A simple breathing trick, dubbed the '4-7-8' technique, can help insomniacs nod off in just 60 seconds. Pioneered by US sleep expert Dr Andrew Weil, it is claimed to help oxygen better fill the lungs, calms the mind and relaxes muscles.

The exercise can be done in any position. First, exhale completely through the mouth while making a 'whoosh' sound. Then, close the mouth and inhale quietly through the nose while counting to four. Next hold a breath for a count of seven. Finally, exhale completely through the mouth, making another 'whoosh' sound for eight seconds. Inhale again and repeat the cycle three times for a total of four breaths.

The technique is based on an ancient Indian practice called pranayama, which means regulation of breath, and is widely used in yoga and pilates.

The Harvard-trained doctor says '4-7-8' helps practitioners feel connected to their body and distracts them from everyday thoughts that can disrupt sleep. He suggests practicing the technique twice a day, for six to eight weeks until being in enough control to drop off to sleep in less than a minute.