Sleep appears necessary for our nervous systems to work
properly. Too little sleep leaves us drowsy and unable to
concentrate the next day. It also leads to impaired memory and
physical performance and reduced ability to carry out maths
calculations. If sleep deprivation continues, hallucinations and
mood swings may develop. Some experts believe sleep gives
neurons used while we are awake a chance to shut down and repair
themselves. Without sleep, neurons may become so depleted in
energy or so polluted with by-products of normal cellular
activities that they begin to malfunction. Sleep also may give
the brain a chance to exercise important neuronal connections
that might otherwise deteriorate from lack of activity. Deep
sleep coincides with the release of growth hormone in children
and young adults. Many of the body’s cells also show increased
production and reduced breakdown of proteins during deep sleep.
Since proteins are the building blocks needed for cell growth
and for repair of damage from factors like