Sleep: Myths and Facts

Dr. Sofiya Salim Malik, Senior Consultant Pulmonologist, SUT Hospital, Pattom

Sleep is the condition of reduced state of responsiveness which is rapidly reversible with reduced motor activity and metabolism. This phenomenon is found in different ways in every living being. It is assumed that sleep plays an important role in the theory of evolution. Humans spend about one-third of their average lifespan on sleep that is 8 hours of sleep at night.

1. Importance of sleep

i. Restoration
• Repair and revitalisation.
• Feel refreshed
• Growth hormone secretion reaches peak and leads to muscle growth and cell regeneration.

ii. Energy conservation
• Clearance of substances like adenine and other neurogenic waste.

iii. Memory consolidation
• Helps in learning and enhances memory – NREM.

2. Elements of sleep

Deep sleep – NREM (Non-Rapid Eye Movement) associated with respiratory and cardiovascular system.
REM Sleep – Irregularities in heartbeat, Blood pressure, shortness of breath. Different stages of sleep are related to the functioning of the brain. Newborns spend most of their time on the REM Sleep component.

Sleep Deprivation

• Duration – Quantity
• Depth – Quality
Poor sleep duration adversely affect our day time alertness and performance. When a normal person experiences sleep loss the body tries to enhance the duration and depth of sleep to compensate the situation. Sometimes the depth of sleep increases without changing the duration. Sleep duration alone cannot be considered as a standard measurement of quality sleep.

Causes of Sleep Deprivation
• Work demands
• Social and family responsibilities
• Medical conditions
• Sleep disorders
Sleep insufficiency results when sleep is not adequate in quality and quantity to support alertness, performance and health.

1. Acute sleep deprivation

• No sleep for 1 – 2 days.

2. Chronic sleep deprivation.

• Individual sleep less than the amount needed for normal functioning.
• This condition is caused by not being able to sleep. If the situation is favourable, they will fall asleep.

Neither of these is a condition called insomnia. In both cases duration of sleep is low. People with insomnia may not be able to sleep even if they have a favourable environment and are extremely tired.

How much sleep does the average person need?

1. How long can a person sleep if they are allowed to sleep without any disturbance, can be considered as quality sleep. Another way is that how much sleep can bring maximum energy and freshness to a person. Find out if you are refreshed, considering the ability to get up in the morning and engage in tedious work efficiently and beautifully.
2. The duration of sleep depends on the age and living conditions of an individual.
3. The average sleeping hours of a person is 6 – 8 hours.
4. For some people, 6 hours or less sleep may be enough to keep them refreshed.
5. Some people need more than 10 hours of sleep a night.
AAMS (American Academy of Sleep Medicine) recommends 7 hours sleep/night promotes optimum health. Decreased sleep duration is a major problem we are facing now. Studies in 20 countries have shown that children lose 0.75mts / yr of sleep. This was seen in boys who were high school students. More than 6-9 hours of sleep indicates mental stress.

Quality sleep

Even if you sleep for more than eight hours, you may experience insufficient sleep, possibly due to disturbed sleep or interruptions. Quality is determined by how arousals. 5 arousals / hr Sleep can lead to sleepiness during day time even after a single night. We do not even know about this because this awakening is momentary. We will continue in whatever stage of sleep we were in.