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Writer's pictureDr Suresh K R Kumar

How much sleep do you need?

Updated: Apr 25, 2021


Are you getting enough sleep? How much sleep do we need? Do older people need less sleep?

These are the questions which most of us are concerned with, especially in the current times when our sleep is disturbed due to the social media and the binge watching most of us do in the bed.

We are all familiar with the concept of “night owls’ and “morning larks”. The night owls feel energetic and are full of life till very late in the night while the morning larks are at their best in the mornings. Any change in their pattern puts them in an unhappy circumstance and their productivity suffers. Good sleeping habits mean that we are productive and healthy. At the same time bad sleeping habits affects not only our moods and productivity but has a great impact on our immunity.

How much sleep do we need to survive and be healthy? Before we answer this question, it is important to understand why sleep is important for our well-being.

All of us know how important sleep is. When we don’t have a good night’s sleep the effect is very clear on the next day – we find it extremely difficult to get up and even if we do, we feel tired and listless in the very first hour of the morning. And when have a good sleep, we wake up without any effort and feel energized throughout the day.

Sleep is the nature’s way of shutting down majority of the functions of the body, so that it can undertake repair and maintenance. It’s more like you taking your vehicle to the garage after a specific period for maintenance. While at the garage, your vehicle will be lubricated, oils changed, plugs cleaned, filters changed, etc. When you drive your vehicle after maintenance you can feel the effect – the vehicle will be moving a lot smoother, the power is felt, and the overall pleasure of driving is better. It is the same with our bodies – only difference being we need to maintain it every night.

Why do we feel sleepy in the nights?

Ever wonder why we feel sleepy mainly in the nights? Our sleep is governed by circadian rhythms which is more active during the day. Circadian rhythm means the sleep-wake cycle governed by the body’s internal clock.

If we take a step back and look at the history of the human evolution, we get some answers to this question. Unlike other animals, a human is weak in many respects. We do not have the strength, stamina, sensory powers, like other animals. Humans can never run as fast as an antelope or a cheetah, can never match the strength of the lion or elephant, cannot see far like an eagle, cannot hear better than an owl, cannot smell better than a dog or a hyena or a shark…the list is endless. The only difference is that we have a better brain than most animals and we know how to use it to overcome these disadvantages. The human brain has developed much more than our cousins during the process of evolution.

If we study the human development and evolution, the prehistoric humans had to rely on the daylight to see better and use their skills to hunt and survive. When night fell, they were helpless and had to take shelter in a cave till the daylight came. The body obviously adjusted to this pattern and we still feel sleepy when the night sets in. Our bodies produce a chemical called melatonin, which is the main cause for us to feel sleepy after the sun sets.

What happens when we sleep?

According to scientists our sleep is divided into a number of phases which are classified into non REM and REM. REM stands for Rapid Eye Movement. The non REM phase consists of three stages – the first stage where we feel sleepy and feel eyes closing off (the experience similar to what we feel when we listen to long boring speeches in the office or the class!). The second stage is when the mind becomes dull and drowsy and we fall into a light sleep. At this stage the body temperature drops, and our heart slows down too.

The third stage is when we are in deep sleep, where the body is completely at rest and except for the major and important functions rest of the activities are shut down.

The REM part of the sleep is when our temperature is back to normal and heart beats normally and our eyes move rapidly under our eyelids. This is the time when most us have dreams.

The body goes through all the non-REM and REM sleep several times during the hours when we are asleep.

Sleeping improves immunity

Our bodies undergo a few changes when we are asleep. Most important is the release of a protein called cytokines which are necessary for improving our immunity and fighting infections. Without sufficient sleep the cytokines are not released, and our bodies are not able to fight the infections. Hence sleep is very important to improve immunity. It has been observed that people who take the flu vaccine and do not sleep sufficiently, are still susceptible to the flu. This is essentially because cytokines assist the body to fight infection and only vaccination or medication is not sufficient.

This was the same cytokine which multiplied prolifically leading to a cytokine storm in covid 19 situations.

Are we sleeping less?

Though there is a general feeling that we are sleeping less compared to our ancestors. But in a study conducted by the NCBI (National Centre for Biotechnology Information, USA) this myth that we are sleeping less than our ancestors has been dispelled. The amount of sleep required has not changed much from the time we moved out of Africa. The view that the invention of electricity and electric bulb has reduced our sleeping time was found not to be true.

But it is a proven fact that the sleeping patterns have changed considerably.

The global sleep statistics: In a survey conducted by the electronics giant Philips from November 12-December 5 in 2019 among 13000 adults from 13 countries found some interesting observations about the sleep pattern.

“Only 49% of people are satisfied with their sleep, with worry/stress reported as the most limiting factor to a good night’s sleep (33%). Interestingly, fewer people in 2020 are taking action to improve sleep compared to 2019, with nearly all listed strategies to improve sleep lower or consistent in 2020 when compared to 2019 results. For example, reading before bed was the most popular strategy used to improve sleep in 2019 (39%), but only 28% of people report reading to improve sleep in 2020. Other notable distinctions in sleep-related behavior appeared across age and gender differences” - www.philips.com


How long should we sleep?

There are lots of theories and debates as to how long should one sleep? We don’t have a standard measure for this question. Individual requirements vary depending on the age, health, sex and the place.

We all know that babies tend to sleep for hours and hours and only get up to feed and then go back to sleep. As the baby grows slowly the sleep patterns are also change, making it sleep less. Because the baby is in the growth mode, it clearly establishes the fact that sleep is required for our bodies to grow and repair. As the babies grow older, the sleeping pattern slowly adjusts itself to fall in with the circadian rhythms.

As adults it is generally recommended that we should be sleeping at least 6-9 hours depending on each individual's body requirements. All of us are unique individuals and one cannot say that six hours or nine hours are required for one person. Over the time a pattern sets in and each of us know how many hours of sleep we need.

National Sleep Foundation (https://www.sleepfoundation.org) , based in the US have a table which illustrates the amount of sleep a healthy person should be having depending on the age.

Why is that we don’t fall asleep?

Many of us struggle to sleep on time and wake up to a restful and fresh mornings. Why is that we don’t fall asleep quickly? There are multiple reasons why we don’t fall asleep quickly. Research suggests different reasons for many of us not falling asleep. It includes medication, stress, anxiety, diet, excitement, bipolar disorders, trauma, and boredom. It is important to treat the underlying cause to ensure that we fall asleep naturally. If there are no medical or emotional reasons which are preventing us from sleeping quickly, we can try the following to sleep better at night naturally. How to sleep better at night naturally: Here are some simple sleeping tips, practical and easy to implement steps to achieve that good night’s sleep.

1. Timing: The clock in our body is as accurate as your mobile phone. If you condition your body to sleep at a particular time, it is possible to sleep naturally without any difficulty. If you choose to sleep at, say 10 pm, make sure that you go to bed before and by 10pm the lights are switched off and all electronic gadgets are off. Following this ritual without any break will be helpful in the long run.


2. Environment: The bedroom, where possible should be cool and the ambient temperature should be comfortable. If it's too hot or too cold, the body obviously would struggle to adjust itself to the temperature leading to delay in sleeping. Whether you are using an air conditioner or natural ventilation, having a comfortable temperature is important. It is recommended to keep the air conditioner at 22°C, however it is left to individual preferences.


3. Early dinner: We have all heard about the digestion time and why we should give at least two hours between dinner and sleeping. This is a scientifically proven fact and an important factor for good sleep hygiene. Our body generally goes into a state of inactivity during our sleep. As discussed earlier it is the time for repair and maintenance and the general body functions are given a lower priority. If we have dinner and go to bed immediately the food remains undigested for the most part of the night and would create an uncomfortable feeling leading to disturbed sleep throughout the night.


4. Comfortable clothing: Depending on the weather and individual preference, comfortable clothing would assist in creating the ambient conditions for sleeping. Similarly having clean sheets would also help in sleeping better.

5. Avoid coffee and tea: For many having a coffee or tea even 2-5 hours before the sleeping time creates problems in falling asleep. The caffeine in the body keeps them awake for a long hour into the night. There are some who can fall asleep even after drinking a strong cup of tea/coffee a few minutes before the bedtime! Since you would know your body better tea/coffee should be avoided at least 5 hours before the bedtime, if it is likely to keep you awake.

6. Avoid Alcohol: Like caffeine, alcohol is also a stimulant which can disrupt your sleep schedule. Social drinking in a very limited way (say a glass of wine) may help you in your sleeping, but excessive alcohol can make your sleep cycles go haywire besides of course spoiling your health.

7. Say no to gadgets: the screen of the mobile phone or your tablet can cause serious disruption of your sleep. Most of us are habituated to keep the phone on the side and very often it is the last thing that we see before going to bed and the first thing we see when we wake up.

The amount of sleep required might differ from person to person and depending on the age. What is important is to ensure that each of us get the required amount of sleep so that the bodies can do their maintenance bit while we dream in our favorite pastimes.


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