Sleep is one of our most basic needs. We all know that good sleep is needed after the activities of the day to feel refreshed, restored and able to face the next day’s challenges satisfactorily. Other important functions occur during sleep including processing of information (“sleeping on the problem”) and consolidating memory. However exactly how the brain accomplishes this during sleep remains unclear.
The brain is certainly active during sleep, as is demonstrated by the electrical signals (the electroencephalograph, or EEG) that are generated while asleep. These signals are very different to those of wakefulness, reflecting the different nature of this activity as rest and information processing take place. During healthy sleep blood pressure, heart rate, breathing and body temperature all decrease compared to wakefulness.
Inadequate sleep can result from insufficient duration (often because insufficient time in bed has been allowed for), inappropriate timing (as can occur with shift work or jet lag) or inadequate quality (as occurs with sleep disorders). The consequences of inadequate sleep include: tiredness and lethargy; impaired memory and concentration; disturbed ability to perform tasks requiring attention, vigilance and complex thinking; and mood changes including increased irritability.
Healthy Sleep And Sleep Disorders