The BBC published an article last year about Einstein and his quirky daily routines. The content relating to his sleep regime caught my eye. You can read the full article here.

It covers interesting topics such as spindle events and fluid intellect, and links to a study relating to sleep and enhancing brain activity - here are the highlights:


It’s common knowledge that sleep is good for your brain – and Einstein took this advice more seriously than most. He reportedly slept for at least 10 hours per day – nearly one and a half times as much as the average American today (6.8 hours). But can you really slumber your way to a sharper mind? 

The author John Steinbeck once said: “It is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it.”

Many of the most radical breakthroughs in human history, including the periodic table, the structure of DNA and Einstein’s theory of special relativity, have supposedly occurred while their discoverer was unconscious. The latter came to Einstein while he was dreaming about cows being electrocuted. But is this really true?

Back in 2004, scientists at the University of Lubeck, Germany, tested the idea with a simple experiment. First they trained volunteers to play a number game. Most gradually got the hang of it with practice, but by far the quickest way to improve was to uncover a hidden rule. When the students were tested again eight hours later, those who had been allowed to sleep were more than twice as likely to gain insight into the rules than those who had remained awake.

When we fall asleep, the brain enters a series of cycles. Every 90-120 minutes the brain fluctuates between light sleep, deep sleep and a phase associated with dreaming, known as Rapid Eye Movement (REM), which until recently was thought to play the leading role in learning and memory. But this isn’t the full story. “Non-REM sleep has been a bit of a mystery, but we spend about 60% of our night in this type of sleep,” says Stuart Fogel, a neuroscientist at the University of Ottawa.

Non-REM sleep is characterised by bursts of fast brain activity, so called ‘spindle events’ because of the spindle-shaped zigzag the waves trace on an EEG. A normal night’s sleep will involve thousands of these, each lasting no longer than a few seconds. “This is really the gateway to other stages of sleep – the more you sleep, the more of these events you’ll have,” he says.

Spindle events begin with a surge of electrical energy generated by the rapid firing of structures deep in the brain. The main culprit is the thalamus, an oval shaped region which acts as the brain’s main ‘switching centre’, sending incoming sensory signals in the right direction. While we’re sleeping, it acts like an internal earplug, scrambling external information to help you stay asleep. During a spindle event, the surge travels up to the brain’s surface and then back down again to complete a loop.

Intriguingly, those who have more spindle events tend to have greater ‘fluid intelligence’ – the ability to solve new problems, use logic in new situations, and identify patterns – the kind Einstein had in spades. "They don’t seem related to other types of intelligence, such as the ability to memorise facts and figures, so it’s really specific to these reasoning skills," says Fogel. This ties in nicely with Einstein’s disdain for formal education and advice to "never memorise anything which you can look up".

And though the more you sleep, the more spindle events you’ll have, this doesn’t necessarily prove that more sleep is beneficial. It’s a chicken and egg scenario: do some people have more spindle events because they are smart, or are they smart because they have more spindle events? The jury is still out, but a recent study showed that night-time sleep in women – and napping in men – can improve reasoning and problem solving skills. Crucially, the boost to intelligence was linked to the presence of spindle events, which only occurred during night-time sleep in women and daytime slumbers in men.

It’s not yet known why spindle events would be helpful, but Fogel thinks it may have something to do with the regions which are activated. “We’ve found that the same regions that generate spindles – the thalamus and the cortex [the brain’s surface] – well, these are the areas which support the ability to solve problems and apply logic in new situations,” he says.

Luckily for Einstein, he also took regular naps. According to apocryphal legend, to make sure he didn’t overdo it he’d recline in his armchair with a spoon in his hand and a metal plate directly beneath. He’d allow himself to drift off for a second, then – bam! – the spoon would fall from his hand and the sound of it hitting the plate would wake him up.

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