Dr. Sunita Kumari
Every year International Sleep Day is observed on the third Friday of Marchand was started in 2008 by the Committee World Sleep Society, founded by World Association of Sleep Medicine (WASM) and World Sleep Federation (WSF).The slogan of “World Sleep Day” is “Better Sleep, Better Life, Better Planet”. Every year on World Sleep Day, scientists put an effort to make the public aware regarding the value of having a restful, sound, and timely sleep through different yearly themes. In the year 2024, World Sleep Day is being observed on March 15 and the theme is “Sleep Equity for Global Health”.
Sleep is very important part of our daily routine. We spend about one-third of our life-time sleeping.Restful sleep provides the foundation for mental and physical well-being. Millions of people across the world suffer from some form of insomnia (lack of sleep), and many of them even meet the diagnostic criteria of sleep disorders, resulting in lack of mental alertness, fatigue, and weakened physical and mental health that also contributes to both minor and major injury accidents.The present article isdedicatedtopromote sleep health across the readers and also to raise awareness about the ill-effects of sleep deficiency. Sleep health is multi-dimensional pattern of sleep-wakefulness, adapted to the individual, social and environmental demands that promote physical and mental well-being. Restful sleep means, we drift off easily once we turn off the lights and sleep soundly through the night. If we have to get up to go to the washroom during the night, we are easily able to get back to sleep. If upon awakening in the morning we feel alert, energetic, and vibrant this indicates that we have had an adequate and restful sleep. In contrast if we feel unenthusiastic, tired, grumpy and groggy in the morning, it indicates that we have not had a restful sleep in the night.
How much sleep do we need?
The requirement of sleep and sleep patterns change with increasing age, but this varies significantly across the individuals of same age as well. There is no “magic number of sleep hours” that works for every one of the same age. Infants and small children usually sleep for about 16 to 18 hours a day, which helps boost their growth and development (especially of the brain). Older children require about 9 to 10 hours of sleep every night. Most of the adults require 7 to 9 hours of sleep per night, but after the age of 60, people tend to have shorter and lighter sleep interrupted by multiple awakenings.
Sleep deprivation (sleep deficiency) is deficit in the quantity or quality of sleep obtained versus the amount needed for optimum health, performance and well-being. Chronically sleep deprived people are more likely to have obesity, hypertension, depression, anxiety, constipation, bloating, weakened immunity, infections, diabetes, stroke, certain types of cancer and cardiovascular disease than those who get enough sleep. Sleep disturbances are more common among individuals with age-related neurological diseases like Alzheimer’s disease and Parkinson’s disease.
How the need for sleep is regulated?
Our body’s master clock controls a number of functions in the body including release of hormones, metabolism, body temperature and the circadian rhythm. It also controls the timings of our sleep and makes us sleep at night and wake in the morning. Sleep-wake homeostasis also determines need for sleep. This homeostatic sleep drive regulates sleep intensity and also reminds our body to sleep at a certain time. After prolonged sleep deprivation this sleep drive progressively gets stronger each hour and makes us sleep longer and more deeply. Factors that influence our sleep-wake needs, includes medical conditions, medications, stress, sleep environment, and even what we eat and drink. Exposure to light has the greatest influence. It is difficult for a person to fall asleep if he is exposed to light at night. This is the reason that night shift workers often face trouble falling asleep, and also have trouble in concentrating at their work while awake. This is because of disruption of their sleep-wake cycle and natural circadian rhythm. Same thing happens in case of jet lag. When someone flies to a different time zone, creating a mismatch between the actual clock and the internal biological clock. Melatonin, a hormone released by the pineal gland helps us feel sleepy once the lights go off. The peaks and downfalls of melatonin are important for maintaining the body’s circadian rhythm according to the natural day and night cycle.
What happens in the brain and body during sleep?
Sleep is not just a time when our body and brain shut down, but has important biological purpose. Sleep has a housekeeping role and removes toxins from the brain (built up during awake state) and helps maintain internal environment of the body as a whole. During sleep, a balance is attained among the hormones and neurotransmitters, neural myelination occurs and new pathways or neuronal connections are formed that helps in memory consolidation (short term memory is converted in to long term memory). Also, during sleep our body produces certain hormones that help repair cells and tissues and fight off illness. Getting sufficient sleep helps us think more clearly and respond more quickly. Sleep helps each and every cell of our body to function physiologically in a way they are supposed to.
Night time sleep consists of multiple sleep cycles and transitions between lighter and deep sleep stages. There are two basic types of sleep, Rapid Eye Movement (REM) sleep and Non-Rapid Eye Movement (NREM) sleep which again has three different stages. During each typical night, we cycle through all stages ofsleep several times, and the length of each stage varies throughout the night, with longer periods of deep (NREM) sleep earlier towards the first half and longer periods of lighter (REM) sleep as the morning approaches. These sleep cycles may vary from person to person and from night to night. Sleep stages allow the brain to recuperate andthe brain gets ready for the next day.Improved sleephygiene allowsa healthy transition through all sleep stages. REM sleep starts about 90 minutes after we fall asleep. Our eyes undergo rapidside to side movements behind the closed eyelids. Breathing becomes irregular and fast. There is increase in blood pressure and heart rate to near waking levels. Dreaming occurs in this stage and also our limb muscles temporarily get paralysed so that we are not able to act out our dreams. Acting out of dreams can be dangerous.
NREM Sleep stage 1 is the transition phase from wakefulness to sleep. It is a short period of light sleep. NREM stage 2 sleep is a period of light sleep before we enter in to deeper sleep. We spend more of our repeated sleep cycles in stage 2 of sleep than in other stages.
NREM sleep stage 3 is the most restful sleep period that makes us feel refreshed and rejuvenated when we wake up in the morning. We pass through longer periods of NREM stage 3 sleep cyclesduring the first half of the night. It is difficult to awaken someone up cycling through this stage of deep sleep. If they do wake up, they will probably have “sleep inertia or mental fog”, aconfusion like stateand it may last for about halfan hour.
Preparing for restful sleep
It takes just a small shift in your attention and behaviour to have a sound, restful sleep each night. Not gaining restful sleep is usually a result of poor habits. People having hard time getting to sleep, may try following tips:
Aim for a nightly seven to nine hours of sound slumber without the aid of medications. Hours of sleep before midnight are generally the most rejuvenating. Therefore, if we are sleeping 8 hours between 10 pm to 6 am, we will feel more rested than if we slept eight hours between midnight and 8 am.
Maintain a regular sleep schedule. Our bodies and minds love patterns and routines, so if we get used to sleeping and waking up at certain times, we are likely to continue it out of habit. Aim to be in your bed with the lights out between 9:30 pm and 10:30 pm. Get at least 30 minutes of natural sunlight each day. Day light helps regulate sleep patterns.
Eat a relatively light dinner so that your sleep is not disturbed by indigestion or the need to urinate repeatedly. Also, dinner should be taken no later than 8 pm so you do not go to bed on a full stomach. Take a leisurely stroll after dinner. Avoid caffeine, alcohol and nicotine.
Remove sleep distractions from your bed room such as TV, noises, bright lights. With the emergence of technology our daily routines are out of synch with nature. To the extent possible, minimize exciting, aggravating, or mentally intensive activities after 8:30 pm.
Don’t ruminate your thoughts once you are in your bed, just close your eyes, focus on your body and simply watch your slow easy breathing until you fall asleep.
Spirituality, Yoga and Music Therapy are of great help. Read inspirational or spiritual literature for a few minutes before bed. Specific restorative yoga poses soothe, relieve tension and stress and facilitate sound sleep. Listening to soothing music also helps with sleep. Music is an accessible, effective and low-cost treatment for sleep deficiency.
Core message
Sleep is the foundation of health and has a repairing effect over each and every cell of the body. Although many mysteries regarding the relation of sleep with various health problems are yet to be solved but till now it is clear that transition through all the different stages of sleep is important for the mind and body to accomplish the detoxifying homeostatic tasks during sleep. Therefore, follow the above-mentioned sleep hygiene strategies every night and have a sound sleep.
(The author is Assistant Professor, Department of Physiology, AIIMS, Jammu).
