Introduction: What is 'Sleep'?

A naturally recurring state of body and mind which typically recurs for several hours every night where:

  • The nervous system is relatively inactive
  • Sensory activity decreases
  • Eyes are closed 
  • Muscles are relaxed 
  • Consciousness is suspended
  • Interaction with surroundings is reduced

Why do we need sleep?

  • To surviveĀ 
  • To keep the nervous system functioning
  • To rest and repair
  • To learn
  • To grow
  • To maintain optimal emotional and social functioning
  • To help encode memories and improve learning
  • To minimise the effects of sleep deprivation

Restful and adequate sleep provides the foundation for optimal occupational performance, participation and engagement in daily life



The physiology of sleep

Nerve-signalling chemicals in the body, called neuro-transmitters, control whether we are awake or asleep

A chemical called adenosine builds up in the blood when we are awake and causes drowsiness. It breaks down when we are asleep.

When we fall asleep, the neurons at the base of the brain switch off the signals that keep us awake.

Neurons in the brain stem (which connects the brain and spinal cord) produce chemicals such as serotonin and norepinephrine that keep certain areas of the brain active while we are asleep.

Salford Royal NHS Trust Resource Menu