Sleep and insomnia: understanding and improving sleep

How sleep works

Sleep is not simply switching off; it is an active, organised process. During the night we move through repeating cycles made up of lighter and deeper stages, plus dreaming sleep. Deep sleep helps the body repair and strengthens the immune system, while dreaming sleep supports memory and emotional balance. Two main systems control when we feel sleepy. The first is a natural body clock, roughly tuned to day and night by light, which is why bright light in the morning and darkness at night help set healthy timing. The second is a sleep pressure that builds up the longer we are awake and is discharged by sleeping. Caffeine works partly by blocking this pressure signal, which is why an afternoon coffee can keep you awake at night. Understanding these systems explains why routine and light matter so much.

What insomnia is

Insomnia means finding it hard to sleep even when you have the chance to, and feeling the effects during the day, such as tiredness, poor concentration, irritability or low mood. It might mean lying awake for a long time before falling asleep, waking repeatedly, or waking very early and being unable to drift off again. Almost everyone has the odd bad night, especially when stressed, and that is normal. Insomnia becomes a recognised problem when it happens most nights over a period of weeks or longer and affects daily life. Adults generally need around seven to nine hours of sleep, but the right amount varies, and quality matters as much as quantity. A useful sign of a real problem is not the number of hours alone, but whether poor sleep is regularly leaving you unable to function well.

Why sleep goes wrong

Insomnia usually has more than one cause. Stress, worry and low mood are among the most common, because a busy, anxious mind resists switching off, and lying awake worrying about not sleeping makes it worse. Habits and environment matter too: irregular bedtimes, screens late at night, a bedroom that is too warm, light or noisy, and caffeine, alcohol or heavy meals close to bedtime all disturb sleep. Alcohol may help you drop off but fragments sleep later in the night. Some medical conditions, such as pain, breathing problems, an overactive thyroid or needing to pass urine often, can interrupt sleep, and some medicines have a similar effect. Shift work and jet lag upset the body clock. Because the causes overlap, improving sleep often means tackling several small things at once rather than looking for a single fix.

Proven ways to sleep better

Good sleep habits, sometimes called sleep hygiene, are the foundation. Keep regular sleep and wake times, even at weekends, get natural light in the day, and wind down before bed without bright screens. Keep the bedroom cool, dark and quiet, and use it mainly for sleep. Cut caffeine in the afternoon and evening, avoid alcohol as a sleep aid, and do not lie in bed awake for long — get up, do something calm, and return when sleepy. Regular daytime exercise helps, though not too close to bedtime. For persistent insomnia, the most effective treatment in the UK is not tablets but a talking therapy called cognitive behavioural therapy for insomnia, often shortened to CBT-I, which retrains unhelpful thoughts and habits around sleep and works for most people. It can be accessed through the NHS and some approved apps.

When to see a doctor

Most short-lived sleep problems settle with better habits, but see your GP if insomnia lasts more than a few weeks despite trying self-help, or if poor sleep is seriously affecting your mood, work or safety, for example causing dangerous sleepiness while driving. It is also worth seeking advice if you snore loudly and gasp or stop breathing during sleep, which may suggest sleep apnoea, or if low mood, anxiety, pain or another condition seems to be driving the problem, because treating that often improves sleep. Sleeping tablets are generally used only for a short time and with caution, as they can cause dependence and next-day drowsiness; they are not a long-term answer. Your GP can check for underlying causes, offer or refer you for CBT-I, and help you build a plan that gives lasting, natural improvement in your sleep.