Internal Time

Till Roenneberg explains the ins and outs of the body clock.

ARE YOU A LARK or an owl? Do you bound out of bed 15 minutes before your alarm sounds, or are you continually hitting the snooze button ‘just one last time’? The culprit is your internal clock, a biological device found even in creatures as lowly as bread mould, which is used to synchronise our waking activities to the Sun.

Roenneberg argues that your ‘chronotype’ – whether you’re an early bird or a night owl – can affect several things in your daily life. He covers topics like why teenagers sleep all day, why people living in the country go to sleep earlier than their counterparts in cities, and why couples tend to have different bedtimes.

Each chapter begins with a fictional account that is intended to draw out the main premise of the chapter. At the end of each story, the science is explained in detail.

Internal Time covers a wide range: from experiments on humans kept in underground bunkers that have been sealed from the outside world, to molecular biology identifying the genes that control our internal clock. The breadth of content is a weakness at times, as the complexity of the concepts presented varies significantly between chapters – some chapters are an intense read.

Overall, this is a fascinating account of the biology that controls our waking lives, whether we realise it or not.

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