Review of ‘Dreamland: Adventures in the Strange Science of Sleep’

November 20, 2012

Dreamland: Adventures in the Strange Science of Sleep is a very readable and entertaining popular science book by David K. Randall. In twelve different chapters, he ventures into a different area of sleep research ranging from sleep-walking crimes, to historical sleep patterns to taking advantage of the circadian rhythm to optimize the performance of athletes. It’s a good introduction to some topics on the science of sleep and reads very quickly and fluently. I’ll discuss some of the topics that I found most interesting below.

How Sleep Influences Learning

In an experiment at Harvard, subjects had to play a skiing videogame that involved them more or less realistically moving their bodies in a skiing motion. When the participants were woken up the following ni

Dreamland Cover

ght after two sleep cycles they reported dreaming of skiing. Interestingly, when woken at a later stage their dreams started to incorporate some of the skiing movements but in a different context. Such as moving rapidly through a forest. Randall interprets that as meaning that they started integrating what they learned with memories and associations they already had.

Another experiment showed that depriving participants of those later REM sleep stages when learning a new skill severely deteriorated their performance. When subjects were awoken after less than six hours of sleep following practicing a cognitive task, their performance at the task was much worse after a week. This was the case even when they slept more the following nights and their total sleep equaled that of the control group.

Bad Sleep Causes Dementia

In shocking study, they took a large group of elderly women and brought them to a sleep lab. One in three turned out to have sleep apnea. Sleep apnea is a condition where a person stops breathing for at least ten seconds at various times during the night, usually because the throat obstructs the respiratory airway. It is often undiagnosed, but snoring can be an indication that a person may have it.

Five years later those same women were reexamined and the researcher found that women with sleep apnea were 85% more likely to show first signs of memory loss. The cause for this is most likely that people with sleep apnea spend very little time in restorative sleep stages such as REM and deep sleep.

For me the study on dementia also illustrate the enormous power of having objective data about oneself. A person with a ZEO would be able to notice a gradual decline in sleep and be able to take action about it. Even more powerful is having such data spanning long periods. For example, I’ll be able to tell ten or twenty years down the line how my own sleep changes over time thanks to the data that I’m gathering today with my ZEO. That is enormously powerful.

One Thing He Missed: Vitamin D

There is one chapter, where I feel Randall didn’t do his research properly. He discusses some studies that showed how Japanese nurses working the graveyard shift had higher rates of depression, cardiovascular disease, diabetes, obesity and cancer. The studies attributed that to an overexposure to artificial light. I went back to look at those papers to see whether they controlled for Vitamin D levels. They did not. It has been well-documented that Vitamin D deficiency increases risks for all of those conditions and it is likely that nurses working the night shift were severely Vitamin D deficient. Without controlling for that, I think those studies are worthless and Randall should have picked up on that.

Conclusion: Well-worth a Read

But nonetheless I felt Dreamland was a very good read. It isn’t in-depth or comprehensive, but Randall doesn’t aim to be. Instead he tells a compelling story and manages to pack a lot of interesting stuff in a short and captivating book. One thing I did wish he had written about is the relationship between meditation and sleep. Zen monks reportedly sleep very little and I find the question of whether meditation can replace sleep enormously fascinating…

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