Know your Sleep

Aug 25, 2011 by     1 Comment     Posted under: Healthy Living

Minds and bodies do not operate in the same way throughout the day. A timing mechanism in the brain regulates bodily functions over a 24-hour period. At night, the heart rate falls, blood pressure is lowered and urine ceases to be produced. When the sun rises, the body begins to wake up. One important change that occurs at night time is increased levels of the ‘darkness hormone’ melatonin, which helps us to fall asleep.


The functions of melatonin were until recently a mystery.  This was due to the fact that the gland which secretes melatonin, the pineal gland, a gland about the size of a pea and is shaped like a tiny pine cone (hence its name), was thought to be as irrelevant to human physiology as the appendix. Many scientists believed that this structure, located deep within the brain, was merely the remnant of a primitive sensory system. Recent research, however, has discovered that the pineal gland, through its secretion of Melatonin helps control circadian rhythms (biological cycles that recur over 24 hour intervals). The melatonin signal forms part of the system that regulates the sleep-wake cycle by chemically causing drowsiness and lowering the body temperature.

Sleep, melatonin and light:

Production of melatonin by the pineal gland is inhibited by light and permitted by darkness. For this reason melatonin has been called “the hormone of darkness” and its onset each evening is called the Dim-Light Melatonin Onset (DLMO). The secretion of melatonin is significantly higher at night, although some is produced during the day, and this secretion decreases greatly with age. The pineal functions as a biological clock by increasing its output of melatonin over ten-fold at night.  This increase in secretion begins around dusk, reaches a peak at about 2 A.M., and declines to low levels by sunrise.  With aging, the peak in melatonin levels occurs about one hour later than normal, and the maximum peak of melatonin is only one-half the level of young adults. Infants’ melatonin levels become regular in about the third month after birth, with the highest levels measured between midnight and 08:00 (8 AM).

Since it is principally blue light that suppresses melatonin, wearing glasses that block blue light in the hours before bedtime may avoid melatonin loss. Use of blue-blocking goggles the last hours before bedtime has also been advised for people who need to adjust to an earlier bedtime, as melatonin promotes sleepiness. For totally blind individuals, with no subconscious feedback to the pineal gland, there may be periods of severe insomnia, or they may fall asleep at unusual times.

 Did you Know?

A Regulating Switch:

Melatonin acts as a regulating switch, pushing the body clock forwards or backwards. Interestingly, administration of melatonin at the right time and in the right dosage can reduce the feeling of malaise which occurs when a persons normal pattern of light and dark is interrupted by, for example, shift work or travelling rapidly several time zones (jet lag). Melatonin may also be associated with winter depression, the lowering of some people’s mental state caused by the reduced amount of daylight in winter.

The Sleepy Teen:

Sleep patterns go crazy during your teenage years. Many teens have the energy to play computer games until late at night but can’t find the energy to get out of bed in time for school. This may be more than just laziness and bad behaviour. One thing is for certain – sleep is crucial for teenagers because it is while they are snoozing that they release hormones that is essential for their growth. They need more sleep than both children and adults, but they get less than either. Everything in their lives works against them in terms of getting the amount of sleep they actually need. For most adolescents, insufficient sleep results from the interaction between intrinsic factors such as puberty and extrinsic factors such as school start times.

New Research has found that the hormonal upheaval of puberty could be pushing the melatonin release back, in which case teenagers are being kept awake by their bodies – they simply can’t help their peculiar sleeping behaviour. Most adults start to produce melatonin at about 10pm. When teenagers were studied in a sleep laboratory, researchers discovered that they only began to produce the hormone at 1am.This means they are not sleepy in the evening, and have energy deep into the night. However, they are tired in the morning, and are less alert. This is one reason that teens are likely to be going to bed later and hoping to wake up later than everyone else in the family.

So let sleeping teenagers lie!

Whether late nights are caused by biology or behaviour makes no difference – many teenagers are sleep deprived. Lack of sleep can lead to moodiness, impulsivity and depression.

In America, some schools have delayed the start of their classes to 9 or 10 am to give their teenagers some extra time in bed. Such schools have noticed that students are now performing better on tests, there is a lower absentee rate and students are more attentive and less aggressive.

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1 Comment + Add Comment

  • This is an informative read and I would suggest Zehra to include working adults with teens to start working after 10am… I would love to read other news topics from you in the future..

    Bilal Mehdi

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