October 25, 2013

How Much Sleep Do We Really Need?

You’ve heard different things—from eight hours a night, to four hours a night—eek!—to 20-minute catnaps throughout a 24 hour day being sufficient.

So, what’s the science have to say about how much sleep we really need?

A new study published in the Proceedings of the National Academy of Sciences found that if you sleep less than six hours a night it affects the activity of 688 genes.

The study was small but interesting. They took 26 participants and exposed them to sleep restriction for one week. Sleep restriction only allowed them to sleep for 5.7 hours per 24 hour cycle.

Then the group was exposed to sufficient sleep for one week. Sufficient sleep was 8.5 hours per 24 hour cycle. Immediately after each week’s sleep study, the participants were exposed to a period of total sleep deprivation where they were not allowed to sleep. After the sleep deprivation, each subject gave RNA samples which were evaluated.

Insufficient sleep has been linked to a number of health concerns including unhealthy weight gain, cognitive and cardiovascular issues, but exactly how lack of sleep impacts health has been largely unknown.

In this study:

  • Just one week of insufficient sleep altered the activity of over 700 genes in human blood cells.
  • Sleep insufficiency also reduces the amplitude of the circadian rhythms on each gene, affecting its activity in a negative way.
  • After the week of insufficiency followed by deprivation, these effects on gene circadian rhythms were intensified.

This indicates that lack of sleep—anything less than six hours per night—may challenge the normal activity of our genetic ability to live in sync with the natural circadian rhythms.

This of course lines up beautifully with Ayurveda’s most near and dear health mandate, which is to live in harmony with these natural cycles.

In a busy life in a stressful world, it might help to know that when you are burning the candle on both ends, you are potentially messing with the expression of your genetic weak links—which, unfortunately, we all have!


1. PNAS 2013 110 (12) E1132-E1141; published ahead of print February 25, 2013, doi:10.1073/pnas.1217154110

Read the related articles here:

Too Tired to Sleep?

Sleep Interrupted: The Blood Sugar and Sleep Connection.


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Ed: Catherine Monkman

{Photo: Pixoto.}


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