The commonest question I am asked when I give talks on sleep is: “How much sleep do I need?” My response: “As much as it takes for you to feel maximally alert all-day, from the time you wake up to the time you go back to bed.”
Though most adults need 7 – 8 hours of sleep to feel alert and energetic through the day, the need for sleep is as unique as our fingerprints. For you, it can be eight hours, for your spouse, seven hours, while your best friend could do with just six-and-a-half hours. If you’re looking for a magic number then there isn’t one, but there is some recent evidence that sleeping less than seven hours per night can be harmful in the long run.
Why should you aim for at least seven hours
Until recently we did not have a clear-cut, evidence-based recommendation regarding the duration of sleep needed for a healthy life. But, in June 2015, after reviewing 5314 scientific articles, a panel of 15 experts from the American Academy of Sleep Medicine and the Sleep Research Society concluded that adults need seven or more hours of sleep every night.
Here are their specific recommendations:
- Sleeping less than seven hours each night is linked to adverse health conditions such as weight gain, diabetes, high blood pressure, heart disease, stroke and depression. It is also associated with lowered immunity, increased sensitivity to pain, impaired performance, increased chances of errors, and greater risk of accidents.
- Sleeping more than nine hours per night on a regular basis may be appropriate for young adults, individuals recovering from sleep debt, and those with illnesses. For others, it is uncertain whether sleeping more than nine hours per night is associated with any health risk.
- People who are concerned that they are sleeping too little or too much should consult their healthcare provider.
Life is so precious. Why waste one third of it sleeping?
One question that many people often ask is, “I’ve achieved so much in my life by sleeping less, can I not just continue that way?” The answer is: “No, you cannot. Not for long.”
Dr Van Dongen and colleagues at the University of Pennsylvania studied participants after four, six, and eight hours of sleep for 14 days and found a significant dose-dependent decline in their neurological and cognitive performance. Thus, by sleeping less, you may read more, but you will remember less. You may check more e-mails, but your responses will not reflect your true leadership skills. You may interact with more people, but you will be less perceptive. You may work on more problems, but your solutions will be less creative. In short, if you are sleeping less, you might be a liability, as opposed to an asset.
So, by compromising on your sleep you not only increase your risk of diseases mentioned above, but also impair your executive function—creativity, problem-solving, communication, and goal-directed behaviour. These are the reasons why business giants like Warren Buffet, Bill Gates and Satya Nadela try to get 7 – 8 hours sleep despite their busy schedules.
Bill Gates says he gets at least seven hours of sleep a night because “that’s what I need to stay sharp and creative and upbeat.” Jeff Bezos, CEO of Amazon, says, “I’m more alert, and I think more clearly if I’ve had eight hours’ sleep. I just feel so much better all day long if I’ve slept that much.” Marc Anderson, co-founder of Netscape, admits to needing eight hours. He says, “I can get by on seven-and-a-half hours without much trouble. Seven, and I start to degrade. Six is suboptimal. Five is a big problem. Four means I am a zombie.”
What about people who claim to do well with little sleep
What about Indira Gandhi, Margaret Thatcher, Indra Nooyi and the likes, who claimed to sleep only 4 – 5 hours a night? Do they carry a short-sleeper gene? Well, Dr Ying-Hui Fu and her team at the University of California, San Francisco, did find that short-sleeper gene, a rare mutation, is present in three per cent of the population. But it has not been confirmed if there are other health risks of carrying this short-sleeper gene and sleeping so little.
Motivation cannot happen in the absence of creativity, flexibility and the right mood. All of which get hampered due to lack of sleep
My overworked colleagues continue to argue against sufficient sleep. Here is a list of arguments made by these sceptics and my responses:
1 “I don’t need eight hours of sleep.”
Studies have shown that restricting sleep to four or six hours [compared to eight hours] for 14 days causes a decline in your executive function.
2 “I can fight sleep deprivation with strong motivation.”
Motivation cannot happen in the absence of creativity, flexibility and the right mood. All of which get hampered due to lack of sleep.
3 “I have achieved a lot by sleeping less.”
You could achieve even more by sleeping more.
4 “I don’t perceive the deficit in my performance.”
Sleep deprivation adversely affects the prefrontal cortex [area of the brain called “the executive centre”], which is essential for successful self-evaluation. This makes us unaware of our deficit.
5 “I am highly productive even with less sleep.”
You have increased your output as a worker at the expense of leadership output. You are compromising the quality at the expense of quantity.
Sleeping eight hours but it still seems less
I have made my case for 7 – 8 hours of rest every night, but what if you are feeling sleepy and tired despite sleeping eight hours every night?
First, make sure you are getting quality sleep by following good sleep habits—keeping a regular sleep schedule even on weekends, exercising 30 minutes a day, not working in the bed, avoiding caffeine after 1pm, not eating a large meal before bedtime, not consuming alcohol within three hours of bedtime and most importantly, praying or meditating for a few minutes before retiring to bed. Then, make sure you do not suffer from depression or Obstructive Sleep Apnoea, a disease characterised by loud snoring and cessation of breathing for 10 or more seconds all night long.
In conclusion, invest richly in sleep and get the most out of your limited stay on this beautiful earth. Make a commitment, as a family, to get 7 – 8 hours of rest every night. Enjoy lasting alertness, energy, vigour, and vitality; and live a healthy, happy, and a long life.
I leave you with a favourite shloka of mine from the Bhagvad Gita [Chapter 6, Verse 17]
yuktahara-viharasya yukta-cestasya karmasu,
yukta-svapnavabodhasya, yogo bhavati duhkha-ha
(Translation: A person who is temperate in eating, resting, working and recreation can mitigate all material pains by practising yoga.)