Are you aware that we sleep approximately a third of our lives? Is sleep mandatory? Can we practise sleeping less? Why is sleep so important? What are the functions of sleep?
Hunger and sleep are the protective mechanisms regulated by internal drives of our body. Our body can’t force us to eat when hungry, but can put us to sleep when we are tired. Sleep is needed for the overall well- being of our body. Sleep enables our body to restore, rejuvenate, repair tissues, and synthesize hormones. Sleep is also considered as a basic need of the body, just like nutrition and exercise.
Two main processes that monitor sleep are: circadian rhythms and sleep drive. Circadian rhythms are controlled by a biological clock located in the brain. The biological clock in the body responds to the light cues, ramping up the melatonin production in the body at night and switching it off when it senses light.
Sleep drive of the body can be decreased and can throw off our night’s sleep with a nap of more than 30 minutes in a day. Adenosine is produced as a by-product by the neurons as a result of cellular activities in our body. During day time, adenosine accumulation during wakefulness may trigger our sleep drive. During sleep, adenosine clearance happens from the system, and, as a result, we feel fresh and more alert when we wake up after a good night of sleep.
Science behind sleep
There are two types of sleep in a sleep cycle: REM and non-REM.
Non-rapid eye movement sleep or in short, REM is the first part of the sleep cycle and is composed of 4 stages. The initial phase is marked between falling asleep and being awake. Second is the light sleep. In this stage, heart rate and breathing regulate, and body temperature drops. The third and fourth stages are marked as deep sleep. Recent studies prove that non-REM sleep is essential for learning and memory. This is considered the restorative phase of sleep.
As we cycle into rapid eye movement, in short REM, eyes move rapidly behind closed lids. An increased breath rate marks it. Dreams occur during this phase of sleep.
The cycle repeats itself throughout the sleep while we are asleep. Ideally, good sleep has three or five of such cycles being covered in each night. With each cycle we advance, less time is spent in deeper stages of sleep, third and fourth stage of non-REM, and more in REM sleep.
Benefits of good quality and quantity of sleep:
Improved alertness: Sleep is needed for brain plasticity. The ability of the brain to learn and adapt to the inputs and newer challenges can be linked with sleep. It allows our brain to clean up by removing waste products and organize bits and pieces of information to memory to pull them up later. It improves mental awareness to regain focus and stimulates creativity.
Healthier heart: It decreases blood pressure. Heart and blood vessels rest up to some extent during sleep which is otherwise not possible during a busy day.
Increased Energy: The energy levels after a healthy sleep are usually high, increasing sports achievements.
Ward off infections: Sleep deprivation can weaken our immune system and the germ fighting capacity of our body.
Obesity: Sleep deprivation messes up with the hunger controlling hormones and tempts the body for unhealthy foods. Staying up for long nights might lead to obesity with time.
Type 2 diabetes is less likely: During the more in-depth phase of sleep, the amount of glucose drops and allows our body to regulate blood sugar levels. A good amount of sleep can delay the onset of type 2 diabetes.
How much sleep is ideal?
Sleep requirements vary from person to person owing to age, lifestyle, and health. However, the National Institute of Health suggests the following sleep recommendations following the age group.
- Newborns need 16- 18 hours of slumber for optimal development of the body.
- Preschool-aged children need 11 to 12 hours of sleep.
- School-aged children need at least 10 hours.
- Teens need 9 to 10 hours of sleep.
- Adults 18+ and elderly need 9 to 10 hours of sleep.
The Bottom Line: To sum up, everyday’s sleep needs can be met by adopting proper sleep hygiene. Accumulating the hours of sleep deprivation in a week and then sleeping during weekends to make up the sleep debt is not ideal in the long run. Seven to eight hours of quality slumber each night is essential for reaping the peak health benefits associated with it.