What the brain does while you sleep
During deep sleep the brain consolidates what you learned during the day and clears metabolic waste that builds up while you are awake. During REM sleep it processes emotions and links new information with old. Cutting sleep short interrupts all of this.
Sleep and mood
People who sleep poorly are more irritable, more anxious and more reactive to stress. Insomnia and depression are closely connected: poor sleep can be an early sign of depression, and it can also make depression and anxiety harder to treat. Treating sleep problems often improves mood as well.
Sleep, attention and memory
- Even one night of poor sleep slows reaction time and weakens attention
- Learning and memory suffer when sleep is short or broken
- Decision-making and judgement become poorer, which matters at work and on the road
- Children and teenagers who sleep less often struggle with behaviour and school performance
Signs your sleep may be affecting your mental health
- Difficulty falling asleep or staying asleep for more than a few weeks
- Feeling tired or low even after enough hours in bed
- Racing thoughts or worry at bedtime
- Growing dependence on caffeine in the day or sleeping pills at night
What helps
Regular sleep and wake times, a calm wind-down routine, daylight exposure in the morning and limiting screens before bed all help. For persistent insomnia, cognitive behavioural therapy for insomnia (CBT-i) is the recommended first-line treatment and works better in the long term than sleeping pills.
If poor sleep and low mood have lasted more than a few weeks, please consult a doctor. Sleep and mental health are best treated together.
