Good quality sleep is vital to the health of the body and mind. Adults need 7 to 8 hours of sleep at night while adolescence needs around 9 to 10. We are just beginning to understand through Neuroscience why we need sleep. Sleep deprivation or poor-quality sleep can lead to disorders. It can be as simple as irritability, fatigue, and loss of concentration in the short-term. Long-Term sleep deprivation can lead to immune system related disorders (like inflammation, autoimmune diseases), psychological disorders (like anxiety, depression, hallucination), hormonal imbalance, diabetes and even cardiovascular diseases (like high blood pressure).

The full functioning of sleep is yet to be uncovered by Neuroscience. So far it is known that sleep is important to maintain healthy brain functions and the nervous system. Contrary to the normal perception, your brain (to a large extent) and body (to some extent) stay active while you are asleep. Sleep plays a key housekeeping role to removes toxins in your brain and to consolidate memory and experiences.

During our work hours, our cells are busy using up our energy sources which finally are broken down into various waste by-products (including a chemical called Adenosine). Such waste needs to be cleared up. During our sleep, a cleanup mechanism called “Glymphatic system” removes this built-up waste. The cerebrospinal fluid flushes away these toxic by-products accumulated in the cells. Lymphatic vessels that serve as pathways for immune cells have been recently discovered in the brain. They play a big role in clearing these toxins.

Also, sleep is an essential ingredient of memory consolidation and embedding past experiences of the day in our long-term memory. This includes emotional memories (e.g. memories with strong emotional content like fear) or procedural memories (learning through repetition like riding a bike) and declarative memories (learning through a cognitive process that takes conscious record of your experiences, e.g. what you had for dinner). We plan to cover different types of memories and consolidation in a future post.

There are several other physiological processes that occur in the brain and nervous system during sleep that are important for bodily functions, although its exact role from a neuroscience perspective is still being uncovered.

Sleep deficiency is known to carry the following risks:

• Reduced or even loss of focus, concentration, memory and decision making
• Hormonal imbalance – increased in the level of Cortisol
• Imbalance of Neurotransmitters – Dopamine, Serotonin and Norepinephrine – which are commonly associated with anxiety, depression, and irritability
• Increased risk of cardiovascular disease
• Immune system imbalance – resulting in frequent complaints of flu, colds, and even to the extent of autoimmune diseases and cancer
• Type-2 Diabetes
• Research also suggests that sleep disturbances may cause Fibromyalgia or exacerbate the symptoms. Fibromyalgia syndrome (FMS) is a chronic disorder marked by whole body aches and pains and extreme daytime fatigue. 

It is not just important how many hours you sleep, but also how good your sleep quality is, and how uninterrupted it is. The best way to determine whether you get enough sleep is by asking yourself two questions (i) do you feel refreshed when you wake up in the morning, and (ii) do you feel alert and active throughout the day? If the answer is NO, you may be experiencing some kind of sleep disorder that requires your attention. It is important to recognize such a situation early and act on it before it creates havoc in your life.

Stay tuned for our next few posts. We plan to cover:
• brain waves and different stages of sleep
• sleep hygiene that one can follow to improve the sleep quality
• how Yogasana and Pranayama practice improve sleep quality and help those who are suffering from sleep disorders

Also, if you have not done so far, read our most popular post on neuroscientific explanation on “why Yoga inversions are so effective for mental health”.