SLEEP SECRETS

How doctors uncovered the science of sleep

THIS week: The body clock IN 1729, French scientist Jean-Jacques d’Ortous de Mairan concluded that plants have a biological clock.

HE put pot plants in a dark room for several days and found that even in continuous darkness, their leaves continued to open and close in a daily cycle.

In the Sixties, German sleep researcher Jurgen Aschoff studied people inside a dark bunker. By measuring their temperatures and other physical markers, he showed that humans also have internally driven daily (circadian) waking and sleeping cycles. His volunteers all experienced similar reactions at certain times of the day, despite there being no external cues as to the time of day or night. In 1972, American neurologist Dr Robert Moore established the exact location of our body’s master clock, the suprachiasmatic nucleus (SCN), a small region in the hypothalamus — the part of the brain associated with regulating temperature, appetite and our sleep cycle.