The Secrets of Sleep

If there is one thing you can never get enough of, its sleep. Perhaps everyone of us has definitely experienced a lot of downtime at some point of time or the other with sleep. When you get very little sleep, you feel tired and groggy.When you oversleep, you still feel tired and groggy. Everyone has an optimum amount of sleep time, usually between 6 - 8 hours. Anymore or less tends to make them irritable. A little known secret about sleep is the 'manner' in which it takes place and the various cycles that occur while you are at it.

Communications across neural networks in the brain occur through electric charges.Hence, the brain constantly emits brain waves which occur due to synchronous and coherent electric activity in large groups of neurons. By the means of an EEG (Electroencephalograph) scientists have studied brain activity that takes place during sleep and come to the following conclusions.
Depending on the activity, the brain emits waves of different frequencies.


Sleep takes place in 5 stages. Each stage exhibits a different wave frequency and performs different functions.
Awake - This is the stage you are in just before you fall asleep. This is characterized by Beta brain waves. Respiration, blood pressure and heart beat are normal.
Stage 1 - Your brain exhibits Alpha waves during this stage. You lose awareness, Respiration, heart rate, B.P. drops. This is when you experience those few moments between sleep and awake.
Stage 2 - There are sudden bursts of brain activity known as sleep spindles and K-complexes(transient slow waves). When woken up, you wake with a 'jump' and feel as if you were awake all the time.
Stage 3 and 4 - This is Deep Sleep. Theta Waves and Delta waves are prevalent during this phase. Blood Pressure, respiration and heart rate drop. Blood vessels dilate and blood stored in organs throughout the day travel to your muscles. The body's immune system is activated. You feel groggy and weak when you are woken up at this time.
REM - This is called the Rapid Eye Moment stage. Most people dream during this stage.Brain activity increases.The brain stops the release of neurotransmitters and the body is temporarily paralyzed. Your eyes move rapidly. The learning and memory region of the brain is stimulated during this stage. About 20% of adult sleep time is in this stage. In babies, it is more than 50% of their 16 hour sleep time.

Study of the Graph
- The graph clearly shows that sleep takes place in cycles. Each cycle lasts about 90 to 110 minutes.
- As the cycles progress, the period of REM stage increases and period Deep Sleep decreases.
- Stage 4 Sleep is terminated at approximately 5 hours and 15 minutes after falling asleep. Since one of the primary functions if sleep is wear and tear, it is safe to skip sleep after this point without greatly damaging your health.
- Test subjects who were deprived of REM stage sleep faces memory problems and could not properly recollect the experiences of the previous day. Make sure you at least get 6 hours of sleep in a day.
- A person is most wakeable during REM stage of sleep as brain activity is the highest.Thus the best time to wake up a person is - within 45 minutes of falling asleep - 3 hours of falling asleep - 4 and a half hours - 6 hours. Clearly after the first cycle, which is mid way at around 1 and a half hours, you can easily wake up progressively 90 minutes (or one and a half hours later)

The cause of Mid-day and Back-from-work drowsiness
The Human body temperature fluctuates through 38 degrees celcius and 36 degrees celcius and remains average at around 37 degrees. Whenever body temperature rises, you feel awake and there is more brain activity. A temperature drop makes the body more lazy and the body tries to enter stage 1 sleep. This explains why there is usually drowsiness during noon time and most people are active during the evenings. For the average person, body temperature starts increasing after 4AM in the morning. However, if you usually wake up at 10 AM, then your body temperature increases from this point. Keep in mind there is a sudden depression at around 6 - 7 hours of waking up. Such a depression occurs commonly whenever there is a change of work. For example, if you were working in the field for 8 hours, after your work is done, you tend to feel drowsy. This is because while you were working, you body temperature was high. But as you finish, it starts decreasing and you tend to feel sleepy. Some call it back from work drowsiness.
To combat this, instead of hitting the couch and switching on the TV, try going for a walk or playing with the kids. This will increase your body temperature and within 30 minutes, you'll feel energetic and rejuvenated again. Exercise helps to postpone this depression and thus helps you sleep better.

The key to taking an efficient 'Nap'
You may often take naps when you are feeling tired. Usually mid-afternoon. Taking naps is definitely an effective way to quickly recuperate your energy, but it must be doe in the right way. Look bak at the sleep cycle. as you can clearly see,
if you exceed 45 minutes of sleep, you will enter deep sleep. If you are woken up after this, you will feel groggy and want to go back to sleep. If you want to feel refreshened when you wake up. make sure nap time doesn't exceed 45 minutes or the benefit of the nap will be lost.

The best kept Secret about the Sleep clock
Melatonin is a hormone synthesized by the pineal gland which is responsible for sleep and restoring physical energy. High melatonin levels in blood promote laziness. Melatonin secretion increases in darkness or low light environments and decreases when the body is exposed to sunlight. This is because of the sleep 'clock' that regulates the body's circadian rhythm (physiology). The 'clock' called the Superchiasmatic Nucleus (SCN) is a pair of pinhead sized structures containing 20,000 neurons located in the hypothalamus. Light that reaches the photoreceptors in the retina of the eyes create signals that travel along the optic nerve to the SCN. When the SCN is stimulated, it cuts off melatonin production. Thus, whenever you are feeling sleepy, try taking a walk in the sun or a brightly lit area.

The best practice to beat the urge to go back to sleep on waking up is to stare at the sun immediately within 30 seconds of waking up. This will immediately reduce melatonin level in your blood and help you get over wake-up drowsiness.


*Special Disclaimer
As this article in particular contains a lot of medical lingo, I hereby state that I take no responsibility for any discrepancy that may have creeped into the information I have provided. I've verified it to the best of my abilities. If you however find any bit to be incorrect, kindly notify me.