Rocking research

Since as long as we can remember, parents have known instinctively that rocking a baby gets it off to sleep more quickly.

However, little is understood about what happens if the movement continues after an infant has dropped off.

Now, a study suggests that continuing gentle rocking after sleep has begun improves not just the quality of a nap, but also brain power.

To explore the phenomenon, scientists at Geneva University carried out experiments on 18 adults, asking them to spend one night on a rocking bed and the next on the same bed which was static.

Monitoring physical characteristics including heart rate, respiratory rate and brain activity, they established that lying down on the moving bed meant the participants fell asleep more quickly, but also had longer periods of deep sleep and fewer “micro-wakes” during the night.

The researchers believe that rocking reinforces deep sleep by modulating brain-wave activity. It also stimulates the synchronisation of the thalamocortico-cortical networks, which play a role in memory.

Aurore Perrault, who worked on the research, said: “To see if this effect also affected memory, we subjected our participants to memory tests.

“They had to learn pairs of words in the evening and remember them in the morning when they woke up. The results were much better after a night in motion than after a still sleep.” The beds in the experiments rocked slowly, moving just 10cm from side to side over a foursecond period.