Researchers increasingly think that our Circadian rhythm , or body clock, matters more to our sleep than we realise. In fact, one study suggested our internal rhythm might matter more than sleep duration when it comes to feeling rested. And in an Australian paper, which was published in Sleep Medicine , researchers found that people who struggle with racing thoughts that keep them up at night seem to have differences in their Circadian rhythm. “Unlike good sleepers, whose cognitive state shifted predictably from daytime problem-solving to nighttime disengagement, those with insomnia failed to downshift as strongly,” the study’s lead researcher, Professor Kurt Lushington, said . Why might people with racing thoughts at night have different body clocks? In this research, scientists placed 32 adults (half of whom had insomnia; the other half were healthy sleepers) in an environment with as few external body clock cues as possible. They were placed in a bed in a dimly-lit room for 24 hours, with carefully-measured food and activity. This was done to isolate the participant’s Circadian rhythms. The scientists noticed that, even with no factors like sunlight, most participants’ body clock worked roughly in tandem in the daytime: their mental acitivty was highest in the morning and tapered off in the afternoon. But among the insomniacs, whose racing thoughts kept them up at night, some differences were noted later on. Not only was their “cognitive peak” – the time at which their mind was busiest – 6.5 hours later, on average, than those without insomnia, but, Dr Lushington said, “Their thought patterns stayed more daytime-like in the nighttime hours when the brain should be quietening”. Sleep, he added, is “about the brain disengaging from goal-directed thought and emotional involvement. “Our study shows that in insomnia, this disengagement is blunted and delayed, likely due to circadian rhythm abnormalities. This means that the brain doesn’t receive strong signals to ‘power down’ at night.” Is there anything I can do to stop my brain racing at night? According to study co-author Professor Jill Dorrian, this research could help to guide insomnia treatments which focus on sufferers’ body clocks in the future. “These include timed light exposure and structured daily routines that may restore the natural day-night variation in thought patterns,” she said (sleep experts have previously recommended getting some outdoor morning light if you can, as this helps to regulate our Circadian rhythm). Additionally, Professor Dorrian ended, “Practising mindfulness may also help quieten the mind at night”. Related... Turns Out Couples' Sleeping Positions Could Show How Happy They Are Together If You Sleep In The 'Flamingo Position', We Have News For You Sleep Position Mistakes That Can Make Your Back Pain Worse