentration, mood changes, difficulty functioning).
If that pattern sounds familiar, you are not alone — and the good news is that it responds well to the right approach. CBT-I has a strong evidence base and produces durable results. Where appropriate, a physician may also consider other options as part of a broader plan.
A free Sleep Pattern Assessment is a useful starting point. It takes a few minutes, gives you a structured picture of what your sleep looks like, and helps a clinician understand your situation before any consultation. It is an assessment tool — not a diagnosis.
Slumbr does not provide emergency care. If you are in crisis or experiencing thoughts of self-harm, please contact SADAG on 0800 567 567 (24/7 free) or go to your nearest emergency unit.
Frequently asked questions
Why do I feel exhausted but still can't sleep? This "tired but wired" state is a hallmark of hyperarousal. Your body is fatigued, but your nervous system is still running in an alert mode that overrides the sleep drive. It is one of the most common presentations in chronic insomnia and responds well to CBT-I techniques that specifically target arousal.
Does screen time before bed actually make a difference? The evidence is reasonably consistent: bright light from screens in the hour or two before bed can delay the release of melatonin (the hormone that signals night to your body clock) and increase alertness. The strength of the effect varies between people, but reducing screen brightness and avoiding stimulating content before bed is a low-risk step worth trying.
Can I use sleep supplements while trying to fix my sleep? Some supplements are used to support healthy sleep — but they work best alongside behavioural changes, not instead of them. If you're considering a supplement, it's worth discussing with a clinician to ensure it's appropriate for your situation. Over-reliance on any aid — supplement or otherwise — can sometimes reinforce the anxiety around sleep rather than resolve it.
Should I see a doctor if I can't sleep? If your sleep difficulties have persisted for more than a few weeks, are affecting your daily life, or come with other symptoms (mood changes, breathing concerns, leg discomfort), yes — a structured clinical assessment is worthwhile. Online consultations make this accessible without needing to travel or wait for a GP appointment.
Ready to understand your sleep?
A free Sleep Pattern Assessment takes a few minutes and gives you a clear picture of what your sleep looks like — and what might be driving the difficulty. It's a starting point, not a diagnosis.
Take the free Sleep Pattern Assessment →
If you've been struggling for a while and want to speak with a clinician directly, an online consultation is available at a time that suits you.
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