The power of sleep

Undisturbed sleep of around 7-8 hours is necessary in our quest to live long healthy


If you read Mathew Walker's book, 'Why We Sleep', you will start believing that virtually every disease in the body owes its origin to lack of sleep or sleep related disorders. This is the bane of popular books written for mass market consumption that go overboard to stress a particular point.

Having said that, sleep is an integral part of our daily lives and both, lack of sleep and over-sleeping have deleterious effects on our body. How we sleep, where we sleep, when we sleep, with whom we sleep, are all important issues that affect our health in the short term and our healthspan and lifespan in the long term.

Over the next few months and years, I will keep revisiting this topic. For the time being, let us address some basic questions and answers. A lot of the information is taken from a review article by Dr. Michael Grandner [1].

1. What is the ideal length of sleep?

For adults, it is between 7-9 hours. However, as we age, we tend to need fewer hours of sleep, which can be as less as six. The challenge is the more you read about sleep, the more you start checking your sleep hours and just the knowledge that the amount you sleep is perhaps not within prescribed standards, even if you sleep well, can lead to sleep problems, where none earlier existed. It is a good idea to keep regular sleep hours and if the quality of your sleep is good, not to worry too much about whether you sleep for 6 1/2 or 7 or 8 hours. Typically however, a sleep duration of less than 6 hours is considered to be harmful.

2. Does the quality of sleep matter?

This probably matters more than the length of sleep. If you sleep for 8 hours but are constantly disturbed, or keep getting up, or don’t get enough deep sleep, you may be worse off than someone who sleeps for 6 hours, but has undisturbed deep sleep. How do you know that you have had good sleep? Typically, the way you feel in the morning and throughout the day will help you understand whether you are sleeping well or not. If you constantly feel drowsy and sleepy during the day, it generally means that you are either sleeping less or the quality of your sleep is poor or both.

3. What happens with poor sleep?

Poor sleep is associated with reduced longevity, increased weight gain, chronic inflammation, increased cardiovascular risk, reduced cognition and disordered mental health, among other problems.

4. How can you sleep well?

There are many ways. The first is to have a regular sleeping schedule. The second is to abstain from coffee and similar stimulants for a few hours prior to sleep time. Caffeine results in poor sleep quality; for example, I don’t take caffeine for at least four hours prior to my sleep time. It is also a good idea to put aside your screens for half to one hour before your bedtime, which also helps to reduce the digital noise in your life. The light from your devices can also affect your ability to sleep. Outside noise, improper lighting, lack of activity during the day, your mental state…all of these can be issues that you would need to address on your own. Getting up at night to get to the toilet, which is the bane of older men with enlarged prostates, is also a problem that may need a visit to your family physician or a urologist.

5. What can you do to offset the ill-effects of poor sleep?

There is still a lot we don’t know about sleep. Physical activity, as I wrote about two weeks ago in detail, offsets the cardiovascular risks of poor sleep and it is likely that other factors may also work in tandem to either enhance or blunt the harm from poor sleep. As more and more research on sleep gets published, we will hopefully have a clearer picture in the future of the interplay between sleep, drugs, food, physical activity, coffee, alcohol, etc.

6. Do daytime naps help?

Daytime, afternoon naps of around 30 minutes or less help us to be more productive and alert for the rest of the day and in the long term, improve cognition and lifespans. Longer naps are associated with poorer outcomes, but again, there are no hard and fast rules. You could nap for 35 minutes or 25 minutes and I don’t think that makes a difference.

In short, sleep is important. A good night’s undisturbed deep sleep of around 7-8 hours is necessary in our quest to live long healthy. A short afternoon nap also helps. If you have a problem with sleep, it may be worth introspecting and figuring out solutions on your own first. If these don’t work, it may be a good idea to consult an appropriate doctor or a sleep specialist to find ways and means of improving the quality and length of your sleep.


1. Grandner MA. Sleep, Health, and Society. Sleep Med Clin. 2017 Mar;12(1):1-22.

Dr. Bhavin Jankharia’s new book 'Atmasvasth' available online, dives deeper into this concept. He can provide references for all statements of fact and can be reached at